If you give your youngsters reduced-fat or skim milk, you may want to consider switching them to whole. A new study published in the American Journal of Clinical Nutrition finds that kids who drink whole-fat milk are significantly leaner and have higher vitamin D levels than those who consume 2 percent, 1 percent, skim, or no milk.
To reach these conclusions, pediatricians at St. Michael’s Hospital in Toronto analyzed data from 2,700 kids ages two to six. The whole-milk drinkers had an average BMI of 0.72 points lower than the children given reduced-fat milk.
Since kids grow like sprouts and naturally have more body fat than adults, BMI is calculated differently for them, taking into account their age and sex. Therefore, for children, a one-point differential is actually the difference between being healthy and overweight or overweight and obese, says lead study author Dr. Jonathon Maguire. In other words, 0.72 points is a big deal.
“An easy way to understand this is the kids who drank whole milk had threefold decreased odds of being overweight compared to the rest,” Maguire says.
Although this study didn’t dig into why the whole milk drinkers were leaner, Maguire has a theory. Unlike adults who have open access to foods and beverages and often eat more than we really need, kids get only what their parents give them and generally stop putting stuff in their mouths when they’re full. Since whole-fat milk is more filling than low- and nonfat milks, Maguire thinks kids who drink whole milk probably consume fewer food calories. “Children served reduced-fat milk may be eating more calorically dense, fattier foods to make up for the calories they’re not getting from milk,” he explains.
This would explain why, in this study, total volume of milk consumed didn’t make any difference in terms of BMI. “Kids regulate intake based on fullness,” Maguire says. “They’re not going to keep on drinking whole milk until they are obese.” So if a child does drink a lot of whole milk, it’s likely in place of other calories, making any perceived negatives about the beverage, namely its high calorie and fat content, basically moot.
Then there's the vitamin D differences. All cow’s milk in the U.S. must be fortified with vitamin D, so any type should deliver the same amount of the nutrient. And yet, the kids who consumed one cup of whole milk each day had comparable vitamin D levels to those who consumed three cups of 1 percent. According to Maguire, the children given reduced-fat milk were twice as likely to have a vitamin D deficiency as those served whole milk.
This may be because vitamin D is a fat-soluble hormone. “Vitamin D is carried into the body with fat, so perhaps milk with more fat delivers more vitamin D,” Maguire says. “Whole-fat milk is likely better at increasing vitamin D levels in kids.”
These findings fly in the face of the latest federal nutrition guidelines and the American Heart Association’s dietary recommendations, both of which still suggest reduced-fat dairy for children. But given all the emerging evidence showing full-fat dairy doesn’t make people fatter or any less healthy — and may, in fact, be beneficial — the tide could very well shift in the near future.