Lack of variety in diet could contribute to dementia, study finds

A new study has revealed that the variety and combinations of food people eat could affect the chances of them developing dementia in later life.

While the link between diet and the health of the brain has been long established, the new analysis by French scientists, published in Neurology, the journal of the American Academy of Neurology, looked specifically at 'food networks' and how the amount of diversity in a person's diet contributed to any cognitive decline.

Although some of its findings are familiar and reiterate what is well known, such as the link between high consumption of processed foods and dementia, it sought to go further by looking deeper at how these foods are consumed.

Study author Cécilia Samieri, PhD, of the University of Bordeaux in France, explained: "There is a complex inter-connectedness of foods in a person's diet, and it is important to understand how these different connections, or food networks, may affect the brain because diet could be a promising way to prevent dementia."

While the researchers found there were few differences in the amount of individual foods that people ate, overall food groups or networks differed significantly between people who had dementia and those who did not have dementia.

For example, the study found processed meats such as sausages, bacon and pates were a 'hub' food in the networks of people with dementia. These individuals were also more likely to consume these foods alongside starchy options like potatoes, alcohol, and snacks such as biscuits and cakes.

People who did not develop dementia, however, were more likely to have greater diversity in their diet, as they typically had a much wider variety of smaller food networks, with less reliance on a few key hubs.

While these individuals may still consume some processed foods, they were also more likely to include options such as fruit and vegetables, seafood and poultry to accompany the less healthy choices.

The study said this may suggest that it is the frequency with which processed meat is combined with other unhealthy foods, rather than the average quantity, that is important for identified dementia risk.

Dr Samieri added: "We found that more diversity in diet, and greater inclusion of a variety of healthy foods, is related to less dementia. In fact, we found differences in food networks that could be seen years before people with dementia were diagnosed.

"Our findings suggest that studying diet by looking at food networks may help untangle the complexity of diet and biology in health and disease."

The study consisted of 209 people with an average age of 78 who had dementia and 418 people, matched for age, sex and educational level, who did not have dementia. At the start of the five-year study, they were asked to complete a food questionnaire describing not only what types of food they ate over the course of a year, but also how frequently, from less than once a month to more than four times a day. They also had medical checks every two to three years.

Researchers used this data to compare what foods were often eaten together by the patients with and without dementia.