In a new study, published in The American Journal of Clinical Nutrition, researchers have revealed that children who drank whole milk had 40% lower odds of being overweight or obese compared with children who consumed reduced-fat milk.
A systematic review and meta-analysis led by St. Michael's Hospital of Unity Health Toronto explored the relationship between children drinking cow milk and the risk of being overweight or obese by analyzing 28 studies from seven countries.
Study challenges international guidelines
The researchers said that none of the studies, including data of almost 21,000 children between the ages of one and 18 years old, showed that the kids who drank reduced-fat milk had a lower risk of being overweight or obese. Out of the 28 studies, 18 suggested that children who drank whole milk were less likely to be overweight or obese.
The study findings have challenged the Canadian and international guidelines that recommend children to consume reduced-fat cow milk instead of whole milk starting at age two to reduce the risk of obesity.
Randomized controlled trial
Dr. Jonathon Maguire, lead author of the review and a pediatrician at St. Michael's Hospital, said: "The majority of children in Canada and the United States consume cow's milk on a daily basis and it is a major contributor of dietary fat for many children. In our review, children following the current recommendation of switching to reduced-fat milk at age two were not leaner than those consuming whole milk."
Dr. Maguire said that they hope to establish the cause and effect of whole milk and lower risk of obesity in a randomized controlled trial. "A randomized controlled trial would help to establish cause and effect but none were found in the literature," the researcher said.
However, all the studies examined were observational studies, meaning that there is need for more research to establish beyond confusion that whole milk caused the lower risk of overweight or obesity. "Whole milk may have been related to other factors which lowered the risk of overweight or obesity," added Dr. Maguire, who is also a scientist at the MAP Centre for Urban Health Solutions.