People who consume diets rich in vitamins or omega-3 fatty acids are at reduced risk of developing Alzheimer's disease, finds to a new study.
This means people who regularly eat oily fish like salmon, mackerel and sardines or large amounts of fruit and vegetables could delay the disease or stop it developing.
So the scientists claimed that making simple changes in diet could prevent death from Alzheimer's disease.
Omega-3 fatty acids found in fish like salmon and mackerel have been shown to cut the risk of heart disease, help people recover from heart attacks, slow mental decline and reduce the risk of blindness.
Previous research has shown that eating fish can reduce people's risk of Alzheimer's disease by 47 per cent and even slow its progress.
But the latest study found that people with diets high in omega-3 fatty acids and in vitamins C, D, E and the B vitamins have higher scores on mental tests than people with diets low in those nutrients.
"Although there is no sure-fire way of preventing Alzheimer's yet, we know that risk factors for heart disease and stroke can also increase the risk of dementia," said Dr Simon Ridley, head of research at Alzheimer's Research UK.
"The best advice at the moment is to eat a balanced diet with plenty of fruit and vegetables, and keep healthy by not smoking, taking regular exercise and keeping blood pressure and cholesterol in check," he added.
The research was published in the online issue of Neurology, the medical journal of the American Academy of Neurology.