Summary: New research suggests that dementia risk may be linked less to single foods and more to combinations of foods people habitually eat together. Diets dominated by highly processed meats, starchy side dishes, and sugary snacks were associated with a higher likelihood of a later dementia diagnosis compared with diets that included a wider variety of healthier foods.
Source: AAN
Diet quality can influence brain health, but a new study published online in Neurology on April 22, 2020, indicates the way foods are combined in a person’s diet—their “food networks”—may also matter. Researchers found that individuals whose diets clustered around processed meats, starchy foods such as potatoes, and sweet snacks were more likely to develop dementia years later than those whose eating patterns showed greater diversity and included more healthful items.
“A person’s diet is a web of interconnected choices. Understanding how these food connections—what we call food networks—relate to brain health could reveal new ways to prevent dementia,” said study author Cécilia Samieri, PhD, of the University of Bordeaux. “Previous studies often measured how much and how often single foods were eaten. We went a step further and examined how different foods are co-consumed, and we observed clear differences between people who later developed dementia and those who did not.”
The nested case-control study included 209 participants who developed dementia (average age 78) and 418 matched controls without dementia, matched by age, sex, and education. All participants had completed a detailed food-frequency questionnaire approximately five years prior, reporting how often they ate various foods over the previous year, from less than once a month to more than four times a day. Medical evaluations occurred every two to three years. The investigators used the dietary questionnaire to identify which foods were commonly consumed together and compared these food networks between cases and controls.
Although average intakes of individual foods differed little between the groups, their overall dietary patterns—identified as food networks—varied substantially. In people who later developed dementia, processed meats acted as a central “hub” in their food networks. These participants tended to pair processed meats (such as sausages, cured meats and pâtés) with starchy sides like potatoes, alcoholic drinks, and snack foods such as cookies and cakes. In contrast, those who did not develop dementia more frequently combined meat with a broader selection of accompaniments, including fruits, vegetables, and seafood.
“The data suggest that it may be the frequent combination of processed meats with other less healthy foods—not necessarily the sheer quantity of processed meat—that relates to dementia risk,” Samieri explained. “Dietary diversity appeared protective: people without dementia tended to have multiple small, disconnected food networks that included healthier choices like fruits, vegetables, fish, and poultry.”
The researchers observed that differences in food networks were detectable years before dementia was diagnosed, implying that eating patterns long before clinical onset may be relevant to prevention strategies. These findings support the idea that assessing dietary habits by how foods are consumed together—rather than only by amounts of single foods—can offer new insight into the relationship between diet and neurodegenerative disease.
Study limitations include reliance on a single food-frequency questionnaire, which depends on participants’ recall and captures diet at only one point in time; subsequent changes in eating habits were not recorded. In addition, participants were not monitored continuously, so the study cannot establish causation, only associations between food-network patterns and later dementia.
Funding: The research was funded by the Alzheimer’s Association. The broader 3-City Bordeaux cohort and related work received support from the INSERM Research Center at the University of Bordeaux, Sanofi-Aventis, the French Foundation for Medical Research, the French National Research Agency, the Plan Alzheimer Foundation, and other French organizations.
About this neuroscience research article
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AAN
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M.A. Rosko – AAN
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Original Research: Closed access
“Using network science tools to identify novel diet patterns in prodromal dementia” by Cécilia Samieri, Abhijeet Rajendra Sonawane, Sophie Lefèvre-Arbogast, et al., published in Neurology. DOI: 10.1212/WNL.0000000000009399
Abstract
Using network science tools to identify novel diet patterns in prodromal dementia
Objective
To apply network science methods to model complex dietary relationships up to a decade before dementia onset in a large French cohort (the 3-City Bordeaux study).
Methods
The investigators identified incident dementia cases after baseline dietary assessment and matched each case to two controls by age at diet assessment, sex, education, and season of survey. Food networks for cases and controls were inferred using mutual information to detect nonlinear associations, then compared to reveal differences in co-consumption patterns.
Results
In this nested case-control analysis (cases n = 209; controls n = 418), average follow-up and number of visits were similar between groups. Simple measures of average food intake showed few contrasts, but food networks differed markedly. Case networks were more focused and centered on charcuterie, linked to regional foods and snack items. Control networks displayed multiple disconnected subnetworks consistent with more varied and healthier dietary choices.
Conclusion
How foods are combined in habitual diets—not only the amounts consumed—may be important for dementia prevention. Predementia differences in dietary networks, indicating a tendency toward charcuterie and snacking, were apparent years before diagnosis. Network-based approaches, designed to model complex systems, can help clarify the role of diet in dementia risk.