Researchers in the US have found that older women with higher levels of omega-3 fatty acids in their blood are also more likely to have larger brains. The size of the hippocampus – an area of the brain involved in learning and memory – was also associated with omega-3 levels in blood. The research is published on 22 January in the journal Neurology.
Omega-3 is a group of fatty acids found in high levels in oily fish. It is known to play a role in the development of the nervous system and is currently being investigated for potential benefits in a range of health conditions. While some studies have suggested that people who consume more omega-3 in their diet may have a lower risk of dementia, other studies have failed to find evidence for this.
To investigate this link further, researchers studied 1,111 postmenopausal women who were already enrolled onto a different study investigating the effects of hormone therapy on memory. At the start of the study, the women – who did not have dementia – provided blood samples to allow the team to measure levels of two omega-3 fatty acids called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in their blood. Approximately eight years after the blood was taken, the women had brain scans to look at the size and structure of the brain.
The researchers found that higher blood omega-3 levels were associated with a larger brain volume in the volunteers after eight years. This was particularly evident in an area of the brain called the hippocampus, which is involved in memory formation and known to be particularly vulnerable to damage in Alzheimer’s disease.
Dr Laura Phipps of Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“There has been mixed evidence as to the benefits of omega-3 fish oils on the brain and whether they may protect against memory decline and dementia. 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. We know that the brain gets smaller in people with dementia, but it is unclear from the study what effect larger brain size would have on memory and thinking in the volunteers or their long-term risk of developing dementia.
“The best way to assess whether omega-3 could protect against dementia is through clinical trials and so far, trials of omega-3 supplementation have not shown benefits in protecting against cognitive decline. Currently, research suggests that a balanced diet, along with regular exercise, not smoking, maintaining a healthy weight and keeping blood pressure and cholesterol in check may help to keep our brains healthy as we get older. With hundreds of thousands of people in the UK alone living with dementia, we must continue to invest in research to understand the risk factors.”