A sufficient supply with vitamin E and folate seems to be key for cognitive health

A new review concludes that the strongest evidence for preventing cognitive decline and/or improving cognitive function is related to increased intakes of vitamin E and folate among individuals with low status of these vitamins.

The review analyzed the results of observational studies and randomized controlled trials that investigated intakes or blood concentrations of vitamin E, folate or vitamin B12 in relation to cognitive change over time (1). The data analysis indicated that elderly adults consuming less than approximately six to seven mg vitamin E per day (less than half of the recommended intake of 15 mg/day) are most likely to experience a benefit for cognitive health from an increased vitamin E intake, either through food or supplementation. Adults with blood folate levels below 12 nmol/L and/or total homocysteine levels above 11.3 μmol/L and/or people with intakes of less than 350 μg folate per day may expect improved brain functions due to increased folate intakes. The literature on the relation between vitamin B12 and cognition is not as clear: studies do not consistently include populations consuming less than 2.4 μg vitamin B12 per day and occasionally rely only on serum B12 levels to assess status, which is a poor indicator of marginal deficiency.

The researchers noted that ideally randomized controlled trials should be designed to target people with an insufficient vitamin status, and changes of parameters of cognitive functions should be based on measurement of levels of serum markers or intakes before, during and after the intervention. A likely explanation for null findings in randomized controlled trials testing effects of nutritional supplements, is that the nutrient status of participants was already at a protective level, and further supplementation conferred no additional benefit. Although most countries have well-established recommended dietary intake levels to avoid frank nutritional deficiency in most of the population, the scientists said that these recommendations do not address the vitamin levels required to maintain brain health and to support optimal cognitive function in aging populations.

1. Barnes J. L. et al. Consideration of nutrient levels in studies of cognitive decline. Nutrition Reviews. Published online October 2014