Diet and nutrition linked to cognitive ability, brain shrinkage

A new study shows that elderly people with higher levels of some vitamins and omega-3 fatty acids in their blood performed better on mental acuity tests with less brain shrinkage typical of Alzheimer’s disease, while “junk food” diets produced the opposite result.

Researchers from the Oregon Health and Science University and the Linus Pauling Institute at Oregon State University measured a wide range of blood nutrient levels, finding positive effects of high levels of vitamins B, C, D and E and the healthy oils most commonly found in fish. Consistently worse cognitive performance was associated with a higher intake of the type of trans-fats found in baked and fried foods, margarine, fast food and other less-healthy dietary choices.

The study, which was published in Neurology, the medical journal of the American Academy of Neurology, was conducted with 104 people, at an average age of 87, with no special risk factors for memory or mental acuity. It tested 30 different nutrient biomarkers in their blood and 42 participants also had MRI scans to measure their brain volume.

“This approach clearly shows the biological and neurological activity that’s associated with actual nutrient levels, both good and bad,” said Maret Traber, a principal investigator with the Linus Pauling Institute.

Much of the variation in mental performance depended on factors such as age or education, but nutrient status accounted for 17 percent of thinking and memory scores and 37 percent of the variation in brain size.

Cognitive changes related to different diets may be due both to impacts on brain size and cardiovascular function.

The epidemiology of Alzheimer’s disease has suggested a role for nutrition, the researchers said in their study, but previous research using conventional analysis—and looking in isolation at single nutrients or small groups—have been disappointing. The study of 30 different blood nutrient levels done in this research reflects a wider range of nutrients and adds specificity to the findings.