Aging is characterized by an increase in chronic inflammation within the immune system. This so-called inflammaging can contribute to conditions associated with growing older, including dementia and cognitive impairment Much scientific evidence suggests that the nutrients in food can modulate both acute and chronic autoimmune responses.

Diet, a modifiable lifestyle factor, may be a useful tool to fight inflammation. “There may be some potent nutritional tools in your home to help fight the inflammation that may contribute to brain aging,” Nikolaos Scarmeas, corresponding author of a study recently done in Greece, told TheDoctor.

People who ate foods with the highest inflammatory index were three times more likely to develop dementia than those who ate a diet of foods with the lowest index.

The study looked at the association between the inflammatory potential of the diet, called a dietary inflammatory index, and the incidence of dementia among a group of older adults. Those people who ate foods with the highest inflammatory index were three times more likely to develop dementia than those who ate a diet of foods with the lowest index.

A food’s inflammatory index can range from -8.87 to 7.98, and higher numbers indicate foods more likely to cause and less likely to prevent inflammation. An inflammatory diet is one which includes little fruit, few vegetables and few legumes, such as beans, lentils, peas, as well as little tea and coffee.

Data from more than 1,000 people enrolled in the Hellenic Longitudinal Investigation of Aging and Diet were included in the study. The average age of participants was 73.

Participants filled out a food questionnaire about the main food groups they consumed during the previous month to determine the inflammatory potential of their diet. Multiple nutrients in all foods contribute to this inflammatory potential, Scarmeas explained. Many foods do little to inhibit inflammation; however, certain foods have high anti-inflammatory potential.

A diet high in inflammatory foods would include little fruit, tea and coffee, few vegetables and legumes (beans, lentils and peas).

People in the study were divided into three groups: those with the lowest dietary inflammatory index numbers, those with the middle numbers and those with the highest numbers. The group with the lowest inflammatory index ate about 20 servings per week of fruit, 19 servings of vegetables, four of beans and other legumes and 11 servings of coffee or tea per week. Those with the highest inflammatory indices ate only about nine servings of fruit each week, 10 of vegetables, two of legumes and nine servings of coffee or tea.

During the follow-up period, which lasted about three years, roughly six percent of the study participants — 62 people — developed dementia. Their average dietary inflammatory index was -0.06, while those who did not develop dementia had an average index that was much lower — -0.70. Each one-point increase in the inflammatory index was associated with a 21 percent increase in dementia risk.

The study was observational — though it shows a relationship between inflammatory foods and mental sharpness, its design was such that it could not prove that an inflammatory diet causes cognitive decline or dementia.

More and longer term studies are needed to better determine the mechanisms by which inflammation, including the inflammatory potential of nutrients in the diet, contributes to cognitive decline, Scarmeas, of National and Kapodistrian University in Athens, explained, adding, “Dementia is a multifactorial process with many potential mechanisms involved, including oxidative stress and inflammation.”

The study is published in Neurology.