Questions and Answers About Pomegranate
- 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.
- 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.
- How is pomegranate administered or consumed?
- Have any preclinical (laboratory or animal) studies been conducted using pomegranate?
- 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.
- 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 phase II 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 with no adverse effects.
- Have any side effects or risks been reported from pomegranate?
- 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.
- Is pomegranate approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?
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.