Summary: A large population study found that older adults who follow a diet high in vegetables, fruit, fish, nuts and whole grains tend to have larger brain volumes. The findings suggest diet quality may be linked to brain structure and age-related neurodegeneration.
Better diet quality—especially higher intakes of vegetables, fruit, nuts and fish—is associated with larger brain volumes in older adults, a Rotterdam Study analysis published in Neurology reports.
Researchers examined brain scans and detailed dietary information from 4,213 dementia-free participants in the Netherlands, with an average age of 66. The study evaluated overall diet quality using Dutch dietary guidelines and investigated whether people who followed healthier dietary patterns had larger brain tissue volumes on magnetic resonance imaging (MRI).
“People with greater brain volume have been shown in other studies to have better cognitive abilities,” said Meike W. Vernooij, MD, PhD, of Erasmus University Medical Center in Rotterdam. “These results support the idea that improving diet quality could be one strategy to help maintain thinking skills as people age, although more research is needed to confirm causality and to understand the mechanisms involved.”
Dietary intake was measured with a detailed questionnaire asking participants how often they ate nearly 400 different food items during the previous month. Investigators used those responses to calculate a diet quality score ranging from 0 to 14, based on adherence to national guidelines. The score rewarded higher intake of vegetables, fruit, whole grains, legumes, nuts, dairy, fish, tea and unsaturated fats, and penalized high intake of red and processed meat, sugary beverages, excess alcohol and salt. The average diet quality score among participants was seven.
All participants underwent brain MRI to measure total brain volume, gray and white matter volumes, hippocampal volume, and to detect focal vascular lesions such as white matter lesions, lacunes and cerebral microbleeds. The average total brain volume in the group was 932 milliliters. The analysis accounted for head size and adjusted for other factors known to influence brain structure, including age, sex, education, blood pressure, smoking and physical activity.
After these adjustments, higher diet quality scores were linked with larger total brain volume, gray matter volume, white matter volume and hippocampal volume. On average, participants with better diets had approximately two milliliters more total brain volume than those with lower diet scores. For context, a decrease of about 3.6 milliliters in brain volume has been estimated to correspond roughly to one year of aging.
The association between diet and brain volume did not appear to be driven by a single food group. Instead, several food categories—particularly greater consumption of vegetables, fruit, whole grains, nuts, dairy and fish combined with lower intake of sugar-sweetened beverages—were each associated with larger brain volumes. When investigators applied a Mediterranean diet assessment, which emphasizes vegetables, fish and nuts, the results were similar to those seen with adherence to the Dutch dietary guidelines.
Notably, diet quality was not associated with measures of small vessel disease on MRI: white matter lesion volume, lacunes or cerebral microbleeds showed no clear relationship with diet in this cross-sectional analysis.
The authors emphasize several important limitations. The study is observational and cross-sectional, meaning it captures a single point in time and cannot prove that a healthier diet causes larger brain volume. Dietary intake was self-reported and relied on participants’ recall of their food consumption over one month, which can introduce measurement error. Additionally, the study population was Dutch, and results may not generalize to all populations or ethnic groups.
Despite these caveats, the findings add to a growing body of evidence suggesting that overall dietary patterns—rather than any single food—may influence brain structure and potentially reduce risk factors for age-related cognitive decline. The researchers recommend further longitudinal and mechanistic studies to determine whether improving diet quality earlier or later in life can slow neurodegeneration and preserve cognitive function.
Study: Better diet quality relates to larger brain tissue volumes: The Rotterdam Study (population-based analysis of 4,213 participants).
Published in: Neurology (online May 16, 2018).
Key takeaway: Higher adherence to dietary guidelines characterized by vegetables, fruit, nuts, whole grains, dairy and fish is associated with larger brain tissue volumes, while diet was not linked to focal small-vessel lesions on MRI.
Limitations: Cross-sectional design, self-reported diet, and study population limited to the Netherlands.
Abstract (summary)
Objective: To investigate associations between overall diet quality and structural brain volumes and focal vascular lesions in a dementia-free population.
Methods: From the Rotterdam Study, 4,447 participants underwent dietary assessment and brain MRI between 2005 and 2015; after exclusions, 4,213 participants were analyzed. A diet quality score (0–14) reflected adherence to Dutch dietary guidelines. MRI provided measures of brain tissue volumes, white matter lesion volume, lacunes and cerebral microbleeds. Multivariable regression assessed associations of diet quality and food groups with brain structure.
Results: Better diet quality was associated with larger total brain, gray matter, white matter and hippocampal volumes. Diet quality was not related to white matter lesion volume, lacunes or microbleeds. Higher intake of vegetables, fruit, whole grains, nuts, dairy and fish and lower consumption of sugar-containing beverages were associated with larger brain volumes.
Conclusions: A higher-quality diet is linked with larger brain tissue volumes, suggesting nutrition may influence neurodegeneration via brain structure. Longitudinal research is needed to clarify direct and indirect effects of diet on brain health.