Seniors who ate healthful diets scored better on tests of mental acuity than did their peers who consumed junk food, according to a new study.
We've long heard that foods rich in omega-3 fatty acids and vitamins B, C, D and E were "brain food." And studies have consistently shown that those with a diet high in these nutrients maintained better cognitive function in old age. But the new research not only reaffirms the association, it uses a novel and more reliable approach: the investigators determined study participants' diets by collecting blood samples and analyzing them for 30 biomarkers of diet, rather than using notoriously imprecise self-reported food surveys.
"The combination of the B vitamins, the antioxidants C and E, plus vitamin D was the most favorable combination of nutrients in the blood for healthy brain aging in our population," study author Gene L. Bowman, an assistant professor of neurology at the Layton Aging & Alzheimer's Disease Center, Oregon Health & Science University, told WebMD.
Bowman and colleagues evaluated 104 men and women, average age 87, to determine several measures of brain health in old age: they asked participants to take tests of memory and thinking skills, and had a subset of 42 participants undergo MRIs to determine actual brain volume -- a measure of cognitive health. (For example, Alzheimer's disease patients experience more pronounced brain shrinkage than their healthy peers).
They then matched cognitive abilities to the blood samples and found that those who tested high for memory and critical thinking -- and had less brain shrinkage -- were more likely to have biomarkers of healthful compounds in their blood. What’s more, people who tested poorly were more likely to have biomarkers for trans-fats, an unhealthy fat source found in junk foods, like packaged baked goods and fast food meals.
While the study demonstrates a link between healthful eating and cognitive ability, it's important to note that age and education level (a common measure used to determine cultural factors like socioeconomic status and health care access) were stronger predictors of brain health than was diet. While age explained 46 percent of the variation in brain function, diet only explained 17 percent. That's still a significant role and the association between diet and brain volume was stronger, with diet explaining 37 percent of shrinkage variance. Researchers hope that the association they found will be impetus enough for many people to modify their diets.
"These findings are based on average people eating average American diets," co-author Maret Traber, a principal investigator at the Linus Pauling Institute told the AFP. "If anyone right now is considering a New Year's resolution to improve their diet, this would certainly give them another reason to eat more fruits and vegetables."
The study didn't specify food sources, as nutrients were determined from blood sample analysis, though fruits and vegetables are the most common source of vitamin C. Omega-3 fatty acids and vitamin D are both found in fatty fish, like salmon. Nuts and seeds are best for vitamin E and B vitamins are found in whole grains and dairy.
The study was published in Neurology, the journal of the American Academy of Neurology.