A new cohort study reveals that maintaining a healthy diet and a lower waist-to-hip ratio (WHR) during midlife may improve brain health and cognitive function in older age.
Study Overview
Researchers from University College London and University of Oxford conducted the study using data from the Whitehall II Study, which began in 1985. The study examined the health outcomes of 512 participants (mean age 47.8 years; 79% male) for diet quality and 664 participants (mean age 47.7 years; 80% male) for waist-to-hip ratio (WHR) over multiple years.
The study measured participants’ diet quality three times over 11 years, using the Alternative Healthy Eating Index–2010 (AHEI-10), and their WHR five times over 21 years. The outcome measures were assessed at a mean age of 70 and included brain imaging techniques and cognitive performance tests.
Key Findings
Diet Quality and Brain Health: The study found that better diet quality during midlife was linked to stronger hippocampal functional connectivity, specifically with the occipital lobe and cerebellum. The left hippocampus showed a volume of 9176 mm³ (P < 0.05), while connectivity between the left hippocampus and right cerebellum was 136 mm³ (P = 0.04).
Impact of WHR on White Matter and Cognitive Performance: A higher WHR in midlife was associated with increased mean diffusivity and radial diffusivity in white matter, covering 26.4% (333,088 mm³; P < 0.001) and 23.1% (291,888 mm³; P < 0.05) of total white matter tracts, respectively. Additionally, higher WHR was linked to poorer cognitive performance, including declines in verbal episodic memory, digit span, and semantic fluency.
White Matter Diffusivity and Cognitive Decline: The association between higher WHR and cognitive decline was partly explained by changes in white matter diffusivity.
Implications for Health Interventions
The study suggests that interventions aimed at improving diet quality and managing central obesity during midlife (ages 48-70) could help promote better brain and cognitive health in later years. Researchers emphasize that addressing these factors in midlife may reduce the risk of cognitive decline in older age.
Dr. Sharmili Edwin Thanarajah, MD, from University Hospital Frankfurt, Germany, noted in an editorial that this research contributes to a growing body of evidence suggesting that managing modifiable risk factors in middle age can prevent or delay the onset of dementia. She highlighted the importance of improving metabolic health as part of prevention strategies.
Study Limitations
There are several limitations to the study. Dietary data were self-reported via a semiquantitative Food Frequency Questionnaire, which may introduce errors. The AHEI-2010 score used to assess diet quality may not fully represent participants’ dietary habits. Additionally, the study cohort was predominantly male and consisted largely of White British individuals, which may limit the generalizability of the findings to other populations.
Conclusion
This study underscores the importance of a healthy diet and managing waist-to-hip ratio during midlife for maintaining brain health and cognitive function as we age. Early interventions targeting these factors could offer significant benefits in preventing cognitive decline in older adults.
Related topics: