Dementia and diet have a cloudy but critical link. In a 2020 study, scientists dove into not just specific foods, but diets on more holistic level.
A number of studies have shown that eating a healthier diet — green leafy vegetables, berries, nuts, whole grains, fish — may reduce dementia risk. But often, scientists focused on quantity and frequency of certain foods. New research takes the question of diet a step further to food combinations.
A 2020 study published in Neurology looked at diet as a bigger picture, comparing dementia risk in people who ate different combinations of foods, both healthy foods and not. Findings indicate that, while it matters what foods you eat and in what quantities, how foods are combined are also a dementia risk factor.
“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,” said the study’s author Dr. Cécilia Samieri at the University of Bordeaux in France. “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.”
The study included just over 600 participants, average age 78, a third of whom with dementia and two thirds of whom without dementia. Five years prior, participants completed a food questionnaire about the types of food they ate over the course of a year, and how frequently, from less than once a month to more than four times a day.
Researchers used data from the food questionnaire and participants’ periodic medical check-ups to compare what foods were often eaten together by the patients who had dementia versus by those who did not.
“Processed meats were a ‘hub’ in the food networks of people with dementia,” said Samieri. “People who developed dementia were more likely to combine highly processed meats such as sausages, cured meats and patés with starchy foods like potatoes, alcohol, and snacks like cookies and cakes.”
The findings lead Samieri to believe that the frequency that processed meat appears in various combinations — rather than the quantity of processed red meat consumed — may be a risk factor: “For example,” she said, “people with dementia were more likely, when they ate processed meat, to accompany it with potatoes and people without dementia were more likely to accompany meat with more diverse foods, including fruit and vegetables and seafood.”
According to Samieri, the findings suggest that studying diet through the big-picture lens of food networks rather than focusing on individual foods or even more granularly on nutrients could help untangle the complexity of diet and biology in health and disease.