Nutrients combine to make unique “signature patterns” or profiles in the blood, and researchers in one study tested which profiles were linked to better cognitive health. Doctors measured nutrient levels in 104 adults without dementia, aged 77 to 97, and found that, compared to those with lower levels, those with the highest blood levels of folate, vitamins B1, B2, B6, B12, C, D, and E, and omega-3 fatty acids scored highest on mental tests and had healthier MRI brain scans.

The brain can shrink with age, raising chances for dementia and Alzheimer’s disease. Those in the study with the highest levels of trans fats—partially hydrogenated oils common in highly processed and deep fried foods—scored lowest on mental tests and had signs of brain shrinkage.

Doctors said we already knew trans fats raise bad cholesterol and lower good cholesterol levels, and are bad for the heart, but this is the first study to link trans fats and brain health. “It is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet,” researchers concluded.

Reference: Neurology; 2012 Jan 24; Vol. 78, No. 4.