Frequent consumption of these unhealthy foods is more important than the risk of dementia

"Our study shows that the combination of foods consumed is very important in preventing dementia," said Cecilia Samiri, head of the research team at the University of Bordex in France.

Dementia is more common in people who eat mostly processed meats such as hamburgers and sausages, starches such as potatoes, and snacks such as cakes and cookies.

The findings show that people with dementia usually have a diet rich in fruits, vegetables, seafood and chicken.

According to researchers, dementia, including Alzheimer's disease, can begin decades before symptoms appear, and a long-term diet plays an important role.

"Bad eating habits toward cold-cooked meats and snacks were evident in our group years before the dementia was diagnosed," Samiri added. "On the contrary, a varied and healthy diet reduces the risk of dementia."

The study looked at 209 people with dementia and 418 people without the disease in France. The average age of the people was 78 years and they were monitored for 12 years. Five years earlier, the men had completed a questionnaire on nutrition.

Researchers have found that before the onset of dementia, the diet of people with the disease was very different from that of people with dementia.

"We've also found that a diet rich in leafy vegetables, berries, nuts, whole grains, and fish reduces the risk of dementia," Samiri said.

"Frequent consumption of these unhealthy foods is more important than the risk of dementia," he said.