There is growing evidence that a healthy diet is important for cognitive health. These benefits have often been attributed to important nutrients present in healthy diets, such as vitamins and omega-3 fatty acids, which play important roles in supporting brain cell function and controlling inflammation. A study recently published in the journal Neurology reported that a better diet quality is also associated with larger brain tissue volumes .
The results come from a large study of 4,213 Dutch people over the age of 45 who were free of dementia. Participants answered a questionnaire on the food and drink items they consumed, the number of servings per day, and the frequency of consumption. Based on their answers, a diet quality score in line with Dutch dietary guidelines was calculated for each participant. Then they underwent a brain MRI scan from which information on brain tissue volume and cerebral small vessel disease (e.g., lacunes, brain microbleeds, and white matter lesions) was obtained.
Researchers found that a higher score on diet quality correlated with a larger total brain volume. They specifically found that a higher score was associated with a larger hippocampus, a brain region important for memory functions. Notably, these associations were not driven by a single food group or drink. A higher intake of vegetables, fruits, whole grains, nuts, dairy, and fish, and a lower intake of sugar-containing beverages were associated with larger brain volumes. However, researchers did not find an association between diet quality and protection from cerebral small vessel disease.
Because this study was an observational study, it was not designed to prove cause and effect. People who eat a healthy diet may be more likely to have other healthy habits that may promote brain health, like physical exercise and cognitive engagement. It is worth emphasizing that the relationship between a healthy diet and larger brain volume remained significant even after controlling for factors such as physical activity, education, age, sex, calorie intake, smoking, and body mass index.
These results are in line with previous studies showing that adherence to the Mediterranean diet (rich in fish, nuts, vegetables, and fruit) protects against brain tissue loss . Results from a randomized controlled trial also showed that people eating the Mediterranean diet had higher blood levels of a protein called the brain-derived neurotrophic factor, which supports the growth and survival of brain cells .
Based on these studies, brain size may be driven by overall diet quality and not by a specific food item or drink, so it is important to eat a healthy balanced diet with lots of vegetables, fruits, fish, and legumes, and low levels of processed foods and sugars.
Yuko Hara, PhD, is Director of Aging and Alzheimer's Prevention at the Alzheimer's Drug Discovery Foundation. Dr. Hara was previously an Assistant Professor in Neuroscience at the Icahn School of Medicine at Mount Sinai, where she remains an adjunct faculty member. Her research focused on brain aging, specifically how estrogens and reproductive aging influence the aging brain's synapses and mitochondria. She earned a doctorate in neurology and neuroscience at Weill Graduate School of Medical Sciences of Cornell University and a bachelor's degree in biology from Cornell University, with additional study at Keio University in Japan. Dr. Hara has authored numerous peer-reviewed publications, including articles in PNAS and Journal of Neuroscience.
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