Pomegranate May Prevent and Slow Prostate Cancer
Prostate cancer is the most common malignancy and second leading cause of cancer death among American men.16 Scientists are rapidly learning that the growth of prostate cancer can be prevented by proper dietary supplementation, especially with antioxidant and anti-inflammatory agents.17-19 Several of the pure chemical compounds found in pomegranate—including ellagic acid and luteolin—work together synergistically to inhibit cancer cell growth.20-22
Results of a recent laboratory study underscore the dramatic protective effects of antioxidants in pomegranate.23 When human prostate cancer cells were exposed to pomegranate fruit extract, they immediately began to produce substances that led to their own death. This process of programmed cell death, called apoptosis, is vital to the body’s normal regulation of potentially cancerous tissue. In another experiment, oral administration of pomegranate fruit extract greatly inhibited tumor growth in mice.23 This correlated with a dramatic decline in blood levels of prostate-specific antigen (PSA), which doctors use to monitor prostate cancer progression. This led the study authors to conclude that pomegranate juice may be useful in preventing prostate cancer, as well as in slowing the progression of existing prostate cancer.22,24
An even more detailed study of the effects of various pomegranate components was conducted by German investigators, who were interested in finding ways to slow or reverse prostate cancer growth.25 The German scientists studied several different types of prostate cancer, including both those that are dependent on androgens (male hormones) and those that are not. Rates of growth and reproduction were slashed in all prostate cancer cell types tested, regardless of whether the pomegranate extract was derived from the seeds, juice, or oils of the fruit.
Moreover, the researchers determined that the pomegranate extracts worked via several mechanisms simultaneously to slow cancer cell growth—in sharp contrast to chemotherapy drugs, which work through only a single mechanism. Over time, cancer cells can develop resistance to chemotherapy (that is, failure to respond to a previously effective agent), leading some scientists to propose that anti-cancer agents that work by multiple mechanisms may offer greater treatment efficacy.
Finally, the German investigators were able to show that the cell-killing and growth-inhibiting effects of the pomegranate extracts were limited to cancerous cells—normal prostate cells were much less significantly affected.25 If these findings hold true in men with prostate cancer, pomegranate may help kill cancerous cells while leaving healthy tissues intact.
Prostate tumor confined to prostate gland.
Convincing data from human clinical trials now support pomegranate extract’s ability to fight prostate cancer. Doctors at UCLA investigated whether pomegranate could slow the rate of cancer progression in men who had undergone surgery or radiation treatment for prostate cancer.26 The subjects drank 8 ounces of pomegranate juice daily (providing 280-375 mg of punicalagins), and their PSA doubling times were compared before and after treatment. A short PSA doubling time indicates rapid growth of residual prostate cancer, while a longer doubling time signifies slower tumor growth. Daily intake of pomegranate juice increased mean PSA doubling time from 15 months at baseline to 54 months in 80% of the men post-treatment—a nearly fourfold jump. Even more remarkable, when blood serum from these men was obtained after treatment and applied directly to prostate cancer cells in culture, cell growth rates plummeted and cell death rates soared. The cells also increased their ability to withstand oxidative stress.
In sum, these important findings suggest that pomegranate may help prevent the occurrence of prostate cancer, while slowing the growth and spread of existing prostate cancers.
Promising New Applications for Pomegranate
Preliminary research findings suggest that, in addition to its potentially lifesaving benefits for heart, diabetes, and cancer patients, pomegranate may confer a multitude of other health-promoting effects in the body, from alleviating the pain and discomfort of arthritis to supporting optimal brain, dental, skin, and liver health.
Inflammation destroys joint-cushioning cartilage, inflicting tremendous pain and disability on the estimated 21 million Americans who suffer from osteoarthritis. By severely curtaining physical activity, osteoarthritis can initiate a vicious cycle in which its sufferers become ever more sedentary (and often overweight), triggering additional health problems.27
Pomegranate’s ability to break the cycle of inflammation and tissue damage28 spurred scientists at Case Western University to explore whether it could protect joint cartilage from inflammation in patients with osteoarthritis.29 In an in-vitro experiment, they first treated cartilage from osteoarthritis patients with pomegranate fruit extract, and then stimulated the tissue with interleukin-1 beta, a potent inflammatory mediator. The scientists then measured the extent of cartilage destruction and production of inflammatory molecules in the tissue samples.
Pretreatment with pomegranate fruit extract inhibited enzymes that break down cartilage, and sharply reduced the volume of inflam-matory products released from the tissue. The researchers concluded that pomegranate fruit extract “may inhibit cartilage degradation in osteoarthritis and may also be a useful nutritive supplement for maintaining joint integrity and function.”
In 2006, scientists at California’s Loma Linda University reported groundbreaking research on a potential role for pomegranate juice in averting Alzheimer’s disease.30
The researchers knew that antioxidant polyphenols from other fruits and vegetables have protected brain cells in various animal models,31 and that pomegranate juice itself had been shown to limit brain damage in mice that suffered experimentally induced strokes.32 Since oxidation is thought to produce the Alzheimer’s protein known as amyloid beta, the Loma Linda team decided to test their hunch that pomegranate juice could put a stop to amyloid-beta accumulation. They also explored the more radical notion that pomegranate juice alone would have a detectable effect on cognitive abilities, using a “water maze task” that tests animals’ ability to accurately and quickly make their way out of a water-filled labyrinth.
The researchers’ intuition was rewarded, as mice with Alzheimer’s-like disease that were given pomegranate juice from 6 to 13 months of age accumulated about 50% less amyloid beta than control mice. The juice-treated animals out-performed control animals, exiting the water maze 35% faster than the control group.30 The authors declared their study to be “the first to show beneficial effects (both behavioral and neuropathological) of pomegranate juice in an animal model of Alzheimer’s disease.”