For years, low-fat cow's milk has been enthusiastically promoted as the perfect health drink, providing adults with 'essential' vitamins and minerals, but without the so-called heart-unhealthy fat found in whole milk.
However, new research suggests that low-fat milk could actually be doing
us more harm than good, increasing the risk of serious health problems-from infertility to prostate cancer.
Worse, scientists hypothesize that stripping the fat from milk-to make the drink supposedly healthier-could be the very reason for its toxic effects.
Two major studies have discovered that a high-dairy diet increases the risk of prostate cancer-but the real culprit could be the multibillion-pound low-fat industry built upon the belief that animal fats cause heart disease (see WDDTY vol 17 no 11). Scientists now suspect that the real problem is processed, low-fat dairy foods that have been stripped of their protective and health-giving qualities.
The two separate studies-both published in February-have confirm-ed growing suspicions of a link between dairy and prostate cancer. One is the CLUE II study, involving nearly 4000 men in Washington County, Maryland; this found that those who consumed five or more servings a week of dairy foods were more likely to suffer from prostate cancer than those who ate a serving of one or less (Cancer Causes Control, 2007; 18: 41-50).
Similarly, the other study, an analysis of over 29,000 Finnish men taking part in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study), found that the more dairy consumed, the higher the risk of prostate cancer (Int J Cancer, 2007 Feb 2; Epub ahead of print).
These findings deal a double blow to the dairy industry, yet the link between dairy and prostate cancer is not new. As far back as 1975, scientists noted a strong correlation between milk intake and prostate cancer deaths (Am J Clin Nutr, 2005; 81: 1147-54).
Since then, many more reports have confirmed an increased cancer risk from dairy foods-particularly milk, the most common form of dairy consumed.
Initial explanations for such an association blamed saturated dairy fat (Salud Publ Mex, 1997; 39: 298-309), but mounting evidence suggests that the truth could be quite the opposite: that removing the fat from milk may be responsible for the carcinogenic effects.
An American prospective study involving more than 3600 men and 10 years of follow-up-for the first National Health and Nutrition Examination Epidemiologic Follow-up Study (NHEFS)-found that those with the highest intakes of dairy were more than twice as likely to develop prostate cancer than men with the lowest intakes.
However, when the researchers looked at the individual dairy products consumed, they found that the risk was higher only with low-fat milk-and not for whole milk or any other dairy. In fact, whole milk had a slight-albeit statistically not significant-protective effect (Am J Clin Nutr, 2005; 81: 1147-54).
Harvard's Physicians' Health Study arrived at a similar conclusion. This study, involving over 20,000 men and 11 years of follow-up, found that the increased risk of prostate cancer associated with dairy intake was attributable primarily to skimmed milk. Of the five dairy foods investigated (milk in cold breakfast cereal, whole milk, skimmed milk, cheese and ice cream), only skimmed milk showed a significantly positive relationship when men consumed one or more servings per day (Am J Clin Nutr, 2001; 74: 549-54).