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A new clinical study confirms that pomegranate, combined with other polyphenol-rich foods, can significantly reduce prostate enlargement and cancer risk among men.
The new double-blind, placebo-controlled study comes as controversy has emerged after two clinical studies found pomegranate did not improve prostate parameters.
In this most recent study, Cambridge University researchers tested 199 men who were diagnosed with local prostate cancer. The men had an average age of 74 years old. The men were divided into two groups.
After the six months, the placebo group's PSA rose by 78.5% while the treatment group's PSA rose by 14.7% - a difference of 64% and a reduced PSA rise by more than five times. The researchers concluded:
"This study found a significant short-term, favorable effect on the percentage rise in PSA in men managed with active surveillance or watchful waiting prostate cancer following ingestion of this well-tolerated, specific blend of concentrated foods."
Two recent studies question pomegranate
As mentioned, two other recent clinical studies showed pomegranate's beneficial effects upon the prostate may be limited - assuming lower polyphenol levels as found in another recent study.
In one of the studies, Duke University researchers tested 70 men with either a pomegranate supplement or a placebo for four weeks. The researchers found no difference in PSA levels or other clinical parameters between the two groups.
In the other study, a Phase II clinical trial, 102 prostate-cancer patients received either 500 milliliters of a pomegranate juice or 500 ml (about 16 oz) of a placebo drink for four weeks, followed by a 250 ml of each for the next four weeks. There were few differences between the PSA levels or advancement of cancer progression between the two groups.
Could this be related to polyphenol content?
Researchers from Germany's University of Freiburg investigated the pomegranate used in the above research and found, using high-performance liquid chromatography, that the pomegranate blends contained low levels of polyphenols such as ellagic acid and anthocyanins. They also commented that the dosages given in the studies were low:
"The results show that the co-active compounds in the daily dose of the pomegranate blend were far below those previously tested and that the photometric assessment is not reliable for the standardisation of study medications."
Previous clinical research showed efficacy
There have been several studies over the past decade that have shown the ability of pomegranate to reduce prostate PSA rise.
In one, UCLA researchers tested patients after receiving prostate cancer surgery or radiation treatment. The patients were given 8 ounces of a 570 milligram-gallic acid polyphenol pomegranate juice.
The research found that the patients' PSA doubling times significantly increased, from doubling every 15 months at the beginning of the study to doubling every 54 months at the end of treatment. The researchers also found a reduction of 12% in cancer cell proliferation and reduced oxidation levels among the patients.
While this Phase II study did not have a placebo group - as has been lodged against it, the patients' clinical parameters were closely followed and measured before and after the study.
Four 2011 studies – including one from the University of California/Riverside and another from the University of Wisconsin – have showed that pomegranate juice slows the growth and metastasizing of prostate cancer.
These two studies and two other research reviews showed that pomegranate juice stopped prostate cancer cells from growing.
The research from the Department of Cell Biology and Neuroscience at the University of California found that pomegranate juice alters the ability of prostate cancer cells to adhere to tissues and migrate within and outside the prostate. They also found that pomegranate juice alters the cytoskeleton of cancer cells.
Pomegranate juice does this by altering the genes of the cancer cells. Pomegranate alters molecules known as E-cadherin and ICAM-1 (intercellular adhesion molecule 1) within tumor cells. When these are altered, the cancer cells no longer organize and grow within prostate tissue.
The UC researchers also found that pomegranate calmed the inflammatory process by altering the pro-inflammatory cytokines such as IL-6 and IL-1β. This slows cancer cell growth because the tumor cells utilize inflammation processes to expand.
The University of Wisconsin researchers found that mice with prostate cancer that drank pomegranate fruit extract with their water experienced "remarkable tumor growth inhibitory effects" compared to those who drank water only.
Those fed the pomegranate juice with their water had minimal metastases compared to those who drank water without the pomegranate. Among men over 75, prostate cancer is the leading cause of death due to cancer.
Risk factors for prostate cancer include those who drink excessively or are exposed to pesticides, agent orange, tire plant environments, paint, or cadmium.
According to research from Portugal's University of Porto, pomegranate achieves several anti-cancer effects, including cancer prevention, cancer cell retardation and cancer cell death.
The ability to kill cancer cells, they found, is due to its ability to modulate Bcl-2 proteins while increasing the p21 and p27 pathways. They also found that pomegranate inhibits the pro-inflammatory NFκ-B pathway, among others.
They concluded that:
"Anti-cancer effects with the most impressive data have been demonstrated so far in prostate cancer."
Meanwhile, a 2011 study from the USDA's Agricultural Research Service found that pomegranate contains a number of phytonutrients that provide for its antioxidant and anti-inflammatory effects. The USDA researchers found that pomegranate contains polyphenols such as punicalagins, punicalins, gallagic acid, and ellagic acid.
The USDA-ARS study, led by food science researcher Dr. Suzanne Johanningsmeier, a professor at North Carolina State University, also found that pomegranate contains heart-healthy anthocyanins together with a "unique fatty acid profile" within its seed oils. After a review of the human research, they concluded that human studies confirm pomegranate's effects:
"Promising results against cardiovascular disease, diabetes, and prostate cancer have been reported from human clinical trials."
Shortcomings of the Single-bullet Theory
Clinical research often puts a microscope on our perceptions about health. In the case of new clinical research showing dubious results for pomegranate, both studies were fairly short - one only a month long and the other two months. Is a month or two really enough time to reverse or heal effects of up to a half-century of poor dietary choices and activities that eventually reduce immunity and increase inflammation?
The concept of the single-bullet theory is thoroughly embedded into the consciousness of conventional medicine, as doctors try to replace the 'miracle pharmaceutical' concept with a natural food or herb. But this typically backfires, because nature often works slowly and gradually, and typically requires dedication and commitment towards the healing effort.
The first study above reveals that the positive effects of pomegranate may well lie within its polyphenol content. But again, this is not a single-bullet. This is simply a class of compounds within medicinal foods and herbs that provide healing benefits when used appropriately and integrated wisely into the diet.
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