PROVO, UTAH — A recent study found people who drink low-fat milk may experience up to several years less biological aging than people who drink high-fat milk.

Larry Tucker, professor of exercise science at Brigham Young University, examined the relationship between telomere length and milk consumption in more than 5,800 U.S. adults. Telomeres are the endcaps of human chromosomes. They act as a kind of biological clock, reducing in length slightly each time a cell replicates. The older a person is, the shorter their telomeres will be.

The study, published in Oxidative Medicine and Cellular Longevity, found a strong correlation between high-fat milk consumption and increased aging. For every 1% increase in milk fat consumed (2% milk vs. 1% milk), telomeres were 69 base pairs shorter, which translates to approximately four additional years of biological aging. That number nearly doubled when researchers compared whole milk drinkers to non-fat milk drinkers.

“It was surprising how strong the difference was,” Mr. Tucker said.

The study also found that people who drank no milk aged quicker than adults who consumed low-fat milk. While more research is needed, this may suggest drinking low or non-fat milk slows down biological aging, while abstaining from milk or drinking high-fat milk accelerates the process.

“Milk is probably the most controversial food in our country,” Mr. Tucker said. “If someone asked me to put together a presentation on the value of drinking milk, I could put together a 1-hour presentation that would knock your socks off. You’d think, ‘Whoa, everybody should be drinking more milk.’ If someone said do the opposite, I could also do that. At the very least, the findings of this study are definitely worth pondering.”

Mr. Tucker added that the study supports the current Dietary Guidelines for Americans, which encourage adults to consume low-fat milk, both nonfat and 1%, and not high-fat milk, as part of a healthy diet.

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