For reliable dietary advice, most nutritionists agree, look to the food pyramid. But when it comes to advice about milk and dairy, the question is: Which pyramid?
The official food pyramid comes from the U.S. Department of Agriculture. It incorporates the recommendations of top ranking nutrition scientists from around the country. But other groups, disagreeing with some aspects of the USDA’s recommendations, have constructed alternative pyramids. One of the most influential is the food pyramid created by researchers at the Harvard School of Public Health. And one of the big differences between its advice and the USDA’s relates to milk and dairy products.
In 2005, the USDA’s dietary guidelines increased the recommended servings of milk from two to three cups a day. The latest guidelines, released in 2010, repeat that advice. They specifically urge Americans to get more fat-free or low-fat milk and related dairy products.
According to Harvard’s food pyramid, on the other hand, milk isn’t an essential part of a healthy diet -- and may pose risks.
The Case for Milk and Dairy
The USDA’s recommendations are based on the fact that milk is a prime source for three important nutrients: calcium, potassium, and vitamin D (which is added to fortified milk.)
“Milk contains a big package of nutrients that are especially important to bone health,” says Connie M. Weaver, PhD, who directs the nutrition department at Purdue University. “People who don’t drink milk tend to be deficient in them. So it makes good sense to encourage people to consume dairy products.”
Milk is also a good source of potassium -- another compelling reason the USDA committee increased the recommended servings from two to three in 2005, according to Penny Kris-Etherton, PhD, RD, professor of nutrition at Pennsylvania State University, who served on the committee.
Too much sodium and too little potassium together are risk factors for high blood pressure. Unfortunately, most Americans get too much salt and don’t get enough potassium. Milk isn’t the only source, to be sure. Many vegetables and fruits are also rich in potassium. But according to Kris-Etherton, experts hesitated to increase the recommended servings of vegetables, which were already more than most Americans were eating.
“Short of encouraging people to eat more vegetables, we thought the best way to ensure adequate potassium was to recommend low-fat milk,” she tells WebMD.
The Case Against Milk and Dairy
Not everyone thinks that was a good idea. Indeed, experts at the Harvard School of Public Health have labeled the milk recommendations a “step in the wrong direction.” One the most prominent critics is Walter Willett, MD, PhD, professor of epidemiology and head of the nutrition department at the Harvard School of Public Health.
“One of the main arguments for USDA recommendations is that drinking milk or equivalent dairy products will reduce the risk of fractures. But in fact there’s very little evidence that milk consumption is associated with reduced fractures,” Willett tells WebMD.