A new study has found that people with dementia who regularly ate seafood saw less brain decline if they carried a certain gene.

The benefits of seafood for the brain have long been pushed by the scientific community, and now a study from Rush University Medical Centre in Chicago has found a link between people with Alzheimer’s who ate one to three servings of seafood a week, and a reduced amount of damage in their brain.

However, real benefits were only seen in people who carried a gene called ApoE4, which is carried by around 36 per cent of people with Alzheimer’s disease.

Researchers examined the brains of 286 people who had recently died from Alzheimer’s disease and who had provided data on their fish consumption in the years leading up to their death.

Previously, there had been concern that eating lots of seafood could be damaging for people with Alzheimer’s disease because of the high levels of mercury that can be naturally present, and which can be dangerous for the brain. However, the researchers discovered the toxic effects of mercury were reduced by selenium, which is also naturally present in seafood.

Dr Laura Phipps, from Alzheimer’s Research UK said:

‘This study links moderate seafood consumption with lower levels of Alzheimer’s-related brain changes in elderly people who carry a risk gene for the disease, but we must be careful when drawing conclusions about the wider population.

‘Current research is underway to investigate the benefits of a diet rich in omega-3 fatty acids in those at risk of memory and thinking problems, but at this time there is no evidence to suggest fish oil supplements could prevent dementia. Dementia risk is a complex mix of age, genetics and lifestyle factors.’