, new research suggests.
The study provides important “pieces of the puzzle” of the diet and cognition connection, but the results aren’t “ready for prime time,” study investigator Roger S. McIntyre, MD, professor of psychiatry and pharmacology, University of Toronto, said in an interview.
“I don’t think we’re there yet when it comes to recommending supplementation to the general public,” said Dr. McIntyre, adding a larger “more compelling study” is needed.
The study was published online Jan. 14 in The American Journal of Geriatric Psychiatry.
Clinically meaningful?
Research shows that 25%-50% of community-dwelling adults aged 65-85 years have some cognitive impairment. Other evidence indicates cognition is affected by dietary fat intake.
Many lines of research show that alterations in lipid homeostasis can cause brain dysfunction, said Dr. McIntyre. “This shouldn’t surprise us because our brain is made up of protein, water, and fat.”
This new analysis used combined data from the 2011-2012 and 2013-2014 cycles of the National Health and Nutrition Examination Survey (NHANES), a series of ongoing cross-sectional surveys conducted by the Centers for Disease Control and Prevention. The data are collected in two phases, an in-home face-to-face interview and a physical examination.
Researchers obtained dietary intake information through two 24-hour dietary recall interviews. Dietary information included total energy (kcal/d), intakes in grams per day (g/d) of total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), PUFA, total omega-3 and total omega-6 fatty acids, and milligrams per day (mg/d) of cholesterol.
For cognitive function, the researchers used total and delayed recall scores of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), the animal fluency test, and the digit symbol substitution test (DSST).
The study included 2,253 adults aged 60 years and older (mean age, 69.4 years) and 51% were non-Hispanic White individuals.
After adjustment for age, sex, race/ethnicity, educational attainment, smoking status, alcohol consumption, income, and total energy, dietary intake of PUFA and omega-6 fatty acid was positively associated with DSST.
The DSST score increased about 0.06 standard deviation (SD) (about 1 score) with each SD increase in these fatty acids (8.8 g/d for PUFA and 7.9 g/d for omega-6) (P values were .02 for PUFA and .01 for omega-6).
However, it’s unclear what an improvement of 1 DSST score means clinically, said Dr. McIntyre. “The P value is significant, but how does that translate? Does this mean a person can now think more clearly or function better?”