Folate and B12 may work in tandem to preserve cognitive function

Folate and vitamin B12, two important nutrients for the development of healthy nerves and blood cells, may work as a team to protect cognitive function among seniors, according to new research done at Tufts.

“We found a strong relationship between high folate status and good cognitive function among people 60 and older who also had adequate levels of vitamin B12,” said Martha Savaria Morris, an epidemiologist at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts. The study, which was published in the January issue of the American Journal of Clinical Nutrition, also found that low levels of vitamin B12 were associated with increased cognitive impairment.

Using data collected from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2002, Morris and her colleagues found that people with normal vitamin B12 status and high serum folate, which is a measure of folate in the blood, scored higher on a cognitive function test. Blood tests were used to determine folate and vitamin B12 levels, and the cognitive function test assessed aptitudes such as response speed, sustained attention, visual spatial skills, associative learning and memory. Cognitive impairment was identified when a subject fell into the bottom 20th percentile of the distribution on the test.

“People with normal vitamin B12 status performed better if their serum folate was high,” said Morris, the corresponding author on the study. “But for people with low vitamin B12 status, high serum folate was associated with poor performance on the cognitive test.”

Seniors with low vitamin B12 status and high serum folate were also significantly more likely to have anemia. “For seniors, low vitamin B12 status and high serum folate was the worst combination,” Morris said, noting that anemia and cognitive impairment were observed nearly five times as often for people with this combination than among people with normal vitamin B12 and normal folate.

Vitamin B12 deficiency, which affects many seniors due to age-related decreases in absorption, can impact the production of DNA needed for new cells, as well as neurological function.

Vitamin B12 is found in meat, fish, poultry, eggs and dairy products, while folate is found in leafy green vegetables, citrus fruits and beans. In 1998, the U.S. Food and Drug Administration required that all enriched cereal-grain products be fortified with folic acid, the synthetic form of folate, to help prevent birth defects in infants.

Senior study author Jacob Selhub, director of the Vitamin Metabolism Laboratory at the HNRCA and a professor at the Friedman School, said, “Our findings support the often-expressed idea that many seniors would benefit from more folate, but the research shows that we must look at the effects this would have on seniors with age-related vitamin B12 deficiency, who may be more numerous than once realized. There are also indications that too much folic acid and too little B12 is a general phenomenon that affects other systems in the body, and might be a factor in some other diseases.”