Older women are likely to have larger brains if their blood contains high quantities of omega-3 fatty acids, a study from the US has found.
The researchers, based at the University of South Dakota in Sioux Fall, also found that the hippocampus - the part of the brain which stores memories - was found to have greater capacity.
The benefits of Omega-3 have been well documented. Found in foods such as oily fish, the acids help the nervous system to develop and been linked to lower levels of dementia for some time.
A total of 1,111 post-menopausal women took part in the study, with none having dementia at the start. They each provided blood samples so that the team could measure levels of two types of omega-3 fatty acids - eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Eight years later, scans were taken to assess the size of their brains and those with the highest levels of omega-3 were found to have the greatest capacity on average.
Dr Laura Phipps from the charity Alzheimer's Research UK said that evidence on omega-3's benefits has previously been mixed, but this study the acids can have an impact on brain size.
However, she believes further studies need to be made before anything conclusive can be stated.
"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," she said.
"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."
Dr Phipps added that current research suggests the best way of minimising the risk of cognitive conditions is by consuming a balanced diet, keeping blood pressure and cholesterol under control and getting regular exercise.
The study was published in the Neurology journal on January 22nd.
Read more about Barchester's dementia care homes.