Folic acid & vitamin B12 may not improve cognitive performance, says 2-year study

By Annie Harrison-Dunn

- Last updated on GMT

Vitamin B and folic acid supplementation reduced homocysteine levels, but did not impact thinking and memory test scores, according to researchers
Vitamin B and folic acid supplementation reduced homocysteine levels, but did not impact thinking and memory test scores, according to researchers

Related tags Vitamin b12 Folic acid B vitamins

Vitamin B9 (folic acid) and vitamin B12 (cobalamin) do not benefit thinking and memory in elderly people despite lowering levels of an Alzheimer's-linked protein, according to the largest study of its kind.

The study, published in the the American Academy of Neurology’s journal Neurology​, looked at the impact of daily supplementation on 2,919 people with an average age of 74.1 and elevated blood levels of homocysteine – an amino acid which has been linked to memory loss and Alzheimer’s disease.

The participants took either 400 μg (micrograms) of folic acid and 500 μg of vitamin B12 – both tablets also containing 15 µg vitamin D3​ – or a placebo every day for two years.

The researchers from Wageningen University, Erasmus University, VU University and Radboud University, then assessed cognitive functioning by using a mini-mental state examination and tests of episodic memory, attention and working memory, information processing speed and executive function at the beginning and end of the study.

They found homocysteine concentrations decreased by 5.0 µmol/L in the B-vitamin group and 1.3 µmol/L in the placebo group. However, cognitive test scores did not differ over time between the two groups across the four cognitive areas.

The researchers said: “It may slightly slow the rate of decline of global cognition, but the reported small difference may be attributable to chance.

Disappointed hopes 

One of the study’s authors, Dr Rosalie Dhonukshe-Rutten, said: “Since homocysteine levels can be lowered with folic acid and vitamin B12 supplements, the hope has been that taking these vitamins could also reduce the risk of memory loss and Alzheimer’s disease.

vitamin B12

“While the homocysteine levels decreased by more in the group taking the B vitamins than in the group taking the placebo, unfortunately there was no difference between the two groups in the scores on the thinking and memory tests.”

The research was supported by various Netherlands organisations including the Netherlands Organization for Health Research and Development, the Dutch Dairy Association, MCO [managed care organisation] Health, Netherlands Consortium Healthy Ageing, the Dutch Ministry of Economic Affairs, Agriculture and Innovation and the respective author universities.

EFSA backed 

Vitamin B12 holds approved European Union health claims​ for its contribution to “normal homocysteine metabolism”.

Other vitamin B approvals include:

• Contributes to normal functioning of the nervous system (B1, B2, B3, B6, B12)

• Contributes to normal mental/psychological function (B1, B3, B5, B6, B9, B12)

• Contributes to the reduction of tiredness and fatigue (B2, B3, B5, B6, B9, B12)

Source: Neurology

Published online ahead of print,  doi: 10.1212/WNL.0000000000001050

Results of 2-year vitamin B treatment on cognitive performance: Secondary data from an RCT"

Authors:N. L. van der Zwaluw, R. A.M. Dhonukshe-Rutten, J. P. van Wijngaarden, E. M. Brouwer-Brolsma, O. van de Rest, P. H. In 't Veld, A. W. Enneman, S. C. van Dijk, A. C. Ham, K. M.A. Swart, N. van der Velde, N. M. van Schoor, T. J.M. van der Cammen, A. G. Uitterlinden, P. Lips, R. P.C. Kessels and L. C.P.G.M. de Groot 

Related news

Show more

Related products

show more

Related suppliers

1 comment

Flawed Study

Posted by Karl Bralich,

I was concerned because of the use of Folic Acid and not specifying the type of B-12 used.

This is a concern because recent genetics data has demonstrated that 40% of the population has polymorphisms of the MTHFR Gene which retard the conversion of Folic Acid into the active form of the vitamin by between 30% to 70 % depending on whether the variation is +/- or +/+. This directly affects homocysteine levels and at least for +/+ people, folic acid can even make things worse. The study should have used 5-methyl folate instead of folic acid.

Something similar is true for B-12 as people with polymorphisms on the MTR, MTRR and other genes can have their B-12 seriously depleted. These people need the Methylcobalamin form of B-12 so if they used the more common Cyanocobalamin form of B-12, their study is flawed. Also, the dosage they used was inadequate as evidenced by this study from PubMed which says that 500 mcg/d failed to correct Vitamin B12 deficiency in the elderly:

In fact, the study should really have done genetics on the subjects so they could determine how any genetic polymorphisms might influence the mechanisms of the increased homocysteine and inadequacy of the methylation cycle which may contribute to dementia

Report abuse

Follow us


View more