Life Extension Update Exclusive
Fatty fish consumption associated with reduced kidney cancer risk
A report published in the September 20, 2006 issue of the Journal of the American Medical Association (JAMA) revealed that women who ate more fatty fish had a lower risk of the common form of kidney cancer known as renal cell carcinoma (RCC). Renal cell carcinoma affects the functional tissue of the kidney, and comprises over 80 percent of kidney cancers. Previous studies that looked at total fish consumption, but not fatty fish consumption, had failed to find a significant association with a reduced risk of major cancers or renal cell carcinoma.
Alicja Wolk, DMSc, of the Karolinska Institutet, Stockholm, Sweden and colleagues utilized data from 61,433 women participating in the Swedish Mammography Cohort who had no history of a cancer diagnosis upon enrollment. Food questionnaires administered between 1987 and 1990, and again in 1997 were analyzed for fatty fish (salmon, herring, sardines, and mackerel), lean fish, and seafood intake.
Over an average 15.3 years of follow-up, 150 cases of renal cell carcinoma were diagnosed. While no association was found between renal cell carcinoma risk and lean fish or seafood consumption, women who initially reported eating fatty fish at least once per week had a 44 percent lower risk of the disease than those who ate no fatty fish. When the 36,664 women who completed the second questionnaire were examined, consistent consumption of fish, defined as at least one to three times per month, was associated with a 74 percent lower risk of renal cell carcinoma compared to those who consistently did not eat fatty fish.
"Our results support the hypothesis that frequent consumption of fatty fish may lower the risk of RCC possibly due to increased intake of fish oil rich in eicosapentaenoic acid and docosahexaneoic acid as well as vitamin D," the authors write. "Our results, however, require confirmation because this is the first epidemiological study addressing this issue," they conclude.
And in another study, published online on September 15, 2006 in the International Journal of Cancer, researchers at the Moores Cancer Center at University of California, San Diego demonstrated an association between latitudes with reduced sunlight exposure and an increased risk of kidney cancer. Because ultraviolet B radiation triggers the synthesis of vitamin D3 in the body, a deficiency of the vitamin could be a culprit in increased kidney cancer risk.
"Kidney cancer is a mysterious cancer for which no widely accepted cause or means of prevention exists, so we wanted to build on research by one of the co-authors, William Grant, and see if it might be related to deficiency of vitamin D," stated professor of Family and Preventive Medicine in the UCSD School of Medicine and coauthor Cedric Garland, Dr PH.
In addition to reduced sunlight, greater intake of calories from animal sources was also found to be independently associated with increased kidney cancer risk in this study.
The need for more vitamin D
Dr. Reinhold Vieth, MD of the University of Toronto provides convincing evidence that vitamin D deficiency is widespread particularly in northern countries. He is also adamant that currently accepted RDAs (Recommended Daily Allowances) are totally inadequate to prevent osteoporosis and osteomalacia. He points out that total-body sun exposure easily provides the equivalent of 10,000 IU of vitamin D a day and that this amount is what the human race originating in Africa was originally accustomed to. With our current, officially-sanctioned phobia about sun exposure most people expose only their face and hands to the sun on a regular basis and as a result become woefully deficient. The use of sunscreens prevents the formation of any vitamin D at all and makes matters even worse. A vitamin D deficiency is not only heavily implicated in osteoporosis, but has also been linked to breast cancer, ovarian cancer, prostate cancer, and colon cancer. Recent research has shown that a vitamin D intake of 1300 to 3800 IU/day helps prevent multiple sclerosis and that MS is more prevalent among people deficient in vitamin-D. Dr. Vieth recommends a minimum vitamin D intake from supplements of 800-1000 IU/day and feels that a more optimum intake from sunlight and diet would be 4000 IU/day. He also states that numerous studies have shown that daily intakes as high as 10,000 IU are safe (in the absence of sunshine).
Christopher Wiechert, C.N.C.
Christopher Wiechert's Healthblogger is for educational or informational purposes only, and is not intended to diagnose or provide treatment for any condition. If you have any concerns about your own health, you should always consult with a healthcare professional. If you decide to use this information on your own, it's your constitutional right, but I assume no responsibility.
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