With no cure on the horizon, Alzheimer’s disease is perhaps the greatest fear for anyone over 60. Diet and exercise are two of the best ways for older adults to maintain their mental function, and a new study has identified one type of food that may be especially helpful in staving off the disease.

Eating seafood appears to decrease the risk of developing Alzheimer's disease, according to scientists from the Alzheimer’s Disease Center at Rush University in Chicago.

People who reported eating seafood one or more times a week had fewer plaques and neurofibrillary tangles in the brain.

Researchers used data from the Memory and Aging Project (MAP), an ongoing research project in which participants are assessed yearly and their brains autopsied upon death, and were able to compare each person’s autopsy results with their diet.

People who reported eating seafood one or more times a week had fewer plaques and neurofibrillary tangles in the brain, hallmarks of Alzheimer’s disease, compared to people who ate less or no seafood.

Fish and fish oils have been associated with better brain health and a decreased risk of Alzheimer’s disease in many studies, but the buildup of mercury from fish and its possible damage to the brain have remained concerns. This study found that despite higher levels of mercury in the brains of those who ate more fish, there was no correlation with Alzheimer’s disease or other forms of dementia.

The findings were most apparent in people who carried a faulty gene associated with an increased risk of Alzheimer’s disease.

While the type of fish or seafood considered best for protection against the disease was not determined, the researchers believe you would need to eat more than two seafood meals a week to gain the protective benefits they found.

This may be bad news for those who don’t like fish and believe that taking fish oil supplements would have the same benefits: The study did not show that was necessarily true. However, participants who took supplements did not take them regularly, making it difficult to truly understand whether or not they would be beneficial, so the jury is still out.

Alzheimer’s disease is the sixth leading cause of death in the US, and one in three people will die with it or some other form of dementia. Experts predict that number will increase over the next few years as the size and proportion of the population aged 65 and older increases.

Eating more seafood won’t guarantee protection against Alzheimer’s or some other form of dementia, but the evidence points to seafood as a weapon against it. In addition, getting regular exercise and eating plenty of plant foods rich in antioxidants can reduce your risk.

The study is published in the Journal of the American Medical Association.