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Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)

  • Last Modified: 04/03/2014

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Introduction

Men in the United States get prostate cancer more than any other type of cancer except skin cancer. It is found mainly in older men. In the United States, about one out of five men will be diagnosed with prostate cancer. Most men diagnosed with prostate cancer do not die of it.

Complementary and alternative medicine (CAM) is a form of treatment used in addition to (complementary) or instead of (alternative) standard treatments. CAM treatments generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM.

CAM use among prostate cancer patients is reported to be common. CAM treatments used by prostate cancer patients include certain foods, dietary supplements, herbs, vitamins, and minerals.

This PDQ CAM summary gives general information about using foods and dietary supplements to lower the risk of developing prostate cancer or for treating prostate cancer, its symptoms, or side effects of disease treatment. In addition, this summary has sections for several specific foods or dietary supplements:

More topics will be added over time. These sections include the following information for each food or dietary supplement:

Overview of CAM Use in Prostate Cancer

Studies of CAM use to treat prostate cancer have shown the following:

  • Men who have prostate cancer are more likely to take dietary supplements than men who do not have prostate cancer.

  • Prostate cancer patients with the healthiest eating habits (for example, eating lots of fish rich in omega-3 fatty acids and vegetables) are the most likely to take dietary supplements.

  • Reasons given by prostate cancer patients for using CAM treatments include boosting the immune system, improving quality of life, and lowering the risk of the cancer coming back.

Studies of CAM use to lower the risk of developing prostate cancer or to prevent it from coming back have shown the following:

  • A study of men with a family history of prostate cancer found that over half used vitamins or other dietary supplements, including those sold for prostate health or cancer prevention, such as some of those listed in this summary.

  • A study of men at a prostate cancer screening clinic found that well over half took multivitamins and a smaller number took herbal supplements.

  • A study of prostate cancer survivors found that up to one-third took vitamins or minerals.

  • Although many prostate cancer patients use CAM therapies, only about half of them tell their doctors about their use of CAM.

Studies of why prostate cancer patients do or don't decide to use CAM show that their choice is based on many factors, including their medical history, their beliefs about the safety and side effects of CAM compared to standard treatments, and their need to feel in control of their treatment.

Questions and Answers About Green Tea

  1. What is green tea?

    Tea has been consumed in Asia since ancient times. Sailors first brought tea to England in the 17th century. Other than water, tea is the most widely consumed beverage in the world. Tea comes from the Camellia sinensis plant. The way the leaves of this plant are processed determines the type of tea produced.

    Many of the possible health benefits studied in green tea are thought to be from compounds called polyphenols. Polyphenols are a large group of plant chemicals that include catechins (antioxidants that help protect cells from damage caused by free radicals).

    Catechins make up most of the polyphenols in green tea. The most active catechin in green tea is epigallocatechin-3-gallate (EGCG).

    To make green tea, the tea leaves are roasted in a wok (or, historically, steamed) to preserve the catechins and retain freshness. Black tea is made using a process that causes the catechins and other compounds in the leaves to oxidize, producing darker colored tea. Oolong tea is made from partially oxidized leaves.

    Some studies suggest that green tea may protect against cardiovascular disease and some types of cancer, including prostate cancer. Clinical trials designed to study whether green tea is useful in treating prostate cancer are in the early stages. There is not enough evidence to show whether green tea is effective in treating prostate cancer.

  2. How is green tea administered or consumed?

    Green tea may be consumed as a beverage or taken in dietary supplements.

  3. Have any preclinical (laboratory or animal) studies been conducted using green tea?

    Laboratory and animal research has been done to study the effects of green tea in prostate cancer.

    Studies of green tea in the laboratory have shown the following:

    • EGCG was shown to block the stimulating effect of androgen (a male sex hormone) on human prostate tumor cells, slow their spread, and increase cell death.

    • Human prostate cancer cells were treated with EGCG for 30 minutes and then with radiation. Cells treated with EGCG were less likely to die when exposed to radiation than cells not treated with EGCG before radiation.

    • Prostate cancer cells were treated with either EGCG or EGCG-loaded nanoparticles. While both treatments decreased cell spread and increased cell death, the nanoparticle treatment was more effective at lower levels, suggesting this type of delivery system for EGCG may make it easier for the body to use and improve EGCG's anticancer activity.

    • Green tea polyphenols may cause anticancer effects by blocking histone deacetylases (HDAC) which are found in large amounts in cancer cells, including those in prostate cancer. Treating prostate cancer cells with green tea polyphenols lowered HDAC activity and caused cell death.

    Studies of green tea in animal models of prostate cancer have shown the following:

    • Strains of mice created to develop prostate cancer that acts like human cancer were given either plain water or water treated with green tea catechins (comparable to a human drinking 6 cups of green tea/ day). After 24 weeks, the mice given plain water had developed prostate cancer while the mice given water with green tea catechins showed only prostatic intraepithelial neoplasia (PIN) lesions. The findings suggested that green tea catechins may help delay the development of prostate cancer by blocking a protein involved in cancer growth.

    • In a study of EGCG, mice were implanted with prostate cancer cells and injected with EGCG or placebo 3 times/ week. The mice that received the EGCG treatment had lower levels of proteins needed for androgen activity than those treated with placebo. The findings suggested that EGCG blocks the stimulating effect of androgen on tumor cells in a way that may be useful in prostate cancer that can be treated with hormone therapy and also in prostate cancer that does not respond to hormone therapy.

    • In another study of EGCG, strains of mice created to develop prostate cancer that acts like human cancer were given EGCG in drinking water (comparable to a human drinking 6 cups of green tea/ day) starting at either 12 weeks of age or 28 weeks of age. EGCG treatment prevented high-grade PIN lesions in mice that began treatment at 12 weeks but not in those that began treatment at 28 weeks of age.

    • In a study of green tea polyphenols, these strains of mice were given polyphenols in drinking water starting at different ages (to match different stages of prostate cancer). All the green tea-fed mice were tumor-free longer than water-fed control mice, and the mice that were fed with green tea the earliest benefitted the most.

    • In another study of green tea polyphenols, these strains of mice were fed polyphenols by mouth (comparable to a human drinking 6 cups of green tea/ day). As measured by MRIs over time, tumor development was delayed and tumor growth was slowed in the polyphenol-fed mice compared to water-fed mice. In addition, the polyphenols caused high levels of cell death, possibly limiting the spread of cancer to distant parts of the body.

    • Safety studies of Polyphenon E (a green tea extract with a mixture of catechins) have been done in dogs given various doses by mouth. Mixed findings of safety and harms in fasting dogs compared to fed dogs using different types of Polyphenon E are being reviewed.

  4. Have any clinical trials (research studies with people) of green tea been conducted?

    Population studies and clinical trials have been done to find out if green tea may be useful in preventing or treating prostate cancer.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people.

    A review of many population studies combined, mainly from Asia, showed mixed findings about whether green tea had a protective effect or no effect on prostate cancer risk. Many factors may be involved in these mixed results, including study location, tobacco and alcohol use, and other dietary differences. Black tea was not found to affect prostate cancer risk.

    Overall, population studies suggest that green tea may help protect against prostate cancer in Asian populations. As more people drink green tea worldwide, including in the United States, further population studies will add to information about whether green tea or green tea catechins may help protect against prostate cancer.

    Clinical trials of preventing prostate cancer

    A study assigned 60 men with high-grade prostatic intraepithelial neoplasia (HGPIN) to take green tea catechin capsules (600 mg / day) or a placebo. After 1 year, 9 men in the placebo group were diagnosed with prostate cancer compared to 1 man in the green tea catechin group. The findings suggest that green tea catechins may lower the risk of prostate cancer in patients at high risk for the disease. Two year follow-up showed that this effect was long-lasting. A larger, multicenter trial is underway.

    Clinical trials of treating prostate cancer

    Clinical trials designed to study whether green tea is useful in treating prostate cancer have shown the following:

    Patients scheduled to undergo radical prostatectomy were assigned to drink green tea, black tea, or soda five times/ day for 5 days. Bioavailable tea polyphenols were found in prostate tissue samples of patients who drank either green tea or black tea. In addition, prostate cancer cells treated with blood taken from patients after they drank tea grew and divided more slowly than cells treated with blood taken from patients before they drank tea.

    Fifty patients scheduled to undergo radical prostatectomy were assigned to take Polyphenon E (800 mg EGCG) or a placebo daily for 3 to 6 weeks. Patients treated with Polyphenon E had lower blood levels of prostate specific antigen (PSA) and insulin-like growth factor -1 (a protein linked with increased risk of prostate cancer) than patients treated with placebo, but these differences were not meaningful. The findings suggest that the possible anticancer effects of green tea polyphenols may need to be studied in longer treatment trials.

    A small group of hormone-refractory prostate cancer patients were given capsules of green tea extract (375 mg of polyphenols/ day) for up to 5 months. The study showed that the green tea treatment was well tolerated by most of the patients. However, no patient had a meaningful decrease in PSA levels and all 19 patients had disease progression within 1 to 5 months.

    Patients with androgen-independent prostate cancer that had spread to other places in the body consumed green tea (6 grams / day for up to 4 months). Of the forty-two participants, one had a meaningful decrease in blood PSA levels which did not last longer than 2 months. Green tea was well tolerated by most of the study patients. However, there were 6 reports of serious side effects, including insomnia, confusion, and fatigue. The findings suggest that green tea may have limited benefits in patients with advanced prostate cancer.

  5. Have any side effects or risks been reported from green tea?

    Four Phase I studies of Polyphenon E in single doses or multidoses were done in healthy volunteers. Polyphenon E was given in a range of doses and found to be well tolerated. Side effects were generally mild, with no serious side effects reported. The most frequently reported side effects thought to be related to the drug include headache, nausea, abdominal pain, diarrhea, upset stomach, dizziness, and weakness. Gastrointestinal side effects were usually mild, occurring most often in patients taking the drug on an empty stomach and at the highest doses.

    The FDA Division of Drug Oncology Products recommends that Polyphenon E should be taken with food by patients in clinical trials and that liver function tests should be done during treatment.

    Various types and doses of green tea extracts taken by mouth have been linked with several cases of liver damage in recent years. Most of those affected were women and many were taking green tea extract for weight loss. Most patients recovered within 4 months after stopping the green tea extract. However, there is one case report of acute liver failure in a woman who then needed a liver transplant. Her doctors concluded that her condition was likely caused by over-the-counter green tea extract capsules for weight loss.

    Green tea has been well tolerated in clinical studies of patients with prostate cancer. One study found that the most commonly reported side effects of green tea were gastrointestinal symptoms. These were mild except for two reports of severe anorexia and moderate breathing problems. There is evidence that consuming 10 or more cups of green tea/ day for long periods of time may cause headaches, which may be due to caffeine content in the tea.

  6. Is green tea approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    The U.S. Food and Drug Administration has not approved the use of green tea as a treatment for cancer or any other medical condition.

    Green tea is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI’s list of cancer clinical trials for CAM clinical trials on green tea for prostate cancer and green tea extract for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Lycopene

  1. What is lycopene?

    Lycopene is a carotenoid (a natural pigment made by plants). Lycopene protects plants from stress and helps them use the energy of the sun to make nutrients. Lycopene is found in fruits and vegetables like tomatoes, apricots, guavas, and watermelons.

    The main source of lycopene in the American diet is tomato-based products. Lycopene is more bioavailable (easier for the body to use) in processed tomato products like tomato paste and tomato puree than in raw tomatoes.

    Eating carotenoids, including lycopene, along with dietary fat may help the body absorb them. For example, one study showed that more lycopene was absorbed from diced tomatoes cooked with olive oil than diced tomatoes cooked without olive oil.

    Lycopene in the diet may affect antioxidant activity and communication between cells. Laboratory and animal studies have shown that lycopene may help lower the risk of prostate, skin, breast, lung, and liver cancers. However, clinical trials of whether lycopene lowers cancer risk have shown mixed results.

  2. How is lycopene administered or consumed?

    Lycopene may be consumed in the diet or taken in dietary supplements.

  3. Have any preclinical (laboratory or animal) studies been conducted using lycopene?

    Laboratory research and animal studies have been done to find out if lycopene may be useful in preventing or treating prostate cancer.

    Studies of lycopene in the laboratory have shown the following:

    • Prostate cancer cells treated with lycopene had changes in their cell division cycle, leading to less cancer cell growth.

    • In prostate cancer cells treated with lycopene, cholesterol levels were lower, leading to less cancer cell growth & more cancer cell damage.

    • Treating prostate cancer cells with lycopene may change the way androgen (male hormone) is taken up and used in the cells, causing less cancer cell growth.

    • Combining lycopene with standard cancer drugs may help stop the growth of different types of prostate cancer cells more than when drugs are used alone. Used together with a cancer drug, lycopene may block the way insulin-like growth factor (IGF) is taken up by the cells, causing less cancer cell growth.

    Studies of animal models of prostate cancer treated with lycopene have shown the following:

    • Strains of mice created to develop prostate cancer that acts like human cancer were fed a diet with either lycopene beadlets or tomato paste. Mice on the lycopene beadlet diet had a greater decrease in prostate cancer rates than mice on the tomato paste diet. This suggests that lycopene might have more cancer protective effects than tomato paste.

    • Combining lycopene with a substance found in dried tomatoes (FruHis) slowed the growth of prostate cancer cells in rats more than either lycopene or FruHis alone.

    • A study of mice injected with human prostate cancer cells showed that mice treated with either lycopene or beta carotene supplements had less tumor growth.

    • A study of mice injected with human prostate cancer cells and treated with a certain chemotherapy drug, lycopene, or both showed that those treated with chemotherapy and lycopene lived longer and had smaller tumors than those treated with chemotherapy alone.

  4. Have any population studies or clinical trials (research studies with people) of lycopene been conducted?

    Several population studies and clinical trials have been done to find out if lycopene may be useful in preventing or treating prostate cancer.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people. Population studies of prostate cancer risk have shown the following mixed results:

    • Studies of large groups of men have found that high amounts of lycopene in the diet are linked with a lower risk of developing prostate cancer.

    • Some studies have shown that lycopene levels in the blood and tissue of patients with cancer are lower than in those who do not have cancer. However, other studies have not shown this.

    • Several studies found that men who ate more raw or cooked tomatoes had a slightly lower risk of prostate cancer.

    • A study found no link between lycopene and tomatoes in the diet and prostate cancer risk in the overall population. However, in men with a family history of the disease, higher amounts of lycopene in the diet were linked with a lower risk of prostate cancer. Another study in the same group of men found no difference in blood levels of lycopene between healthy men and men who developed prostate cancer.

    Many issues may be involved in these mixed findings, including sources and types of lycopene, other dietary differences, obesity, tobacco and alcohol use, and genetic risk factors.

    Clinical trials of preventing prostate cancer

    Clinical trials designed to study whether lycopene is useful in preventing prostate cancer have shown the following:

    • Men with benign prostate hyperplasia (BPH) or prostate cancer were given tomato sauce dishes for 3 weeks before scheduled surgery to remove the prostate. The study found that they had markedly lower prostate specific antigen (PSA) levels and more cancer cell death found in the prostate when examined after surgery than a similar group of patients who did not receive the tomato sauce dishes.

    • Men with high-grade prostatic intraepithelial neoplasia (HGPIN) who took lycopene supplements for 2 years had a greater decrease in PSA levels and fewer cases of prostate cancer than those who did not. This indicated that lycopene may be useful in preventing HGPIN from developing into prostate cancer. In another study of men at high risk of prostate cancer (such as men with HGPIN), those who took a daily multivitamin with no lycopene and those who took the same multivitamin plus lycopene (30 mg/ day) for 4 months showed no difference in PSA levels.

    Clinical trials of treating prostate cancer

    Clinical trials designed to study whether lycopene is useful in treating prostate cancer have shown the following:

    • Men with prostate cancer that had not spread were given lycopene supplements (30mg/ day) for 3 weeks before surgery to remove the prostate. Those who received lycopene supplements had smaller tumors and lower PSA levels than those who did not. This study suggests that lycopene may be helpful in treating prostate cancer. Another study of men with prostate cancer that had not spread showed that men who took lycopene supplements (10mg/ day for 1 year) had lower PSA velocity (a measure of how fast PSA levels in the blood increase over time) after treatment.

    • Men who had biochemical relapse of prostate cancer (a rise in the blood level of PSA after treatment with surgery or radiation) were given different doses of lycopene supplements (ranging from 15 mg/ day to 120 mg/ day) for 1 year. Study results showed that lycopene seemed safe & had no side effects, but did not change PSA levels in biochemically relapsed prostate cancer.

    • Men with hormone-refractory prostate cancer (HRPC) (tumors that do not respond to treatment with hormones) were given lycopene supplements for periods of 3 or 6 months in 2 different studies. These studies showed mixed results in lowering PSA levels in men with HRPC.

    • Men with androgen-independent prostate cancer (tumors that do not need androgen to grow) consumed lycopene in either tomato paste or tomato juice daily for 4 months. Study results showed that lycopene may not be effective in lowering PSA levels in androgen-independent cancer.

  5. Have any side effects or risks been reported from lycopene?

    Lycopene has been consumed by prostate cancer patients with very few side effects in many clinical trials. Doses ranging from 10 to 120 mg/ day have caused only occasional gastrointestinal symptoms (e.g. diarrhea, nausea and vomiting, bloating, gassiness and stomach irritation). In one study, symptoms went away when lycopene was taken with meals.

  6. Is lycopene approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

    The U.S. Food and Drug Administration has not approved the use of lycopene as a treatment for cancer or any other medical condition.

    Lycopene is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made. An FDA review in 2007 found that there was not enough evidence to allow a claim that lycopene helps lower cancer risk.

Current Clinical Trials

Check NCI’s list of cancer clinical trials for CAM clinical trials on lycopene for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Modified Citrus Pectin

  1. What is modified citrus pectin?

    Pectin is a type of polysaccharide (a carbohydrate with many small sugar molecules that are chemically linked). Pectin is found in the cell walls of most plants and has gel-like qualities that are useful in making many types of food and medicine.

    Citrus pectin is found in the peel and pulp of citrus fruits such as oranges, grapefruit, lemons, and limes. Citrus pectin can be modified with high pH and heat to break its molecules into smaller pieces. Modified citrus pectin (also called MCP) can be digested and absorbed by the body.

  2. How is MCP administered or consumed?

    MCP may be taken by mouth in powder or capsule form.

  3. Have any preclinical (laboratory or animal) studies been conducted using MCP?

    A study in prostate cancer cells compared 3 different kinds of pectin: citrus pectin, PectaSol (a dietary supplement with MCP), and fractionated pectin powder. Prostate cancer cells treated with the pectin powder had more damage than those treated with citrus pectin or PectaSol. However, when citrus pectin was modified by heating it, it caused the same amount of damage to prostate cancer cells as the pectin powder.

    Only a few studies have reported the effects of MCP in animal models of cancer, including one prostate cancer study. Rats injected with prostate cancer cells and treated with MCP showed less spread of the cancer to the lungs but no effect on tumor growth at the original cancer site.

  4. Have any population studies or clinical trials (research studies with people) of MCP been conducted?

    A few studies in prostate cancer patients suggest that MCP may have some anticancer benefits.

    In a study of patients with advanced solid tumors, including prostate cancers, MCP powder in water was given 3 times/ day for at least 8 weeks. The study showed some quality of life improvements in physical functioning, overall health, fatigue, pain, and insomnia. About one-fourth of patients showed stable disease after 8 weeks of treatment and a smaller number had stable disease for more than 24 weeks. Since the study did not include a group of patients who did not receive MCP for comparison, it was not designed to be able to tell if any of these changes were due to the addition of MCP. The primary goal of the study was to determine if MCP would be well tolerated by cancer patients, and it was.

    In a study of the effect of MCP on prostate-specific antigen (PSA) doubling time (how long it takes PSA levels in the blood to increase by 100 percent), prostate cancer patients who had rising PSA levels were given 6 PectaSol capsules 3 times/ day for 12 months. After treatment, 7 out of 10 patients showed a slowing of PSA doubling time.

  5. Have any side effects or risks been reported from MCP?

    Two studies of MCP showed that most patients had very few side effects. Itching, stomach upset, and gassiness were reported in one study. In another study, 3 patients had abdominal cramps and diarrhea that went away when their treatment was stopped.

  6. Is MCP approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

    The U.S. Food and Drug Administration has not approved the use of MCP as a treatment for cancer or any other medical condition.

    MCP is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI’s list of cancer clinical trials for CAM clinical trials on modified citrus pectin for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Pomegranate

  1. What is pomegranate?

    The pomegranate fruit (Punica granatum L.) is native to Asia and grown throughout the Mediterranean, Southeast Asia, East Indies, Africa, and the United States. Pomegranate has been used for medicinal purposes since ancient times.

    Different parts of the pomegranate fruit have bioactive compounds (chemicals found in small amounts that have actions in the body that may promote good health). These include:

    • The peel, which makes up half the fruit and contains bioactive compounds such as phenolics, flavonoids, and ellagitannins (the main source of antioxidant activity);
    • The seeds, which contain punicic acid, an omega-5 fatty acid; and
    • The aril (outer layer surrounding the seeds), which contains phenolics and flavonoids including anthocyanins, which give the pomegranate fruit and juice their red color.
  2. How is pomegranate administered or consumed?

    Pomegranate may be consumed in the diet or taken in dietary supplements.

  3. Have any preclinical (laboratory or animal) studies been conducted using pomegranate?

    Laboratory studies of pomegranate in cancer cell lines include the following:

    • A study of 13 pomegranate compounds showed some were able to slow the growth and spread of prostate cancer cells and to cause cell death. Higher doses were found to be more effective. Punicic acid (a bioactive compound found in pomegranate seeds) was shown to have the strongest effect in causing cell death.

    • Three types of prostate cancer cell lines were treated with either pomegranate extract, pomegranate juice, or two of their bioactive compounds. All pomegranate treatments were shown to increase cell death and decrease the spread of cancer cells, with higher doses found to be more effective. In the cell line that was dependent on androgen (male hormone) for growth, all treatments affected the way androgen was taken up and used.

    • Other studies in cancer cell lines found that the anticancer activity of pomegranate included effects on certain enzymes and pathways involved in cancer, such as the insulin-like growth factor (IGF) system.

    Studies of animal models of prostate cancer in which the animals were given pomegranate have shown the following:

    • A study of mice injected with prostate tumor -forming cells found that mice that drank pomegranate extract in water had tumors that were smaller and took longer to develop than tumors in mice that drank normal water.

    • In a study of strains of mice created to develop prostate cancer that acts like human cancer, all mice that were given normal water for 28 weeks developed tumors. Only one-fifth to one-third of the mice that received pomegranate extract in water developed tumors, with the mice that received the highest amounts of pomegranate extract having the fewest tumors.

  4. Have any clinical trials (research studies with people) of pomegranate been conducted?

    Two clinical trials that studied pomegranate in prostate cancer patients have been fully reported.

    In a study of 48 patients with rising prostate-specific antigen (PSA) levels after surgery or radiation therapy, patients were given 8 ounces of pomegranate juice daily for up to 33 months. Drinking pomegranate juice was related to a slowing of PSA doubling time (how long it takes PSA levels in the blood to increase by 100 percent). In addition, when prostate cancer cells (LNCaP) in the lab were treated with study patients’ blood before and after the study, there was a decrease in cell growth and increase in cell death following pomegranate treatment.

    In a study of patients with rising PSA levels after therapy for localized prostate cancer, patients were given 1 gram or 3 gram doses of pomegranate extract. Both doses of pomegranate extract were related to a slowing of PSA doubling time.

  5. Have any side effects or risks been reported from pomegranate?

    Two studies of pomegranate juice in either prostate cancer patients or patients with erectile dysfunction reported no serious side effects.

  6. Is there any reason people should avoid pomegranate juice?

    Some pomegranate products may contain added sugar. Certain groups, such as the American Institute for Cancer Research (AICR), recommend avoiding sugary drinks. For more information, see the AICR website.

  7. Is pomegranate approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

    The U.S. Food and Drug Administration has not approved the use of pomegranate as a treatment for cancer or any other medical condition.

    Pomegranate is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI’s list of cancer clinical trials for CAM clinical trials on pomegranate-extract pill for prostate cancer, pomegranate juice for prostate cancer, and pomegranate liquid extract for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Selenium

  1. What is selenium?

    Selenium is a trace mineral (a nutrient that is essential to humans in tiny amounts). Selenium is found in certain proteins that are active in many body functions, including reproduction and immunity. Food sources of selenium include meat, vegetables, and nuts. The amount of selenium found in the food depends on the selenium content of the soil where the food grows. Selenium is stored in the thyroid gland, liver, pancreas, pituitary gland, and kidneys.

    Selenium is found in an enzyme called glutathione peroxidase which acts as an antioxidant. However, in high amounts, selenium may act as a pro-oxidant (a substance that can make oxygen byproducts that may damage cells).

    Selenium may play a role in many diseases, including cancer. Animal and population studies have suggested that supplementing the diet with selenium may lower the risk of cancer. Results from the Nutritional Prevention of Cancer Trial (NPC) showed that, although selenium supplements did not affect the risk of skin cancer, they markedly lowered the rates of lung, colorectal, and prostate cancer. However, studies of how selenium levels in the blood affect the risk of developing of prostate cancer have shown mixed results.

    The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was begun by the National Institutes of Health in 2001 to study the effects of selenium and/or vitamin E on the development of prostate cancer.

  2. How is selenium administered or consumed?

    Selenium may be consumed in the diet or taken in dietary supplements. For adults, the recommended daily allowance for selenium is 55 µg/day.

  3. Have any preclinical (laboratory or animal) studies been conducted using selenium?

    Laboratory studies to find out if selenium may be useful in preventing or treating prostate cancer have shown the following:

    • Different forms of selenium have been shown to slow the growth and spread of prostate cancer cells.

    • Selenium nanoparticles may be less toxic to normal tissues than other selenium compounds.

    Studies of selenium in animal models of prostate cancer have shown the following:

    • A study in mice looked at the effect of dietary selenium on prostate cancer prevention starting at different ages. Adult mice and younger mice were fed selenium-enriched diets or diets with no selenium for 6 months or 4 weeks and then injected with human prostate cancer cells. Adult mice with selenium in their diets developed fewer tumors than adult mice with diets lacking in selenium. However, in younger mice, dietary selenium had no effect on tumor development.

    • Strains of mice which developed prostate cancer that acts like human cancer were treated with 2 forms of selenium, MSeA and methylselenocysteine (MSeC), or water only. In the selenium-treated mice, growth of precancerous lesions was slowed and cancer cell death was increased compared to the water-treated mice. MSeA treatment also increased survival time of the study mice. The mice that received MSeA treatment starting at 10 weeks of age had less aggressive prostate cancer than did mice starting treatment at 16 weeks of age, suggesting early treatment with MSeA may be more effective than later treatment.

  4. Have any population studies or clinical trials (research studies with people) of selenium been conducted?

    Population studies and clinical trials have been done to find out if selenium may be useful in preventing or treating prostate cancer.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people.

    Studies of how selenium levels in the blood affect the risk of developing of prostate cancer have shown mixed results. One study tracking subjects for up to 10 years found that men with higher levels of selenium in their blood had a lower risk of prostate cancer. Another study found that prostate cancer patients had lower whole blood selenium levels than did healthy men. However, a 2009 study of prostate cancer patients found that men with higher selenium levels in their blood were at greater risk of being diagnosed with aggressive prostate cancer. These differences may be due to genetic variations among individual patients.

    Clinical trials of preventing/ treating prostate cancer

    Clinical trials of the effects of selenium on prostate specific antigen (PSA) levels or the development of prostate cancer have shown mixed results, including the following:

    • In a study reported in 2013, men at high risk for prostate cancer were given either daily doses of high-selenium yeast (200 µg or 400 µg) or a placebo for up to 5 years. There were no differences in prostate cancer rates or PSA velocity in men who took the selenium supplement compared to those who took the placebo.

    • In an earlier study, men with high-grade prostatic intraepithelial neoplasia (HGPIN) were given either a selenium supplement (200 µg/ day) or a placebo for 3 years or until they were diagnosed with prostate cancer. The results suggested that selenium supplements had no effect on prostate cancer risk.

    • Sixty men were given either a selenium glycinate supplement (200 µg/ day) or a placebo for 6 weeks. Blood samples were collected at the start and the end of the study. Compared to the placebo group, men who received selenium supplements showed higher activity of two selenium enzymes in their blood and lower levels of PSA at the end of the study.

    The Selenium and Vitamin E Cancer Prevention Trial (SELECT)

    The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was a large clinical trial begun by the National Institutes of Health in 2001 to study the effects of selenium and/or vitamin E on the development of prostate cancer. Over 35,000 men, aged 50 years and older, were randomly assigned to receive one of the following combinations daily for 7-12 years:

    • Vitamin E (alpha-tocopherol acetate, 400 IU / day) and a placebo;
    • Selenium (L-selenomethionine, 200 mcg/ day) and a placebo;
    • Vitamin E and selenium; or
    • Two placebos.

    First results reported in 2009 found no meaningful differences in rates of prostate cancer among the 4 groups. In the Vitamin E alone group, there was a slight increase in the rate of prostate cancer and in the selenium alone group, there was a slight increase in the rate of diabetes. Even though these changes were not clearly shown to be due to the supplement, the men in the study were advised to stop taking the study supplements.

    Updated results in 2011 showed that the rate of prostate cancer was markedly higher in the vitamin E alone group compared with the placebo group. There was also a slight increase in the rate of prostate cancer in men who had taken selenium compared with placebo.

    Several factors may have affected study results, including the dose of vitamin E chosen and the form of selenium used. The higher blood levels of selenium in men taking part in this study (compared with men in other studies) may have played a role since it has been suggested that the preventive effects of selenium against prostate cancer are found in men who start with lower levels of selenium.

  5. Have any side effects or risks been reported from selenium?

    Selenium supplements were well tolerated in many clinical trials. In two published trials, there were no differences reported in adverse effects between placebo or treatment groups. However, in the SELECT trial, selenium supplements were linked with a slight increase in the rate of diabetes mellitus.

  6. Is selenium approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    The U.S. Food and Drug Administration has not approved the use of selenium supplements for the treatment or prevention of cancer or any other medical condition.

    Selenium is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI ’s list of cancer clinical trials for CAM clinical trials on selenium for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Soy

  1. What is soy?

    The soybean plant has been grown in Asia for food since ancient times. Soy first arrived in Europe and North America in the 18th century. The soybean can be processed into a wide variety of products including soy milk, miso, tofu, soy flour, and oil.

    Soy foods contain many phytochemicals that may have health benefits. Isoflavones are the most widely researched compounds in soy. Major isoflavones in the soybean include genistein (which may be the most bioactive isoflavone), daidzein, and glycitein. Isoflavones protect the soybean plant from stress and have antioxidant, antimicrobial, and antifungal actions.

    Isoflavones are phytoestrogens (estrogen -like substances found in plants) that attach to estrogen receptors in cells. Genistein has been shown to affect many pathways in prostate cancer cells involved in the growth and spread of cancer.

  2. How is soy administered or consumed?

    Soy may be consumed in the diet or taken in dietary supplements.

  3. Have any preclinical (laboratory or animal) studies been conducted using soy?

    Laboratory research and animal studies have been done to find out if soy may be useful in preventing or treating prostate cancer.

    Studies of soy in the laboratory have shown the following:

    • Several laboratory studies have found that treating human prostate cancer cells with isoflavones (such as genistein or daidzein) interferes with pathways in prostate cancer cells related to inflammation and cancer growth and spread.

    • Some laboratory studies have found that treating prostate cancer cells with whole soy extract (containing all the major isoflavones) or combining other plant-based compounds with isoflavones may have more anticancer effects than using single isoflavones. One study compared treating human prostate cancer cells with soy isoflavones, curcumin (a yellow pigment of the spice turmeric that is being studied in cancer prevention), or a combination of the two compounds. Results showed that combining curcumin and isoflavones was more effective in lowering prostate-specific antigen (PSA) levels than using either compound alone.

    Studies of animal models of prostate cancer treated with soy have shown the following mixed results:

    • Strains of mice created to develop prostate cancer that acts like human cancer were fed a diet with genistein or a control diet. Compared with mice on the control diet, the mice fed the genistein diet had less prostate cancer cell growth and lower levels of growth promoting proteins.

    • A study of mice that were genetically modified to produce prostate cancer found that mice fed a low-dose genistein diet had more spread of cancer than mice fed either a high-dose genistein diet or a diet with no genistein. This suggests that the effects of genistein on prostate cancer may vary depending on dose and on how early it is given.

    • A study in mice implanted with advanced human prostate cancer found that those given daily genistein in peanut oil developed more tumors in other parts of the body than mice given peanut oil without genistein.

    • In a study of combining radiation therapy with soy isoflavones, mice implanted with prostate cancer cells were treated with genistein, mixed isoflavones (genistein, daidzein, and glycitein), and/ or radiation. Mixed isoflavones were found to be more effective than genistein in slowing prostate tumor growth. Combining mixed isoflavones with radiation was found to be most effective in slowing tumor growth.

  4. Have any population studies or clinical trials (research studies with people) of soy been conducted?

    Many population studies and clinical trials have been done to find out if soy may be useful in preventing or treating prostate cancer. Soy products studied include dietary supplements, drinks, and bread.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people. Population studies of soy intake and prostate cancer risk have shown the following:

    • A review of many studies combined showed that men eating large amounts of nonfermented soy foods (for example, tofu and soybean milk) had a lower risk of prostate cancer. Eating large amounts of fermented foods (for example, miso) was not found to affect the risk of prostate cancer.

    Clinical trials of preventing prostate cancer

    • In a study of Japanese men who underwent a prostate biopsy but who did not have cancer, some received a daily supplement of soy isoflavones (40 mg) and curcumin (100 mg), while others received a placebo. After 6 months, there were no differences in PSA levels between the supplement group and the placebo group overall. However, among patients with higher PSA levels at the start, those who received the supplement had meaningful decreases in PSA levels compared to patients in the placebo group.

    • A study was done to find out if a soy diet standard in Asia would be practical for European men to follow. Healthy men ate either a high-soy (2 daily soy servings) or low-soy (usual) diet for 3 months, then crossed over to the other diet. Lower PSA levels were seen with the high-soy diet. Results showed that study volunteers were able to follow the high-soy diet.

    • Men at risk for prostate cancer or with low-grade prostate cancer were given either soy protein, alcohol -washed soy protein (which is lower in isoflavones), or milk protein (which has no isoflavones) for 6 months. PSA levels did not differ among the groups at 3 months or 6 months. Fewer cases of prostate cancer were found after 6 months in men who consumed either type of soy protein than in men who consumed milk protein.

    Clinical trials of treating prostate cancer

    • In a trial of soy isoflavones, prostate cancer patients with rising PSA levels who had been treated with radiation therapy consumed a soy drink daily for 6 months. The soy drink contained 65-90 mg of isoflavones. Results showed that the soy drink had very few side effects and slowed PSA doubling time (how long it takes PSA levels in the blood to increase by 100 percent). These findings indicate that consuming the soy drink may have helped slow the progression of prostate cancer.

    • In a trial of genistein (a major isoflavone), prostate cancer patients scheduled for radical prostatectomy received either a placebo or genistein (30 mg/ day) for 3-6 weeks before surgery. PSA levels in patients who received genistein decreased slightly while PSA levels in those who received the placebo increased slightly.

    • A trial of a soy protein supplement (containing 60 mg/ day of isoflavones) studied patients with early-stage prostate cancer. Those who received the supplement for 12 weeks had slightly greater decreases in PSA and testosterone levels than those who received placebo.

    • Trials of whole soy were done in men scheduled for surgery to remove the prostate. In one study, patients given soy supplements for 2 weeks before surgery showed much higher levels of isoflavones in prostate tissue than in blood. In another study, patients who ate high-phytoestrogen bread (containing soy or soy and linseed) had greater decreases in PSA levels than those who ate wheat bread.

    • A trial of a soy isoflavone supplement was done in prostate cancer patients receiving antiandrogen therapy. Side effects of antiandrogen therapy may include sexual dysfunction, lower quality of life, and changes in mental functioning. Men who received the isoflavone supplement (160 mg/day) for 12 weeks showed no improvement in side effects of antiandrogen therapy compared to men who received a placebo.

  5. Have any side effects or risks been reported from soy?

    Soy products and isoflavones have been consumed by prostate cancer patients with very few side effects in many clinical trials. The most commonly reported side effects were minor gastrointestinal symptoms.

  6. Is soy approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

    The U.S. Food and Drug Administration has not approved the use of soy as a treatment for cancer or any other medical condition.

    Soy is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI’s list of cancer clinical trials for CAM clinical trials on soy isoflavones for prostate cancer and soy protein isolate for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Vitamin D

  1. What is vitamin D?

    Vitamin D (also called calcipotriol, cholecarciferol, or ergocalciferol) is a fat-soluble vitamin found in enriched dairy products, fatty fish, fish liver oil, and eggs.

    Vitamin D has many actions in the body including:

    Vitamin D is needed for bone growth and protects against osteoporosis in adults. Vitamin D level is usually checked by measuring the amount of 25-hydroxyvitamin D in the blood.

  2. What are the sources of vitamin D?

    Vitamin D is made naturally by the body when exposed to sunlight. Vitamin D may also be consumed in the diet or taken in dietary supplements.

  3. Have any preclinical (laboratory or animal) studies been conducted using vitamin D?

    Laboratory and animal research studies suggest that vitamin D may have effects on prostate cancer cells through various pathways.

    Preclinical studies of vitamin D in prostate cancer have shown the following:

    • A study of a form of vitamin D showed that it may prevent prostate cancer cells from sticking to endothelium, the thin layer of cells that lines the inside of blood vessels, lymph vessels, and body cavities.

    • In a 2011 study, mice were fed a diet with adequate vitamin D or a diet lacking vitamin D and were then injected with prostate cancer cells into bone marrow or into soft tissues. The mice lacking vitamin D developed bone tumors that were larger and grew faster than the mice that had adequate levels of vitamin D. However, there was no difference in soft tissue tumors among mice with different vitamin D levels. Results of this study show that a lack of vitamin D is linked with growth of prostate cancer cells in bone but not in soft tissue.

    • A study of vitamin D as adjuvant therapy (therapy to make other types of treatment more effective) combined it with cryotherapy (freezing). Mice injected with prostate cancer cells were treated with calcitriol with or without cryotherapy. Those who were treated with the combination of calcitriol and freezing had more cancer cell death and less cancer cell spread than those who were treated with either calcitriol alone or freezing alone.

  4. Have any population studies or clinical trials (research studies with people) of vitamin D been conducted?

    Many population studies and clinical trials have been done to find out if vitamin D may be useful in preventing or treating prostate cancer.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people. Population studies of vitamin D and prostate cancer risk have shown the following mixed results:

    • Vitamin D levels in patients with prostate cancer that had not spread were taken annually for 5 years. Throughout the course of the study, lack of vitamin D was a common finding among these patients.

    • Another study in patients with prostate cancer suggested that medium or high levels of vitamin D in the blood may be linked with better outcomes than lower levels. These findings indicate that vitamin D levels may play a role in whether or not the disease will worsen and may be a factor in predicting outcome in prostate cancer patients.

    • One thousand patients with prostate cancer and 1000 control patients in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study were followed for up to 20 years. Results suggested that men with higher blood levels of vitamin D had a greater risk of developing prostate cancer than men with lower vitamin D levels.

    • Vitamin D from sunlight exposure has been studied for possible effects on prostate cancer rates. A 2006 study found that PSA levels rise at a slower rate during the spring and summer compared to other times of the year, suggesting this may be due to higher vitamin D levels during those months. Another study found that while men with low levels of sun exposure had increased risk of all prostate cancers, those with prostate cancer who had less sun exposure showed lower risk of advanced disease.

    • Geographic patterns of deaths in the United States from 1950 to 1994 showed that higher death rates from prostate cancer occurred in parts of the country with lower levels of UV radiation from sunlight. This effect is strongest in places more than 40 degrees north of the equator, where sunlight is weakest during the winter months. These findings support the theory that lack of vitamin D increases the risk for prostate cancer.

    Clinical trials of treating prostate cancer

    Clinical trials in patients with prostate cancer have shown the following:

    • A clinical trial treated patients with prostate cancer that had recurred (come back) with calcitriol (the active form of vitamin D) and naproxen for 1 year. Results showed that the combination of calcitriol and naproxen was effective in slowing the rate of rising PSA levels in study patients, suggesting it may slow disease progression.

    • In a 2010 study, patients with prostate cancer that did not respond to hormone therapy were treated with calcitriol and dexamethasone. The results indicated that while the treatment was well tolerated, it did not have an effect on PSA levels in the study patients.

    • In a 2009 study, patients with locally advanced or metastatic prostate cancer were treated with vitamin D. The study reported that one in every 5 patients who took vitamin D had improved PSA levels, suggesting that vitamin D may be an effective therapy for patients with advanced prostate cancer.

    Reviews of many studies combined

    A 2008 review of 45 observational studies combined found no link between intake of vitamin D and prostate cancer risk. A 2011 review of 25 studies combined found no link between either vitamin D in the diet or blood levels of vitamin D and the risk of prostate cancer.

  5. Is vitamin D approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    The U.S. Food and Drug Administration has not approved the use of vitamin D as a treatment for cancer or any other medical condition.

    Vitamin D is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI ’s list of cancer clinical trials for CAM clinical trials on vitamin D for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Vitamin E

  1. What is vitamin E?

    Vitamin E is a nutrient that may protect against chronic diseases such as cardiovascular disease. Vitamin E is being studied in the prevention of some types of cancer.

    There are eight different forms of vitamin E: four tocopherols (α-, β-, γ-, and δ-) and four tocotrienols (α-, β-, γ-, and δ-). Compared with other tocopherols, α-tocopherol (the form of vitamin E commonly found in dietary supplements) is found in greater amounts in the body and is the most active. Most vitamin E in the diet comes from γ-tocopherol. Food sources of vitamin E include vegetable oils, nuts, and egg yolks.

    Many of the possible health benefits of Vitamin E may be from its antioxidant activity. Vitamin E is a powerful antioxidant that protects cell membranes from damage caused by free radicals. Vitamin E also has other functions involved in cell signaling pathways and gene expression.

  2. How is vitamin E administered or consumed?

    Vitamin E may be consumed in the diet or taken in dietary supplements.

  3. Have any clinical trials (research studies with people) of vitamin E been conducted?

    Population studies and clinical trials have been done to find out if vitamin E may be useful in preventing or treating prostate cancer.

    Population studies

    Population studies look for risk factors and ways to control disease in large groups of people. Population studies of vitamin E in prostate cancer risk have shown the following:

    • The NIH -AARP Diet and Healthy Study studied whether vitamin E in supplements and in the diet of volunteers may prevent prostate cancer. After 5 years, no link between vitamin E supplements and prostate cancer risk was found. However, a lower risk of advanced prostate cancer was found in those who had high intakes of one form of vitamin E ( γ-tocopherol).

    • In a 2010 study that measured blood levels of trace elements and vitamin E, those who had prostate cancer had markedly lower blood levels of vitamin E than those who did not have prostate cancer. In addition, those who had higher PSA levels had lower levels of vitamin E in their blood.

    • Blood levels of α-tocopherol and γ-tocopherol and prostate cancer risk were studied in participants in the Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial. Men with higher levels of α-tocopherol had lower rates of prostate cancer, but this was noted only in current smokers and those who had recently quit.

    Clinical trials of preventing or treating prostate cancer

    • In the Physicians’ Health Study II, men received either vitamin E supplements (400 IU synthetic α-tocopherol taken every other day) and/or vitamin C supplements (500 mg synthetic ascorbic acid taken daily) and were followed for an average of 8 years. The overall rates of prostate cancer were very similar in the men who received vitamin E supplements and in those who did not, suggesting that vitamin E may not prevent prostate cancer. Furthermore, vitamin E did not have an effect on total cancer or death rates in these participants.

    • The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study (ATBC) trial measured blood levels of α-tocopherol and dietary intake of vitamin E in men who were followed for up to 19 years. Findings showed no link between vitamin E in the diet and prostate cancer risk, but showed that higher levels of α-tocopherol in the blood may be linked with a lower risk for developing advanced prostate cancer.

    • Men in the ATBC trial who developed prostate cancer were studied to find out if serum α-tocopherol levels affected survival time. Higher serum α-tocopherol levels, at both time of diagnosis and at the 3-year time point, were linked with improved prostate cancer survival.

    • A 2011 study of men who took part in The Carotene and Retinol Efficacy Trial (CARET) found that, among those who were current smokers, higher levels of serum α- and γ-tocopherols were linked with lower risk of aggressive prostate cancer.

    The Selenium and Vitamin E Cancer Prevention Trial (SELECT)

    The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was a large clinical trial begun by the National Institutes of Health in 2001 to study the effects of selenium and/or vitamin E on the development of prostate cancer. Over 35,000 men, aged 50 years and older, were randomly assigned to receive one of the following combinations daily for 7-12 years:

    • Vitamin E (alpha-tocopherol acetate, 400 IU/ day) and a placebo;
    • Selenium (L-selenomethionine, 200 mcg/ day) and a placebo;
    • Vitamin E and selenium; or
    • Two placebos.

    First results reported in 2009 found no meaningful differences in rates of prostate cancer among the 4 groups. In the Vitamin E alone group, there was a slight increase in the rate of prostate cancer and in the selenium alone group, there was a slight increase in the rate of diabetes. Based on those findings, the men in the study were advised to stop taking the study supplements.

    Updated results in 2011 showed that the rate of prostate cancer was markedly higher in the vitamin E alone group compared with the placebo group. There was also a slight increase in the rate of prostate cancer in men who had taken selenium compared with placebo.

    Several factors may have affected study results, including the dose of vitamin E chosen and the form of selenium used. The higher blood levels of selenium in men taking part in this study (compared with men in other studies) may have played a role since it has been suggested that the preventive effects of selenium against prostate cancer are found in men who start with lower levels of selenium.

  4. Have any side effects or risks been reported from vitamin E?

    Alpha-tocopherols are deemed Generally Recognized as Safe by the U.S. Food and Drug Administration.

    In the Physicians’ Health Study II, there were no marked differences in rates of gastrointestinal symptoms, fatigue, drowsiness, skin discoloration or rashes, or migraine between men who took vitamin E (400 IU every other day of alpha-tocopherol) and those who took a placebo. However, there was a higher number of hemorrhagic strokes in men who took vitamin E than in men who took a placebo. In the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group, there was also an increase in hemorrhagic strokes among men in the group that took vitamin E (50 mg/ day of alpha-tocopherol).

    Earlier results from the SELECT trial showed no marked differences in rates of less severe adverse effects (such as hair loss, inflamed skin, and nausea) in the groups that took vitamin E (400 IU/ day of all rac-α-tocopheryl acetate) compared to the other treatment groups. Later follow-up of SELECT participants showed an increased risk of prostate cancer among men in the vitamin E alone group.

  5. Is vitamin E approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    The U.S. Food and Drug Administration has not approved the use of vitamin E as a treatment for cancer or any other medical condition.

    Vitamin E is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Current Clinical Trials

Check NCI ’s list of cancer clinical trials for CAM clinical trials on vitamin E for prostate cancer that are actively enrolling patients.

General information about clinical trials is also available from the NCI Web site.

Questions and Answers About Zyflamend

  1. What is Zyflamend?

    Zyflamend is a dietary supplement that contains 10 different herbs. Zyflamend contains extracts of rosemary, turmeric, ginger, holy basil, green tea, hu zhang (Polygonum cuspidatum, a source of resveratrol), Chinese goldthread, barberry, oregano, and Baikal skullcap.

    The extracts found in Zyflamend have anti-inflammatory activity and possible anticancer benefits. There is limited evidence about how Zyflamend may act against tumor growth. Zyflamend has been shown to interfere with the activity of COX-1 and COX-2 enzymes, which are involved in the development of inflammation and possibly cancer. Zyflamend may also act against the NF-kappa B and lipoxygenase (LOX) families of proteins that stimulate tumor growth.

  2. How is Zyflamend administered or consumed?

    Zyflamend is taken as a dietary supplement in capsule form.

  3. Have any preclinical (laboratory or animal) studies been conducted using Zyflamend?

    Laboratory and animal research has recently been done to study the effects of Zyflamend in cancer.

    Studies of Zyflamend in the laboratory have shown the following:

    • Human prostate cancer cells treated with different doses of Zyflamend had lower androgen (male hormone) receptor and prostate-specific antigen (PSA) levels compared with cells treated with a control substance; higher doses of Zyflamend were found to be more effective. Prostate cancer cells treated with both Zyflamend and bicalutamide (a nonsteroidal antiandrogen drug) showed lower levels of cell growth, PSA, and cancer survival proteins than prostate cancer cells treated with Zyflamend or bicalutamide alone.

    • A study in human prostate cancer cells found that a higher concentration of Zyflamend blocked both COX-1 and COX-2 activity; a lower concentration of Zyflamend blocked COX-2 activity but had less effect on COX-1. Zyflamend was also found to limit the growth of prostate cancer cells. However, the prostate cancer cells in the study did not have high levels of COX-2, suggesting that Zyflamend may have effects on prostate cancer cells that are not related to COX activity.

    • Prostate cancer cells were treated with insulin-like growth factor -1 (IGF-1, a protein linked with increased risk of prostate cancer) alone or together with Zyflamend. Cells treated with IGF-1 alone grew and spread more, while cells treated with both IGF-1 and Zyflamend grew and spread less. Zyflamend was also shown to decrease levels of the IGF-1 receptor and androgen receptor in prostate cancer cells.

    Studies of Zyflamend in animal models of cancer have shown the following:

    • Mice implanted with pancreatic tumor cells received either Zyflamend or a control treatment. The mice treated with Zyflamend showed lower levels of cancer survival proteins and higher levels of anticancer activity than mice in the control group.

    • Mice implanted with pancreatic tumor cells received either Zyflamend, gemcitabine, or both. Tumor cells from mice that received the combination of Zyflamend and gemcitabine showed a much greater decrease in tumor growth than tumor cells from mice that received Zyflamend or gemcitabine alone. The findings suggested that Zyflamend may have made the pancreatic tumors more sensitive to treatment with gemcitabine.

  4. Have any clinical trials (research studies with people) of Zyflamend been conducted?

    A report of one patient with high-grade prostatic intraepithelial neoplasia (HGPIN) who received Zyflamend 3 times/ day for 18 months showed that PSA levels were not affected. However, at the end of 18 months of treatment, repeat biopsies of the prostate did not show HGPIN or cancer.

    In a phase I safety study of Zyflamend, patients with HGPIN took Zyflamend (780 mg) 3 times/ day for 18 months with additional dietary supplements (probiotic supplement, multivitamin, green and white tea extract, Baikal skullcap, docosahexaenoic acid, holy basil, and turmeric). Zyflamend and the added dietary supplements were well tolerated and there were no serious side effects. At the end of 18 months of treatment, more than half of patients had benign biopsy results, about one-fourth had HGPIN, and about one in 8 had prostate cancer.

  5. Have any side effects or risks been reported from Zyflamend?

    A phase I safety study of Zyflamend (described above) reported no toxicity or serious side effects. Some of the patients had mild heartburn that went away when Zyflamend was taken with food.

  6. Is Zyflamend approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

    The U.S. Food and Drug Administration has not approved the use of Zyflamend as a treatment for cancer or any other medical condition.

    Zyflamend is available in the United States as a dietary supplement. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.

Other Prostate Health Supplements



Overview

Many widely available dietary supplements are marketed to support prostate health. African Cherry (pygeum africanum) and beta-sitosterol are two related supplements that have been studied as possible prostate cancer treatments.

African Cherry / P. africanum

African cherry or Pygeum africanum is a tree that grows in tropical climates. It is found in a number of African countries including Kenya, Madagascar, Uganda, and Nigeria. Bark from the P. africanum tree was used by African tribes to relieve urinary symptoms and stomach pain. In the 18th century, European travelers learned from South African tribes that P. africanum could treat bladder discomfort and “old man’s disease” (enlarged prostate).

Since 1969, bark extracts from P. africanum have been available as prescription drugs in Europe and have been widely used to treat benign prostatic hyperplasia (BPH). The bark contains a number of compounds including fatty acids and phytosterols (e.g., beta-sitosterol). The bark is processed and purified as an extract.

Laboratory studies and animal studies have shown that two substances in bark extract from P. africanum are active in blocking cells from taking up androgen. The antiandrogen activity found in P. africanum is at a markedly lower concentration than the antiandrogen activity found in flutamide (an anticancer drug).

Beta-Sitosterol

Beta-sitosterol is a plant substance found in P. africanum, saw palmetto, and various nuts, beans, and seeds. It is a type of phytosterol (plant sterol) and has a chemical structure similar to cholesterol. Phytosterols, including beta-sitosterol, limit the amount of cholesterol that can be absorbed from the diet and they are being studied for their potential to protect against cardiovascular disease.

Studies suggest that phytosterols may have anticancer activity, but their exact actions are unknown. Phytosterols may affect immune and hormonal systems or may directly target cell cycles and cause cell death in tumors.

Laboratory studies have shown that certain concentrations of beta-sitosterol markedly slow the growth of human prostate cancer cells and cause cancer cell death.

Changes to This Summary (04/03/2014)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Editorial changes were made to this summary.

About This PDQ Summary



About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about prostate cancer. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change.

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Cancer Complementary and Alternative Medicine Editorial Board.

Clinical Trial Information

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials are listed in PDQ and can be found online at NCI's Web site. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).

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National Cancer Institute: PDQ® Prostate Cancer, Nutrition, and Dietary Supplements. Bethesda, MD: National Cancer Institute. Date last modified <MM/DD/YYYY>. Available at: http://cancer.gov/cancertopics/pdq/cam/prostatesupplements/Patient. Accessed <MM/DD/YYYY>.

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General CAM Information

Complementary and alternative medicine (CAM)—also referred to as integrative medicine—includes a broad range of healing philosophies, approaches, and therapies. A therapy is generally called complementary when it is used in addition to conventional treatments; it is often called alternative when it is used instead of conventional treatment. (Conventional treatments are those that are widely accepted and practiced by the mainstream medical community.) Depending on how they are used, some therapies can be considered either complementary or alternative. Complementary and alternative therapies are used in an effort to prevent illness, reduce stress, prevent or reduce side effects and symptoms, or control or cure disease.

Unlike conventional treatments for cancer, complementary and alternative therapies are often not covered by insurance companies. Patients should check with their insurance provider to find out about coverage for complementary and alternative therapies.

Cancer patients considering complementary and alternative therapies should discuss this decision with their doctor, nurse, or pharmacist as they would any therapeutic approach, because some complementary and alternative therapies may interfere with their standard treatment or may be harmful when used with conventional treatment.

Evaluation of CAM Approaches

It is important that the same rigorous scientific evaluation used to assess conventional approaches be used to evaluate CAM therapies. The National Cancer Institute (NCI) and the National Center for Complementary and Alternative Medicine (NCCAM) are sponsoring a number of clinical trials (research studies) at medical centers to evaluate CAM therapies for cancer.

Conventional approaches to cancer treatment have generally been studied for safety and effectiveness through a rigorous scientific process that includes clinical trials with large numbers of patients. Less is known about the safety and effectiveness of complementary and alternative methods. Few CAM therapies have undergone rigorous evaluation. A small number of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that may help patients feel better and recover faster. One example is acupuncture. According to a panel of experts at a National Institutes of Health (NIH) Consensus Conference in November 1997, acupuncture has been found to be effective in the management of chemotherapy-associated nausea and vomiting and in controlling pain associated with surgery. In contrast, some approaches, such as the use of laetrile, have been studied and found ineffective or potentially harmful.

The NCI Best Case Series Program, which was started in 1991, is one way CAM approaches that are being used in practice are being investigated. The program is overseen by the NCI’s Office of Cancer Complementary and Alternative Medicine (OCCAM). Health care professionals who offer alternative cancer therapies submit their patients’ medical records and related materials to OCCAM. OCCAM conducts a critical review of the materials and develops follow-up research strategies for approaches deemed to warrant NCI-initiated research.

Questions to Ask Your Health Care Provider About CAM

When considering complementary and alternative therapies, patients should ask their health care provider the following questions:

  • What side effects can be expected?
  • What are the risks associated with this therapy?
  • Do the known benefits outweigh the risks?
  • What benefits can be expected from this therapy?
  • Will the therapy interfere with conventional treatment?
  • Is this therapy part of a clinical trial?
  • If so, who is sponsoring the trial?
  • Will the therapy be covered by health insurance?

To Learn More About CAM

National Center for Complementary and Alternative Medicine (NCCAM)

The National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health (NIH) facilitates research and evaluation of complementary and alternative practices, and provides information about a variety of approaches to health professionals and the public.

NCCAM Clearinghouse
Post Office Box 7923 Gaithersburg, MD 20898–7923
Telephone: 1–888–644–6226 (toll free) 301–519–3153 (for International callers)
TTY (for deaf and hard of hearing callers): 1–866–464–3615
Fax: 1–866–464–3616
E-mail: info@nccam.nih.gov
Web site: http://nccam.nih.gov

CAM on PubMed

NCCAM and the NIH National Library of Medicine (NLM) jointly developed CAM on PubMed, a free and easy-to-use search tool for finding CAM-related journal citations. As a subset of the NLM's PubMed bibliographic database, CAM on PubMed features more than 230,000 references and abstracts for CAM-related articles from scientific journals. This database also provides links to the Web sites of over 1,800 journals, allowing users to view full-text articles. (A subscription or other fee may be required to access full-text articles.) CAM on PubMed is available through the NCCAM Web site. It can also be accessed through NLM PubMed bibliographic database by selecting the "Limits" tab and choosing "Complementary Medicine" as a subset.

Office of Cancer Complementary and Alternative Medicine

The NCI Office of Cancer Complementary and Alternative Medicine (OCCAM) coordinates the activities of the NCI in the area of complementary and alternative medicine (CAM). OCCAM supports CAM cancer research and provides information about cancer-related CAM to health providers and the general public via the NCI Web site.

National Cancer Institute (NCI) Cancer Information Service

U.S. residents may call the NCI Cancer Information Service toll free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 am to 8:00 pm. A trained Cancer Information Specialist is available to answer your questions.

Food and Drug Administration

The Food and Drug Administration (FDA) regulates drugs and medical devices to ensure that they are safe and effective.

Food and Drug Administration
5600 Fishers Lane
Rockville, MD 20857
Telephone: 1–888–463–6332 (toll free)
Web site: http://www.fda.gov/

Federal Trade Commission

The Federal Trade Commission (FTC) enforces consumer protection laws. Publications available from the FTC include:

  • Who Cares: Sources of Information About Health Care Products and Services
  • Fraudulent Health Claims: Don’t Be Fooled
Consumer Response Center
Federal Trade Commission
CRC-240
Washington, DC 20580
Telephone: 1-877-FTC-HELP (1-877-382-4357) (toll free)
TTY (for deaf and hearing impaired callers): 202-326-2502
Web site: http://www.ftc.gov/