B-vitamin boost in fight against mental decline

Thanks to the ageing baby-boom generation, elderly people are set to make up a quarter of the total European population by 2020. The most dramatic demographic changes are in the oldest age group (80 years and over) that is estimated to grow from 21.4 million in 2000 to 35 million in 2025.

Given the rising costs of healthcare, dietary measures may be a cheap and effective way of warding off health conditions that typically affect the elderly, such as Alzheimer's and heart disease.

Earlier research has indicated that higher levels of homocysteine, a amino acid known to be a marker of cardiovascular disease risk, are linked to lower cognitive test scores. Since taking folate supplements has been shown to help reduce homocysteine levels, the researchers hypothesized that this might be the reason behind folate's beneficial effects.

The study, published in the American Journal of Clinical Nutrition​, involved 321 men from the Veterans Affairs Normative Aging Study, aged between 50 and 85 years. Their cognitive function was assessed through a Mini-Mental State Examination and on the basis of measures of memory, verbal fluency, and constructional praxis at the start of the study and after three years.

Their diets were also assessed at baseline using a food frequency questionnaire, and blood samples were taken to assess serum homocysteine and B vitamins levels.

At the end of the follow-up period, the researchers, led by Katherine Tucker, PhD, of Tufts University's Friedman School of Nutrition Science and Policy, saw that there was a significant association between decline in spatial copying ability (a measure of constructional praxis) and plasma levels of homocysteine, folate, and vitamins B-6 and B-12, as well as dietary intake of each of the vitamins.

Interestingly, however, the effects of folate on cognitive function were seen to be independent of its impact on homocysteine: dietary folate seemed to protect against a decline in verbal fluency and a decline in spatial copying, whereas high homocysteine concentration appeared to be linked to recall memory decline.

"Low B vitamin and high homocysteine concentrations predict cognitive decline,"​ concluded Tucker and her team. They also said that spatial copying measures appeared to be most sensitive to these effects in the men.

Tucker added that the new study is important since it looks at the effects of the nutrients over time, rather than just at one given moment. This, she said, is an important step forward in establishing causality.

The research comes on the back of a three-year Dutch study presented at an Alzheimer's prevention conference in June, which determined that high dose folic acid supplements could slow mental decline in the elderly.

A trial sponsored by the US National Institutes of Health is currently underway to test whether very high doses of folic acid and vitamins B6 and B12 can slow the rate of mental decline in people with Alzheimer's. It is expected to be completed in February.