A new study suggests that high-fat foods like fish, berries, and nuts may help improve brain health in people at risk of Alzheimer’s.

A high-fat, low-carb diet (known as a ketogenic diet) may slow or halt the rate of cognitive decline in people at risk of Alzheimer’s, according to researchers at the University of Missouri.

The study, published in the journal Neurochemistry, examined whether the diet offered specific benefits to people born with the APOE4 gene. This gene is considered the most powerful genetic risk factor for developing Alzheimer’s later in life.

The APOE4 gene has previously been linked to early metabolic dysfunction in the brain and changes in gut bacteria.

Scientists say that targeting these early changes through diet could reduce the risk of Alzheimer’s disease in people who do not show symptoms.