Drinking cow’s milk is a great way to add protein to your diet and build strong teeth and bones. It has also been linked with a reduced risk of heart disease and stroke and lower rates of obesity. However, experts are divided on whether low-fat milk or whole milk is healthier. Now, according to the latest research — drinking low-fat milk is associated with a longer life span.
THE SCIENCE
Larry Tucker, PhD, a professor of exercise sciences at Brigham Young University tracked 5,834 adults to determine whether milk consumption was associated with telomere length, a sign of biological aging.
The research, published in the journal Oxidative Medicine and Cellular Longevity, found those who drank low-fat milk had longer telomeres (and less biological aging) than those who drank high-fat milk, including 2% and whole milk. Tucker equates the difference to an additional four-and-a-half years of cellular aging.
WHY LOW-FAT MILK MIGHT DECREASE BIOLOGICAL AGING
According to Tucker, a significant difference in the amount of saturated fat between low-fat and high-fat milk could be the reason for the decrease in biological aging. In whole milk, 50% of the calories are from fat compared to 21% for 1% milk (and between 0 and 2% in skim milk).
“High-fat dairy is higher in fat than people realize,” he says. “Unlike other foods that calculate fat based on percentage of calories, milk fat is calculated by the percent of milk’s weight.”
Diets that are high in fat — especially saturated fat — are associated with increased risk of cardiovascular disease, chronic inflammation, negative changes to gut bacteria, lower breast cancer survival rates and even neurological changes in the brain. Based on such findings, the U.S. Dietary Guidelines recommend choosing fat-free or low-fat dairy products, including milk, yogurt and cheese.
WHY WHOLE MILK CAN STILL BE HEALTHY
“Recommendations to lower saturated-fat consumption have been primarily based on studies showing that higher intakes of saturated fat present in whole-fat dairy products raise LDL or ‘bad’ cholesterol levels, which could raise risk of heart disease,” explains study co-author Marcia de Oliveira Otto, PhD, assistant professor at UTHealth School of Public Health. However, “an increasing number of large studies examining the link between saturated fats present in dairy foods and heart disease do not support that hypothesis.”
In particular, Otto cites heptadecanoic fatty acid (a saturated fatty acid in milk fat), which could reduce the fragility of brain arteries and lower the risk of dying from a stroke. In one study, adults with higher levels of heptadecanoic fatty acid in their blood were 42% less likely to die from stroke.
Moreover, other research supports the benefits of consuming whole milk and other high-fat dairy products: Higher intake of whole milk and full-fat yogurt was associated with a lower risk of cardiovascular events and total mortality, according to research published in The Lancet.
THE BOTTOM LINE
“An important take-home message from our study is making judgments about whether foods are healthy solely based on fat content leads to confusion and misinformation,” says de Oliveira Otto. “Since dairy foods are important sources of essential nutrients, reducing dairy consumption may not necessarily lead to better health.”
If you have heart disease or are at risk for it, it might be a good idea to opt for skim and low-fat dairy. Otherwise, healthy adults can continue to include full-fat dairy as part of a well-balanced diet.
