The pomegranate is a round shrub or small tree native to the Middle East and Asia that produces a pomegranate fruit characterized by a distinctive leathery outer rind and juicy seeds surrounded by white, spongy tissue. Extracts of this reddish fruit (Punica granatum) have been the subject of much research for their anti-inflammatory, antioxidant, and anticancer properties. Recently, several studies have emerged concerning pomegranate and prostate cancer.
Test-tube studies have shown that pomegranate extracts can slow the reproduction of prostate cancer cells and encourage the cells to commit suicide, a process called apoptosis. (Seeram 2005; Albrecht 2004) Other test-tube and animal studies have indicated that ingredients in pomegranate extracts called ellagitannins can hinder the growth of new blood vessels, which are necessary to nourish prostate tumors. (Sartippour 2008)
In a 2010 study from the University of Quebec, researchers exposed human prostate cancer cells to 13 compounds present in pomegranates and found that four—epigallocatechin gallate, delphinidin chloride, kaempferol, and punicic acid, inhibited cell growth stimulated by dihydrotestosterone (DHT). In particular, punicic acid, the main constituent of pomegranate seed, inhibited cell growth. (Gasmi 2010)
Researchers at the University of California, Riverside, reported that they identified the components of pomegranate juice that are responsible for the fruit’s beneficial effects. They found that pomegranate juice inhibits the activity of a protein in bone marrow that induces cancer cells to spread to bone. According to the study’s authors, who presented their findings at the annual meeting of the American Society for Cell Biology in December 2010, modification of the active components could make them even more effective against prostate cancer.
A University of California, Los Angeles (UCLA) study evaluated the effects of pomegranate in men who had had surgery or radiation for prostate cancer but whose PSA levels had risen, which indicated that the cancer may be returning. When the study began the men’s average PSA level doubled every 15 months. The men were then given 8 ounces of pomegranate juice to drink daily. By the end of the study, it was taking 54 months for the average PSA level to double, cancer cell apoptosis had increased by 17 percent, and proliferation of cancer cells had declined by 12 percent. These findings suggested that the disease progression had slowed, and that pomegranate was involved. (Pantuck 2006) In another UCLA study, scientists noted that pomegranate polyphenols inhibited gene expression in androgen-independent prostate cancer cells. (Hong 2008)
Pomegranate has also demonstrated evidence it can be helpful in treating erectile dysfunction. In one animal study, investigators compared pomegranate juice, red wine, green tea, and several berry juices and found that pomegranate juice showed the most antioxidant capacity. Long-term intake of pomegranate juice improved erectile function and prevented erectile tissue fibrosis. (Azadzoi 2005) A study of men with mild to moderate erectile dysfunction found that pomegranate juice intake resulted in some improvement in erectile function, although the improvement was not significant. (Forest 2007)
One animal study conducted at the Turkish Firat University explored the effect of pomegranate juice on sperm quality and testosterone levels in rats compared with a control group not fed the juice. The treated animals were fed pomegranate juice daily for seven weeks. Researchers found that pomegranate juice increased the production of antioxidants in the sperm, which improved its quality, and also resulted in a slight increase in testosterone levels, which they attributed to the antioxidant effect of the juice. (Turk 2008)
It has also been suggested that the antioxidant and anti-inflammatory properties of pomegranate may help in the prevention and treatment of BPH and prostatitis.
For men who have prostate cancer, the suggested dose is 8 ounces of juice daily. (University of Maryland) So far, no one has done a scientific study to determine how a pomegranate supplement compares with 8 ounces of pomegranate juice or eating the fruit.
Azadzoi KM et al. Oxidative stress in arteriogenic erectile dysfunction: prophylactic role of antioxidants. J Urol 2005; 174:386-93
Albrecht M, et al. 2004 Pomegranate extracts potently suppress proliferation, xenograft growth, and invasion of human prostate cancer cells. JMedic Food 2004; 7:274-83
Forest CP et al. Efficacy and safety of pomegranate juice on improvement of erectile dysfunction in male patients with mild to moderate erectile dysfunction: a randomized, placebo-controlled, double-blind crossover study. Intl J Impot Res 2007; doi: 10.1038/sj.ijir.3901570
Gasmi J, Sanderson JT. Growth inhibitory, antiandrogenic, and pro-apoptotic effects of punicic acid in LNCaP human prostate cancer cells. J Agric Food Chem 2010 Nov 10
Hong MY et al. Pomegranate polyphenols down-regulate expression of androgen-synthesizing genes in human prostate cancer cells overexpressing the androgen receptor. J Nutr Biochem 2008; 19:848-55
Pantuck AJ et al. Phase II study of pomegranate juice for men with rising prostate-specific antigen following surgery or radiation for prostate cancer. Clin Cancer Res 2006; 12(13): 4018-26.
Sartippour MR et al. Ellagitannin-rich pomegranate extract inhibits angiogenesis in prostate cancer in vitro and in vivo. Int J Oncol 2008 Feb; 32(2):475-80.
Seeram NP et al. In vitro antiproliferative, apoptotic and antioxidant activities of punicalagin, ellagic acid and a total pomegranate tannin extract are enhanced in combination with other polyphenols as found in pomegranate juice. J Nutr Biochem 2005 Jun; 16(6):360-67.
Turk G et al. Effects of pomegranate juice consumption on sperm quality, spermatogenic cell density, antioxidant activity and testosterone level in male rats. Clin Nutr 2008 Apr; 27(2): 289-96
University of Maryland Medical Center, http://www.umm.edu/altmed/articles/pomegranate-002881.htm