The study, published in Nutrients, evaluated the potential of dietary B vitamins to influence the long-term risk of dementia in a population of more than 1,300 French participants – finding that while intakes of vitamin B6 and vitamin B12 had no association to dementia development higher intakes of folic acid (vitamin B9) are linked to a decreased incidence of dementia.
Led by Sophie Lefèvre-Arbogast from the University of Bordeaux and INSERM, the team noted that while previous studies have suggested B vitamins may lower the risk of dementia, “epidemiological findings, mostly from countries with folic acid fortification, have remained inconsistent.”
“We found in a large cohort of older persons from France—a country with no folic acid fortification and relatively low average intake levels—a strong association between a higher intake of folate and a lower long-term risk of dementia,” the authors wrote.
“It is thus possible that folate is protective for the brain in lower intake ranges (as those observed in France) and becomes inefficient (…) at higher ranges,” said the team.
“The protective role of folate in populations with relatively low basal folate status such as France may be worth exploring in future dementia prevention trials,” they suggested.
Folic acid fortification
To date 78 countries globally have implemented mandatory fortification programmes for folic acid with the aim of preventing neural tube defects (NTDs) in babies. But despite growing calls from NGOs, health experts and researchers, many EU member states have not implemented mandatory fortification programmes.
As such many European countries have a lower intake of folic acid in the general population, the team noted – who suggested that inconseistencies between studies on folic acid in the North America and Europe may be due to lower baseline levels.
“The most evident reason may pertain to differences in baseline intakes between French and US populations, with lower intakes reported in France, a country with limited supplement use and no folic acid fortification,” said the authors – who noted that previous studies in other low-baseline European countries such as Italy, the Netherlands and the UK have suggested higher folic acid intake could be linked to dementia and memory in older people.
Lefèvre-Arbogast et al, analysed data from 1,321 participants who took part in the Three-City Study. Face-to-face interviews were performed at the start of the to identify socio-demographic, lifestyle, and health-related characteristics, in addition to neuro-psychological testing, and blood sampling.
Furthermore, the team noted that all participants completed a 24-hour dietary recall, were free of dementia at the time of diet assessment, and were followed for an average of 7.4 years.
“In Cox proportional hazards models adjusted for multiple potential confounders, including overall diet quality, higher intake of folate was inversely associated with the risk of dementia (p for trend = 0.02), with an approximately 50% lower risk for individuals in the highest compared to the lowest quintile of folate,” wrote the French researchers.
No association was found for vitamins B6 and B12, however Lefèvre-Arbogast and her colleagues noted that “vitamin B12 malabsorption has not been explored through circulating level data in this cohort of older persons and deserves further research.”
Volume 8, Issue 12, Page 761, doi:10.3390/nu8120761
“Dietary B Vitamins and a 10-Year Risk of Dementia in Older Persons”
Authors: Sophie Lefèvre-Arbogast, et al