A commentary published last week in the journal JAMA Pediatrics challenges two long-held beliefs: that low-fat milk is more healthful than whole milk and that everybody should consume a minimum of three servings of milk (or its dairy equivalent) daily.
In the commentary, Dr. David Ludwig, a pediatrician at Boston Children’s Hospital, and Dr. Walter Willett, chair of the department of nutrition and epidemiology at the Harvard School of Public Health (two very well-known and respected nutrition scientists), explain why low-fat milk may actually do more harm than good when it comes to keeping our weight in check or protecting our hearts. They also point out that the three-servings-a-day recommendation, which is advocated by the U.S. Department of Agriculture, the American Academy of Pediatrics and most other medical groups, lacks scientific support.
The two doctors are not calling for either children or adults to stop drinking milk. They just think broader and more evidence-based recommendations are needed.
Here are some of their key points:
- Low-fat milk does not help us slim down. Studies involving children, teens and adults have shown that when we substitute reduced-fat milk for whole milk, we do not lose more weight. In fact, we may actually gain weight, perhaps because low-fat products make us feel less full, thus raising the likelihood that we’ll consume more of other foods. “Suppose a child who habitually consumes a cup of whole milk and two 60-kcal cookies for a snack instead had nonfat milk,” write Ludwig and Willett. “Energy intake with that snack would not decrease if that child felt less satiated and consequently ate one more cookie.”
- Low-fat milk does not protect our hearts. We’re also told that low-fat milk is better for us than whole milk because the saturated fat in whole milk raises low-density lipoprotein (LDL) cholesterol, considered a major risk factor for heart disease. “However,” write Ludwig and Willett, “when compared to carbohydrates, saturated fat increases cardioprotective high-density lipoprotein [HDL] cholesterol, leaving the ratio of high-density lipoprotein to total cholesterol relatively unchanged.” Also, low-fat milk may lead us (like the child in the earlier example) to consume more high-glycemic-index foods, which, the two doctors point out, may raise levels of a third blood lipid, triglycerides, to heart-unhealthy levels.
- Current daily milk recommendations are causing children to consume added — and unhealthful — sugars. To entice their children to get enough milk, many schools (and parents) serve chocolate and other flavored sugar-sweetened milks. These drinks make low-fat milk more palatable to young people, Ludwig and Willett point out, but they also contain many extra grams of sugar, “which clearly undermines diet quality, especially in a population with excessive sugar consumption.”
No need for animal milk
Humans have no nutritional need for animal milk, say Ludwig and Willett, and many populations throughout the world do not consume any, yet are quite healthy. Indeed, dairy products are not, the doctors stress, essential for strong bones:
Adequate dietary calcium for bone health, often cited as the primary rationale for high intakes of milk, can be obtained from many other sources. Indeed, the recommended levels of calcium intake in the United States, based predominately on balance studies of 3 weeks or less, likely overestimate actual requirements and greatly exceed recommended intakes in the United Kingdom. Throughout the world, bone fracture rates tend to be lower in countries that do not consume milk compared with those that do. Moreover, milk consumption does not protect against fracture in adults, according to a recent meta-analysis.
How much milk an individual child or adult needs will depend on the overall quality of his or her diet, Ludwig and Willett point out. And nutritional guidelines, they conclude, should reflect that fact.
“Pending further randomized clinical trials and prospective observational studies,” they write, “guidelines for milk or equivalent dairy products should (1) designate a broader acceptable range of intake, such as 0 to 2 or 3 cups per day, instead of a universal minimum requirement; (2) avoid recommending reduced-fat over whole milk; and (3) focus on limiting consumption of sugar-sweetened milk.”
The commentary appeared in the July 1 issue of JAMA Pediatrics, but is, unfortunately, behind a paywall.