Can certain foods stave off dementia?

Here’s what science says about whether adding walnuts or olive oil to your diet can counteract cognitive decline

Walnuts can improve cognitive function. Blueberries boost can memory. Fish oil supplements can lower your risk of Alzheimer's disease.

You may have noticed these buzzy 'brain food' claims scattered across online health articles and social media feeds. But can certain foods or diets really stave off or prevent dementia?

'Brain-boosting' diet

Scientists don't yet know for certain what causes Alzheimer's disease, the most common form of dementia. And there is no medication that can reverse it, said Dr Uma Naidoo, director of nutritional and metabolic psychiatry at Massachusetts General Hospital, US.

Two diets in particular, the Mediterranean diet and the MIND diet both of which encourage fresh produce, legumes and nuts, fish, whole grains and olive oil-have been shown in scientific studies to offer strong protection against cognitive decline.

"Pretty much anything that will help keep arteries healthy will reduce risk of dementia," said Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard TH Chan School of Public Health, US.

1 Leafy greens