In the news: Interaction between Omega-3s & B-Vitamins in Brain Health

Age-Related Brain Shrinkage or Atrophy

With age our brains tend to shrink in size – a normal process that scientists refer to as age-related brain atrophy. Brain volume becomes smaller, with a loss of nerve cells and the connections between them.

The rate at which the brain shrinks is often higher in those who suffer cognitive or mental decline. This accelerated rate of brain atrophy is characteristic of people with mild cognitive impairment (MCI) who go on to develop Alzheimer’s disease. About 16% of people over 70 years of age have MCI, and roughly half of them will develop Alzheimer’s.

Omega-3s, B-Vitamins & Cognition

The results of some studies suggest that the omega-3 fatty acids may help preserve brain volume and cognition [see Nov, 2014 issue of Staying Healthy]. But so far the evidence is mixed, with some studies suggesting benefit for those with MCI or early/mild Alzheimer’s, and others finding none. The same can be said of the evidence overall for the B vitamins: intervention studies with B vitamins have yielded both disappointing and promising results in these patients.

One study with encouraging findings, the 2-year long VITACOG trial, found that high dose B vitamin (folic acid, B6 and B12) supplementation significantly slowed the increased rate of brain atrophy in older individuals with MCI, compared to treatment with placebo (1).

The VITACOG trial, published in 2010, also found that the participants’ response to the B vitamin supplement was related to their blood levels of homocysteine at the study’s start. High levels of the naturally occurring amino acid homocysteine is a risk factor for brain atrophy, MCI and dementia, and the B-vitamins can lower blood concentrations of homocysteine.

Omega-3s & the B-Vitamins: Better Together?

Researchers with the Oxford Project to Investigate Memory and Ageing (OPTIMA) at Oxford University recently took another look at data from the VITACOG trial. Their findings suggest that the ability of the B vitamins to slow down brain shrinkage may depend on having an adequate supply of EPA and DHA.

The analyses of data from VITACOG showed that participants with the highest blood levels of the omega-3s at the study’s start (and assigned to the B vitamin group) had a significantly slower rate of atrophy – about 40% slower compared to those getting placebo (2).

In contrast, the B vitamin treatment had no significant effect on the rate of atrophy among participants with low initial blood levels of omega-3s. Having higher baseline omega-3 levels did not slow the rate of atrophy in placebo-takers.

According to the authors, the effect of B vitamins on brain atrophy rates seems to depend on pre-existing omega-3 blood concentrations. And this might help explain why some B vitamin trials on brain function have not produced favorable results.

The findings – which need to be confirmed – also suggest that elevated homocysteine levels (which are lowered by B vitamins) also determine the effects of omega-3s in MCI and dementia, and may explain why some omega-3 trials have failed.

An editorial (3) accompanying this study points out that the omega-3s are thought to be protective by reducing free radical production and by stimulating the growth of axons and dendrites that project from, and connect nerve cells to one another. It appears that having sufficient levels of B vitamins and low homocysteine are required for the brain to optimally distribute and use the omega-3s.

References

1. Smith AD, et al. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. Plos One 5:e1224, 2010.
2. Jerneren F, et al. Brain atrophy in cognitively impaired elderly: the importance of long-chain ω-3 fatty acids and B vitamin status in a randomized controlled trial. Am J Clin Nutr 102: 215-21, 2015.
3. Blasko I. Editorial. Interaction of ω-3 fatty acids with B vitamins in slowing the progression of brain atrophy: identifying the elderly at risk. Am J Clin Nutr 102:7-8, 2015.