People who regularly consume low-fat rather than high-fat milk have younger aging biomarkers, according to new research from Brigham Young University.

Among the more than 5,800 U.S. adults studied, people who frequently drank low-fat or no-fat milk experienced about 4.5 fewer years of biological aging than participants who often consumed whole milk. The more milk participants drank, the stronger the effect, reported exercise science professor Larry Tucker, Ph.D.

“It was surprising how strong the difference was,” said Tucker. “If you’re going to drink high-fat milk, you should be aware that doing so is predictive of or related to some significant consequences.”

The differences between the two groups of milk drinkers appeared in their telomeres, a biological marker which shortens with age. Habitual whole-milk consumers had significantly shorter telomeres.

Notably, the findings weren’t true for people who had a low-fat diet, only those who regularly consumed moderate or high levels of saturated fats.

“It’s not a bad thing to drink milk,” Tucker concluded. “You should just be more aware of what type of milk you are drinking.”