Milk: Five Myths and Truths

Milk used to be considered a "perfect food"--indeed it is very nutritious. In recent years, however, "cow's milk is for calves" has become a rallying cry for several groups, which claim that milk is nothing less than a "deadly poison." If you believe these groups, milk is behind nearly all our major diseases. Here are some of the claims being made about milk and dairy products and the facts.


Claim: Dairy products increase the risk of heart disease.

Facts: If you consume lots of whole milk and cheese, you're likely to raise your blood cholesterol levels. That's true, however, of any foods rich in saturated fat and cholesterol. Milk's opponents talk as if all milk is still whole milk. But more and more dairy products these days are nonfat or low-fat, and thus do not raise cholesterol levels significantly. In fact, there's some evidence that certain substances in milk may help lower cholesterol somewhat. (However, with whole milk, this effect is probably overwhelmed by the cholesterol-boosting effect of the fat.) And since milk is rich in calcium and magnesium, it can help reduce the risk of hypertension.

Milk opponents often quote a paper in Alternative Medicine Review that indicted milk, even nonfat milk, as a cause of heart disease. But that article was simplistic and misleading. It found an association between milk consumption and heart disease in population studies from 32 countries, but the data did not allow the researcher to take into consideration many of the other factors that can affect the risk of heart disease. Nor do the data specify what kind of milk (full-fat vs. lower-fat) was consumed in the various countries.


Claim: Dairy products increase the risk of ovarian cancer.

Facts: A few studies have suggested that there's a link between lactose (milk sugar) and/or galactose (a related sugar) and ovarian cancer, while others have found no connection. However, a well-done study in the American Journal of Epidemiology refuted this claim. It found that women with ovarian cancer had consumed less, not more, of these milk sugars than healthy women.


Claim: Dairy products boost the risk of cancer in general.

Facts: Milk is not the problem, but rather total fat intake. For instance, a high fat intake may increase the risk of lung and colon cancer. But at the same time some studies have found that low-fat milk reduces the risk of lung cancer. In fact, animal studies have shown that compounds in milk may suppress cancer development. In addition, there's some evidence that dairy products reduce the risk of colon cancer. Both calcium and vitamin D (added to milk) may help protect colon cells.


Claim: Dairy products actually increase the risk osteoporosis.

Facts: This notion is based in large part on the fact that in certain countries, such as China, where dairy products are rarely consumed and calcium comes primarily from green vegetables, the rate of osteoporosis (weakened bones) is low. In fact, the studies present contradictory findings: many show that high calcium intake (mostly from dairy products, and particularly in early adulthood) does lead to stronger bones, but others find that dairy or calcium intake does not lower the risk of hip fractures. One possible problem is that dairy products are rich in protein, and a high protein intake slightly increases calcium excretion in urine, which might reduce bone density. The high levels of calcium in dairy products should, however, more than offset any effect their protein may have on your bones. Genetics also plays a big role. Most experts continue to recommend dairy products (along with exercise and, if necessary, calcium supplements) as the best way to reduce the risk of osteoporosis.


Claim: People who have problems digesting lactose can eat or drink no dairy products.

Facts: Many people who believe they can't digest any lactose (milk sugar) without bloating and discomfort are not really lactose-intolerant. Moreover, studies show that even those who truly are lactose-intolerant are able to digest a cup or two of milk a day, if consumed at meals, with few if any symptoms. Beyond that, they can turn to lactose-reduced milk (store-bought or homemade).


The milky way: Milk and other dairy products are the best sources of calcium, which not only keeps bones strong, but also may help prevent hypertension, heart disease, colon cancer, and possibly even diabetes. They are also important sources of other nutrients, notably riboflavin, vitamins A and D, and several other minerals. Whole milk and products made from it are, of course, rich in fat. That's why children over the age of two, as well as adults, should rely on nonfat or low-fat (1%) milk, yogurt, and other dairy products.