Researchers with funding from the USDA's Agricultural Research Service are calling for studies examining the implications of having high folate status due to fortification and too little vitamin B12 due to aging.
As part of a recent study, the scientists linked high folate and a low vitamin B12 intake to a negative effect on mental agility in seniors.
B vitamins are involved in the synthesis of chemicals crucial to brain function, while many US cereal products have been fortified with folic acid since 1998, the effects of which some scientist say are not all known.
"The people with high folate and low B12 status were more likely to exhibit both cognitive impairment and anemia than those with normal folate and low B12 status," said epidemiologist Paul Jacques.
Published in the current issue of the US Department of Agriculture's Agricultural Research Magazine, the study was carried out at the ARS' Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) in Boston by Jacques and led by Martha Morris.
Based on the analysis of data collected from the US population for the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2002, the researchers drew on blood tests to determine the volunteers' folate and vitamin B12 levels. They then used a combination of blood markers to classify subjects' vitamin B12 ranking.
The researchers found that among those people aged 60 and older, those with a high blood level of folate and an adequate level of vitamin B12 scored high on cognitive function tests.
The participants were tested on their speed of response, as well as their attentiveness, visual-spatial skills, associative learning and memory.
Low vitamin B12 levels are common among older people due to their poorer gastrointestinal conditions and the effect on absorption. Accordingly, the researchers found that those people who had low vitamin B12 blood levels also had lower scores on cognitive tests.
Scientists have long known that being seriously deficient in vitamin B12 leads to impaired cognitive function due to neurological complications. But the researchers this time say they found an interesting association among seniors aged 60 and older whose vitamin B12 blood levels were low. Aging and taking stomach-acid blockers can contribute to a gradual lessening of B12 absorption in the body.
The researchers recommend future studies that look into the implications of having too much folic acid, due to fortification, and too little vitamin B12, due to poor absorption.
"Nutrition and Brain Function: Boosting Our Knowledge of Brain Food." Agricultural Research Magazine. November/December 2007 - Vol. 55, No. 10.