Healthier Diet, Lower WHR Improved Cognitive Brain Function
Researchers compared changes in diet quality and waist-to-hip ratio during midlife with that of hippocampal connectivity and cognitive function in later life.
Taking advantage of healthier diets and aiming to lower waist-to-hip ratio (WHR) in midlife translated to greater brain and cognitive health later in life, according to data published in JAMA Network Open.1 For populations aged 48 to 70 years old, researchers highlighted the cognitive benefits of improving diet and managing obesity.
“The global shift toward unhealthy dietary habits is associated with an increase in the prevalence of diabetes, cardiovascular disease, and obesity, all of which are known risk factors for dementia,” wrote authors of the study. “World Health Organization guidelines recommend a balanced diet with a high plant intake and weight management to reduce the risk of dementia. It is, therefore, important to consider the implications of overall diet and central obesity for memory and associated brain regions, such as the hippocampus.”
While patients with obesity are susceptible to various comorbidities, such as high blood pressure and type 2 diabetes, research shows a concerning link between obesity and cognitive health. Indeed, an Alzheimer’s Society analysis identified that patients with obesity between the ages of 35 and 65 are at a 30% risk of developing dementia at later ages in life.2
Study investigators found that both a lowered WHR and better diet quality resulted in improved brain function. | image credit: Tatiana Kolosovskaya / stock.adobe.com
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With a variety of previous research exploring obesity’s link to brain health, many findings have been inconsistent and require further evidence regarding obesity, dieting, cognitive functions, and diseases that impact the brain. In the current study, researchers decided to focus on the development of cognitive deterioration throughout life, identifying the transition period from middle to older age (ie, 40 to 70 years) as a key age group for their analysis.
“In this study, we aimed to ascertain the association of diet quality and WHR in midlife as well as their longitudinal changes during middle to older age with structural and functional connectivity of the hippocampus and cognitive function in later life,” continued the authors.1 To further their evidence regarding dieting and brain function, researchers collected comprehensive dietary questionnaire and WHR measurement data throughout a 21-year period during patients’ midlife.
Researchers collected data from the longitudinal Whitehall II Study, which followed over 10,000 patients throughout 30 years. During this time, patients were asked to report on both their dietary habits and WHR. Extracting data from the Whitehall study, the current study’s researchers were able to identify their patient population’s diet quality 3 times over 11 years as well as WHR measured 5 times over 21 years.
“Based on evidence linking brain connectivity to diet, body weight or obesity, and cognition, we tested mediation models to examine whether the observed associations between [the Alternative Healthy Eating Index–2010] or WHR and cognition were mediated by brain connectivity,” they wrote.
To assess changes in both diet and WHR, researchers included 2 separate cohorts consisting of patients that reported diet quality and those that reported WHR. In the diet cohort, they included 512 participants (mean age, 47.8 years at wave 3; 78.7% men) and 664 participants (mean age, 47.7 years at wave 3; 80.1% men) in the WHR cohort.
“Findings of this study showed that higher diet quality and lower WHR in midlife along with their improved trajectories from middle to older age were associated with structural and functional connectivity of the hippocampus at older ages,” they continued.1 “Furthermore, lower WHR in midlife was associated with better working memory and executive function later in life, and this pathway was mediated by white matter diffusivity.”
Confirming their hypothesis, study investigators found that both a lowered WHR and better diet quality resulted in improved brain function mediated by white matter diffusivity. They also found that lower WHR was specifically associated with better memory and function within the brain.
Finally, they discovered the inverse outcome that higher WHR led to poorer working memory and function in older age. With their extensive data collection of patients across 30 years, as well as identifying diet and weight measurements during this time, researchers were able to provide significant evidence regarding the brain’s development among midlife adults with obesity.
“These findings suggest that interventions to improve diet and manage central obesity might be best targeted in midlife (ages 48-70 years) to obtain beneficial outcomes for brain and cognitive health in older age,” concluded authors of the study.1
READ MORE: Obesity Management Resource Center
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