Posted on Mon, 4 Dec 17
Drinking cow’s milk could be a risk factor for cognitive decline later in life, with some people more genetically susceptible than others.
Cow’s milk is a source of the sugar lactose, which in people who have a persistent lactase gene can be metabolised to D-glactose. Because D-galactose generates oxidative stress and increases cognitive aging in experimental studies, a team of researchers decided to see if people who drink cow’s milk might be at increased risk cognitive decline later in life.
To test their hunch, they looked at dietary records of people in midlife then their neurocognitive evaluation results across a 20-year period into later life. They also considered whether they were lactase persistent by noting if they had one of two single nucleotide polymorphisms in genes that code for lactase (LCT-13910 C/T or LCT-14010 G/C).
Results revealed that milk intake greater than 1 glass a day was indeed associated with a greater rate of cognitive decline from midlife to late-life.
But in contrast to their theory that D-galactose could play a causative role, they found a significantly higher rate of cognitive decline in those without a persistent lactase gene – the opposite to what they expected.
“Our results suggest that greater milk intake at midlife may be associated with greater rate of cognitive decline over a 20-year period,” noted the investigators. “These results are consistent with results from a recent study of 3076 participants 65.5 years of age at the time of neurocognitive evaluation, in which milk consumption was associated negatively with verbal and working memory performance.”
“Other potential mechanisms through which milk intake may affect the rate cognitive decline should be explored,” they commented.
Petruski-Ivleva N, Kucharska-Newton A, Palta P, et al. Milk Intake at Midlife and Cognitive Decline over 20 Years. The Atherosclerosis Risk in Communities (ARIC) Study. Nutrients. 2017 Oct 17;9(10).