Fish oil, and other sources of heart-healthy omega-3 fatty acids, have been found to boost the effectiveness of B-vitamin supplements in combating age-related cognitive declines.

That’s the upshot of new research by the University of Oxford that shows the two natural sources of brain-boosting agents amount to a one-two punch against s mental declines in older people with memory problems.

The findings, published in published in the Journal of Alzheimer's Disease, are based on a study involving more than 250 people with mild cognitive impairment (MCI— a precursor to Alzheimer’s disease in which brain function is below what is normally expected for a person's age but is not significant enough to interfere with daily life.

Study participants were given tests to measure their cognition and memories and blood tests of two omega-3 fatty acids commonly found in oily fish: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

The participants were split into two groups, one of which received a B-vitamin supplement and the other an inactive placebo pill over two years.

At the end of the study the researchers found those receiving B vitamins and omega-3 acids scored better on cognitive and memory tests.

“We found that for people with low levels of omega-3, the vitamin supplements had little to no effect. But for those with high baseline omega-3 levels, the B vitamins were very effective in preventing cognitive decline compared to the placebo,” said researcher Dr. Abderrahim Oulhaj.

“This result complements our previous finding that B vitamins slow the rate of brain atrophy in MCI only in those with a good omega-3 level to start with.”

Co-researcher David Smith said they team now plans to study whether the combination of supplements can prevent dementia in people with mild memory loss.

“The next stage will be to see whether providing a combination of B vitamins and omega-3 supplements can slow the conversion from MCI to Alzheimer's disease,” he said. “This would be an important step in the prevention of Alzheimer's disease. We have high hopes that this trial would work but funding is not easy to obtain for such studies.”