A new study challenges claims from some international scientific circles, that having high blood levels of folate (folic acid) increases the risk of poor cognition in older adults, especially in those with low levels of vitamin B12. On the contrary the study found that having higher folate seemed to be associated with better cognitive function in these older adults.

The study published today (Monday, 15th June 2020) in the British Journal of Nutrition, forms part of the largest representative study of its kind conducted among older persons.

Both vitamin B12 and folate are essential vitamins for the nervous system and healthy blood cells. Deficiency of folate in early pregnancy can lead to neural tube defects (NTDs) in new-born babies. This is the reason for mandatory fortification of the food supply with folic acid in the US and other countries (but not Ireland or Europe). While fortification is proven to reduce NTDs, several influential publications in the US suggest that very high folate levels in older persons, if coupled with low vitamin B12, leads to poorer brain function and a faster rate of cognitive decline. Largely because of such fears, no country in Europe has implemented mandatory folic acid fortification, although the NTD rates have not declined in two decades and may be rising in Ireland, according to recent data.

What has the new research unveiled?

Using blood samples from over 3,700 Irish older adults aged 50 and over, the study compared cognitive health in individuals grouped by their combinations of vitamin B12 and folate blood levels. It found no evidence that having high blood levels of folate affected the risk of cognitive decline in those with low levels of vitamin B12. Moreover, having higher folate seemed to be associated with better cognitive function in these older adults.

Key findings:

• Cognitive performance was not worse in older people with low vitamin B12 combined with high folate (representing 1.5% of older adults in Ireland)
• Those with normal vitamin B12 levels and high folate levels (7.6% of older adults) performed better cognitively than the others
• The use of folic acid — containing supplements was uncommon, with higher rates among women than men but less than 4% overall taking supplements

Why do the findings matter?

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