Maintaining cognitive health as we age is a growing concern, with researchers continuously exploring factors that influence brain function and neurodegeneration. A study published in the Journal of the American Medical Association has investigated the relationship between long-term diet quality, waist-to-hip ratio (WHR), and brain health, seeking to understand whether dietary habits and changes in body composition from middle age onward affect brain structure and cognitive performance.
The study followed participants from two distinct cohorts: one group focusing on diet quality and another on WHR. Researchers examined how these two factors evolved over time and their associations with various measures of brain health. This study specifically analyzed: the effect of diet quality (measured using the Alternative Healthy Eating Index 2010 (AHEI-2010), which assesses the nutritional value of an individual’s diet), the impact of WHR, (which reflects central fat distribution, on brain health.)
The research spanned multiple decades, with diet quality evaluated over three waves (from midlife into later years) and WHR monitored over a period of up to 21 years. Researchers then analyzed how these factors influenced the participants’ white matter integrity, brain connectivity, and cognitive performance in later life.
Maintaining a good diet from midlife onward does not necessarily correlate with better white matter health. However, individuals who improved their diet over time showed significant enhancements in brain structure. Increased scores on the AHEI-2010 (indicating a healthier diet) over the years were associated with better white matter microstructure, including higher fractional anisotropy (FA), lower mean diffusivity (MD), and reduced axial diffusivity (AD).
Individuals with a consistently high AHEI-2010 score demonstrated increased connectivity between the left hippocampus and occipital lobe, as well as between the left hippocampus and certain areas of the cerebellum. These regions are crucial for memory, visual processing, and higher cognitive function, suggesting that maintaining a healthy diet could contribute to better cognitive performance in aging.
Maintaining a healthy waist-to-hip ratio may be critical for preventing cognitive decline. The study indicates that increasing central adiposity over time is associated with widespread white matter damage and poorer cognitive performance. This highlights the importance of weight management as a strategy for preserving brain health. As research continues, the hope is that findings like these will help shape nutritional guidelines and lifestyle recommendations to promote healthy aging and cognitive resilience.
