Eating more oily fish can increase brain size in later life and may help prevent age-related mental decline, a study has found.
People with higher levels of omega-3 fatty acids found in fish oil preserve bigger brains as they age, the research shows. In particular, they maintain more nerve cells in the hippocampus, the brain’s key memory centre.
The larger neural volume linked to omega-3 intake is equivalent to reducing the effects of brain ageing by up to two years, say scientists.
Researchers measured levels of two essential omega-3 fatty acids, EPA and DHA, in the blood of 1,111 women taking part in the US Women’s Health Initiative Memory Study.
Eight years later, when the women had an average age of 78, magnetic resonance imaging (MRI) scans were performed to measure their brain size.
Those who started out with higher intakes of omega-3 were found to have larger total brain volumes. A doubling of omega-3 levels was associated with a 0.7 per cent increase in overall brain size.
In addition, the hippocampus area was 2.7 per cent larger in women with higher levels of the fatty acids.
Lead scientist Dr James Pottala, from the University of South Dakota in Sioux Falls, US, said: “These higher levels of fatty acids can be achieved through diet and the use of supplements, and the results suggest that the effect on brain volume is the equivalent of delaying the normal loss of brain cells that comes with ageing by one to two years.”
The findings appear in the latest edition of the online journal Neurology.
Shrinking brain volume is a known sign of Alzheimer’s disease as well as normal ageing.
Dr Laura Phipps, from Alzheimer’s Research UK, said: “This study suggests that higher levels of omega-3 fatty acids in blood are linked to larger brain size but the possible reasons for this association need further investigation.”