Drinking low-fat milk is associated with less ageing in adults, according to a new study which supports existing dietary guidelines which do not recommend high-fat milk as part of a healthy diet. The study, published in the journal Oxidative Medicine and Cellular Longevity, assessed 5,834 US adults and found that people who drink low-fat milk experience biological ageing slower by several years than those who drink high-fat (2 per cent and whole) milk.
"It was surprising how strong the difference was. 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," said Larry Tucker, study co-author from Brigham Young University (BYU) in the US.
The researchers analysed the link between the length of the end of chromosomes -- the coiled structure in which DNA is present in cell nucleus -- milk intake frequency and fat content consumed.
According to the scientists, these chromosome ends, called telomeres, act like a biological clock, and they're correlated with age.
Each time a cell replicates, they said, humans lose a tiny bit of these end caps.
Hence older people have shorter telomeres, the researchers added.
The more high-fat milk people drink, the shorter their telomeres are, according to the BYU study.
According to the study, for every one per cent increase in milk fat consumed, telomeres were 69 units shorter in the adults studied.
This translated into more than four years in additional biological ageing, the researchers said.
In the extremes of milk drinkers, adults who consumed whole milk had telomeres that were a striking 145 molecules shorter than non-fat milk drinkers.
ut together a 1-hour presentation that would knock your socks off," Tucker said.
"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," he added.
The study also found that milk abstainers had shorter telomeres than adults who consumed low-fat milk.