WASHINGTON - Elderly people with higher levels of certain vitamins and omega 3 fatty acids in their blood score better on mental acuity tests than those who eat junk food, a study released Wednesday showed.
The study published in Neurology, the journal of the American Academy of Neurology, also showed that eating better could help reduce the brain shrinkage commonly associated with Alzheimer's disease.
"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 at the Linus Pauling Institute and study co-author.
Researchers at the institute at Oregon State University conducted the study, one of the first of its kind, along with scientists at the Oregon Health and Science University in Portland.
The study, carried out among 104 people at an average age of 87, specifically measured a wide range of blood nutrient levels instead of basing results on food questionnaires, which are less precise and less reliable.
"The vitamins and nutrients you get from eating a wide range of fruits, vegetables and fish can be measured in blood biomarkers," Traber said.
"I'm a firm believer these nutrients have strong potential to protect your brain and make it work better."
Researchers noted the positive effects of high levels of vitamins B, C, D and E, as well as the healthy oils most commonly found in fish, on mental quickness and brain size.
Those with a higher intake of trans-fats - commonly found in fried foods, fast foods and other less healthy diet options - did not perform as well on cognitive tests.
Researchers found that while age and education affected performance on the cognitive tests, nutrient status accounted for 17 per cent of the variation in scores, and 37 per cent of the differences in brain volume.
Of those who took part in the study, seven per cent showed a vitamin B12 deficiency, and 25 per cent did not have enough vitamin D in their systems.
Scientists tested 30 different nutrient biomarkers. In addition, 42 participants had MRI scans to measure their brain volume.
"These findings are based on average people eating average American diets," Traber said.
"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."
Study co-author Gene Bowman of the Oregon Health and Science University added while results needed to be confirmed, "it is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet."