While total calcium and vitamin D intake does not appear to impact the risk of prostate cancer, consuming your 3-a-day of dairy in the form of low fat or skim milk may actually increase the risk of malignancy, according to two studies recently published in the American Journal of Epidemiology …

 

Past research had indicated a potential link between dietary calcium and dairy product intake and prostate cancer, though the supporting evidence was not clear.  In order to explore this topic further, these two large studies were launched.

The first was led by Dr. Song-Yi Park, from the University of Hawaii in Honolulu.  His group conducted a Multiethnic Cohort Study of 82,483 men between the ages of 45 and 75, from 1993 to 2002.  During that time, 4,404 of the men developed prostate cancer.  No association was found between calcium and vitamin D and prostate cancer, regardless of if the source was via supplements or dietary intake. However, consumption of low fat and nonfat milk was related to an increased risk, while whole milk correlated with a decreased risk of total prostate cancer.  The study does suggest that an association with milk consumption may vary by fat content, particularly for early forms of this cancer.

Another study, led by Dr. Yikyung Park, from the National Cancer Institute at the National Institutes of Health (NIH) in Bethesda, Maryland, produced similar results.  Their research was conducted between 1995 and 2001, following 293,888 men.

Similar to the findings out of the University of Hawaii, skim milk was linked with advanced prostate cancer. In contrast, calcium intake from non-dairy foods was actually tied to a reduced risk of non-advanced prostate cancer.

If you aren’t interested in increasing your fat and calorie intake, but have concerns of prostate cancer risk, then perhaps green tea would be the best beverage of choice.  A third study published in December, found that men who drank five or more cups a day may cut their risk of developing advanced prostate cancer in half, when compared to those men who drank less than one cup a day.

Further studies will be required to solidify any of these possible connections.

SOURCES:
American Journal of Epidemiology, December 1, 2008.
Reuters: Nonfat Milk Linked to Prostate Cancer

According to the enormous 12-year Harvard study of 77,761 female nurses, as published in the American Journal of Public Health (1997, volume 87):  “…women consuming greater amounts of calcium from dairy foods had significantly increased risks of hip fractures, while no increase in fracture risk was observed for the same levels of calcium from nondairy sources.”

 

Wait a minute, dairy products could actually be a cause of hip fractures from osteoporosis? This landmark study has risen more than a few eyebrows in the medical community. Although this is a giant study in its own right, it certainly does not stand alone in the evidence for a dairy-free lifestyle.

In a review of 34 published studies in 16 different countries, researchers at Yale University discovered that the countries with the highest rates of osteoporosis, including the United States, England, Sweden, and Finland, were coincidentally also the highest consumers of dairy products. As further proof, countries with historically low rates of osteoporosis and hip fracture, such as China, are seeing a proportionate increase in the incidence of osteoporosis with the adoption of Westernized dietary habits.

But, how can this be…according to the USDA, milk is one of our major food groups? The answer is not completely clear, but there are a couple of strong theories circulating in the scientific community. High dairy intake provides a high level of animal protein, which in turn is high in sulfur-containing amino acids. The body buffers the effects of these amino acids by releasing calcium from the bones, and excreting it from the body. In addition, animal foods, particularly milk, contain very high levels of phosphorous, which may interfere with calcium absorption.

The tides are turning on the osteoporosis front. Keeping strong bones may depend more on preventing calcium loss than on increasing calcium intake. For this reason, many renowned researchers are changing their calcium vote from milk to plant sources such as vegetables, fruits, and nuts.