Milk: Does it do a body good or not?
The evidence doesn't back up claims that dairy products cause all kinds of ills
By JANE E. BRODY
New York Times
Last Updated: Oct. 8, 2000
"Got milk?" cries the National Dairy Council, seeking to reverse or at least stem a half-century decline in per-capita consumption of this nutrient-packed beverage.
"Got beer?" countered the Physicians Committee for Responsible Medicine, a non-profit organization that promotes milk-free vegetarian diets and in 1992 denounced the feeding of cows' milk to children.
Although the committee dropped its counterattack when the United States Department of Agriculture decided to add soy milk as a "dairy" option in the Dietary Guidelines for Americans, the milk wars continue to rage. Hardly a month passes without another accusation hurled at milk as less than an ideal food.
Among recent claims: Milk can cause juvenile diabetes, heart disease, cancer, digestive disorders, ear infections, mucus in the throat and, in infants, allergies, colic and iron deficiency anemia. The Physicians Committee has even accused calcium-rich milk of increasing, rather than decreasing, the risk of osteoporosis.
In Wisconsin, animal rights activists have also entered the fray, among other things reviving the old "Got beer?" slogan, and taking it one further with a billboard of New York Mayor Rudolph Giuliani and the caption "Got prostate cancer?"
The popular claim that "cows' milk is for calves," not people, begs an intriguing dietary question: On what grounds can it be said that any cultivated food - be it wheat, rice, potatoes, broccoli, carrots, chicken or pork - was meant to be eaten by people? Humans began as hunter-gatherers, eating whatever they could find that grew naturally. No edible specifically evolved to feed people. Rather, people learned to cultivate edible plant and animal foods to assure a more constant food supply.
Here is what has been said and what is actually known about milk's relationship to health:
Heart disease
If milk (and other dairy products) are consumed in large amounts in their whole-fat state, then they may raise blood levels of cholesterol and contribute to heart disease. But supermarkets are now bursting with low-fat and non-fat dairy options, including liquid milk, yogurt, ice cream, cheese and fat-free "half-and-half." After the age of 2, there is no reason not to switch to these heart-saving low-fat alternatives, especially since certain substances in milk may help to lower cholesterol.
Cancer
A few studies have suggested a link - but others have found no link - between the sugars in milk and ovarian cancer. But the most carefully done study to date found that women who developed ovarian cancer actually drank less milk than those who remained free of this cancer. While the high-fat content of whole milk and other full-fat dairy products may promote certain cancers, recent studies have indicated that components of low-fat and fat-free dairy products can reduce the risk of cancers of the breast, lungs and colon.
Diabetes
Type 1 diabetes, as juvenile or insulin-dependent diabetes is now called, is an autoimmune disease, and there is some evidence that people who develop it tend to have high levels of antibodies in their blood to the proteins in cows' milk. The risk, if there is a real one, of developing this form of diabetes seems to be related to the consumption of unmodified cows' milk in infancy by susceptible people.
Infant formulas are heat-treated in a way that modifies these proteins to reduce the risk that babies will develop antibodies to them. Also contributing to a lower risk associated with infant formula is the fact that the amount of protein in formula more closely resembles that of breast milk, which has less than half the protein in cows' milk.
The American Academy of Pediatrics recommends that infants in their first year not be given unmodified cows' milk or products like ice cream or yogurt made from unmodified cows' milk. Waiting to introduce cows' milk until an infant's digestive system is more fully matured will reduce the risk of milk allergy and possibly other allergies as well. Incidentally, allergic reactions to milk, which most often develop in infancy, are nearly always outgrown by the elementary grades.
Mucus in the throat
Whole milk, because of its consistency, can coat the mouth and throat temporarily and create the sensation of thickened saliva or mucus. But a blind study in Australia that included people who believed the milk-mucus relationship found no difference in reports of mucus in the throat among those who ate chocolate-disguised cows' milk or soy milk. While professional singers, actors or public speakers may refrain from milk shortly before performances, there is no reason for them to do so at other times or for others to avoid milk for this reason. If milk-induced mucus seems to bother you, try switching to non-fat milk.
Osteoporosis
It is true that in most Asian countries, where little or no dairy products are consumed, there is a much lower incidence of osteoporosis than in the United States. But it is also true that Asians eat a lot more calcium-rich vegetables and a lot less protein than Americans do. The excess protein consumed by most Americans actually removes calcium from the body. Asians also get a lot more physical exercise and consume less cola, which can impede the use of calcium.
Milk and other dairy products are by far the leading sources of bone-building nutrients - primarily calcium and vitamin D - in the American diet. Although milk contains protein, the ratio of calcium to protein in milk is high enough to favor bone development, not the bone loss suggested by the Physicians Committee.
Digestive problems
About one-quarter of Americans develop varying degrees of lactose intolerance, an inability to digest the natural sugar in milk, which can result in bloating, flatulence and sometimes diarrhea. The incidence of lactose intolerance is highest in American Indians, African-Americans and people of Eastern European or Asian descent.
But most people with lactose intolerance can drink a glass of milk with meals with few if any symptoms. Also, yogurt with live active cultures (the bacteria produce lactose-digesting enzymes) and hard cheeses (which lose most of the lactose when the curds are formed) are unlikely to cause symptoms. In addition, lactose-reduced dairy products - milk, cottage cheese, even ice cream - are now widely available. Or, you can prepare your own lactose-reduced milk by adding the enzyme lactase (sold as Lactaid drops in pharmacies) to liquid milk and waiting a day to consume it.
In addition to building bones, the calcium and other components in milk may help prevent hypertension (and, thus, heart disease and stroke) and cancers of the breast and colon. Milk is also a good source of other vital nutrients, including vitamins A and D, riboflavin, protein, phosphorus and the trace elements copper, zinc and manganese.
A large national study called DASH has shown that only when a low-fat diet rich in fruits and vegetables is combined with three servings a day of low-fat dairy foods is the diet effective in lowering blood pressure and reducing blood levels of homocysteine, another risk factor for heart disease.
Appeared in the Milwaukee Journal Sentinel on Oct. 9, 2000.
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