Improved diet and reduced waist-to-hip ratio associated with better cognitive and mental health: JAMA

A new study published in the Journal of American Medical Association showed that better diet and a reduced waist-to-hip ratio throughout middle age have been linked to improved cognitive and mental health as people age.

Lifestyle variables may be linked to dementia risk, according to epidemiological research. Few research, nonetheless, have looked at how nutrition and waist-to-hip ratio (WHR) relate to cognitive health and hippocampal connection. Therefore, this study was set to determine the relationship between hippocampal connection and cognitive performance in later life and longitudinal changes in food quality and WHR throughout midlife.

This cohort research examined data from participants in the University of Oxford's Whitehall II Imaging Substudy (2012-2016) and University College London's Whitehall II research (1985). Healthy Whitehall II Imaging Study individuals with a mean age ranging from 48 years at baseline to 70 years at magnetic resonance imaging (MRI) were included provided they had high-quality MRI scans, diet data from at least one wave, and WHR data from at least two waves. Analyses of the study were finished between October 2019 and November 2024. The Alternative Healthy Eating Index–2010 score, which was evaluated 3-times over an 11-year period, was used to examine the diet quality of individuals (mean age, 48 years at baseline to 60 years).

The main results were measures of cognitive performance, resting-state functional MRI for assessing hippocampus functional connectivity, and diffusion tensor imaging for assessing white matter structural connectivity. Cognitive tests and brain imaging were conducted at a mean (SD) age of 70 (5) years.

There were a total of 664 individuals in the final WHR sample and 512 participants in the final diet quality sample. Higher hippocampus functional connections to the occipital lobe and cerebellum, as well as greater white matter integrity as indicated by higher fractional anisotropy and lower diffusivity, were linked to improved food quality in midlife and from midlife to late age.

Higher midlife WHR was linked to reduced FA and higher MD and radial diffusivity in the corticospinal tract, which includes the cingulum and inferior longitudinal fasciculus and makes up 4.9% of the white matter skeleton. Diffusion acted as a partial mediating factor in the relationships among midlife WHR, working memory, and executive function.

Overall, it was discovered that midlife measurements of diet and abdomen fat (WHR intercepts) were linked to later-life hippocampus function and white matter connections. White matter diffusivity acted as a partial mediating factor in the link between higher WHR in midlife and worse working memory and executive function in later life.

Reference:

Jensen, D. E. A., Ebmeier, K. P., Akbaraly, T., Jansen, M. G., Singh-Manoux, A., Kivimäki, M., Zsoldos, E., Klein-Flügge, M. C., & Suri, S. (2025). Association of diet and waist-to-hip ratio with brain connectivity and memory in aging. JAMA Network Open, 8(3), e250171. https://doi.org/10.1001/jamanetworkopen.2025.0171