Midlife Diet Quality Linked to Brain Changes in Later Life

TOPLINE:

Maintaining a healthy diet and a lower waist-to-hip ratio (WHR) throughout midlife was associated with improved brain health and cognitive function in older age in a new cohort study.

METHODOLOGY:

• Researchers analyzed data from the Whitehall II Study (inception: 1985) at University College London, London, and the Whitehall II Imaging Substudy (2012-2016) at the University of Oxford, Oxford, the United Kingdom.
• Overall, 512 participants (mean age, 47.8 years; 79% men) were included in the diet quality sample, and 664 participants (mean age, 47.7 years; 80% men) were included in the WHR sample.
• Scores on the Alternative Healthy Eating Index–2010 (AHEI-10) were assessed three times over 11 years in participants aged 48-60 years, while WHR was measured five times over 21 years in participants aged 48-68 years.
• Outcome measures included white matter structural connectivity via diffusion tensor imaging, hippocampal functional connectivity via resting-state functional MRI, and cognitive performance tests at the mean age of 70 years.

TAKEAWAY:

• Better diet quality in midlife was significantly associated with enhanced hippocampal functional connectivity to the occipital lobe and cerebellum, with the left hippocampus showing a volume of 9176 mm³ (P < .05). Connectivity between the left hippocampus and the right cerebellum was 136 mm³ (P = .04).
• A higher WHR in midlife was associated with increased mean diffusivity and radial diffusivity, covering 26.4% (333,088 mm³; P < .001) and 23.1% (291,888 mm³; P < .05) of the total white matter tracts, respectively.
• A higher WHR was also linked to significantly lower cognitive performance scores on a number of tests, including verbal episodic memory (false discovery rate-corrected P = .003), digit span (P = .002), and semantic fluency (P = .007).
• The association between midlife WHR, working memory, and cognitive function was partially mediated by white matter diffusivity.

IN PRACTICE:

“These findings suggest that interventions to improve diet and manage central obesity might be best targeted in midlife (age, 48-70 years) to obtain beneficial outcomes for brain and cognitive health in older age,” the investigators wrote.

In an accompanying editorial, Sharmili Edwin Thanarajah, MD, University Hospital Frankfurt, Frankfurt, Germany, wrote, “There is a growing body of evidence suggesting that a substantial percentage of dementia may be prevented through the management of modifiable risk factors in middle age.” She added that the new study has “important implications for prevention strategies,” including the improvement of metabolic health. 

SOURCE:

The study was led by Daria E. A. Jensen, DPhil, University of Oxford. The study and the editorial were published online on March 12 in JAMA Network Open.

LIMITATIONS:

Dietary data were self-reported via a semiquantitative Food Frequency Questionnaire, which may have introduced errors. The AHEI-2010 score used to assess diet quality may not have fully captured all dietary habits. The predominantly male cohort limited sex-specific comparisons. Additionally, the cohort included largely White British individuals, who were highly educated and healthier than the general UK population, potentially limiting generalizability.

DISCLOSURES:

The study was funded by the National Institute for Health and Care Research Oxford Health Biomedical Research Centre and the Wellcome Centre for Integrative Neuroimaging. Several investigators reported receiving grants, fellowships, and awards from various sources during the study. Thanarajah reported receiving support and funding from several organizations. Full details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.