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Blood sugar levels play a key role in brain aging: Can diet slow cognitive decline?

According to the study, individuals at risk for cognitive decline should prioritize blood sugar management through diet and lifestyle choices.

By Pesach Benson, TPS

The body’s blood sugar level is known to be linked to brain atrophy, and now findings from a team of international researchers suggest that dieting can slow the brain’s aging process.

Age-related brain atrophy, characterized by the gradual loss of neurons and shrinkage of brain tissue, is an inevitable aspect of aging.

This decline can lead to various cognitive impairments and neurological issues. While aging cannot be halted, the results from this 18-month dietary intervention suggest that adopting a healthier lifestyle can mitigate some effects of brain aging.

Brain age, determined through MRI assessments of the hippocampus and lateral ventricles, reflects the brain’s biological aging, which may not always align with a person’s chronological age.

As individuals age, the hippocampus tends to shrink while the lateral ventricles expand, serving as indicators of brain health.

A younger brain age generally signifies better cognitive functioning, whereas an older brain age can signal increased vulnerability to cognitive decline.

The study, conducted by a collaborative team of brain and nutrition experts, including researchers from Ben-Gurion University, Harvard University, and Leipzig University, was recently published in The American Journal of Clinical Nutrition 2024, a peer-reviewed journal.

The research was primarily led by Ben-Gurion PhD student Dafna Pachter and supervised by Prof. Iris Shai.

According to the study, individuals at risk for cognitive decline should prioritize blood sugar management through diet and lifestyle choices.

The findings indicate that lower levels of HbA1c — also known as glycated hemoglobin — correlates with significant positive changes in specific brain regions commonly affected by aging.

MRI results demonstrated that lower HbA1c levels were associated with greater changes in the thalamus, caudate nucleus, and cerebellum—key areas responsible for cognitive function, motor control, and sensory processing.

The research suggests that improved blood sugar management could be a pivotal factor in decelerating age-related brain changes.

Earlier studies have highlighted the advantages of the Green Mediterranean diet, which is rich in polyphenols derived from plant-based sources like Mankai (a high-protein aquatic plant) and green tea, while being low in red and processed meats.

The study reinforces the notion that the Green Mediterranean diet not only promotes metabolic health but may also offer protective benefits for brain structure and function.

The DIRECT PLUS trial, noted for being one of the longest and largest brain MRI intervention studies, involved around 300 participants divided into three dietary groups.

Whole-brain MRI measurements were taken before and after the 18-month trial to assess changes in brain health.

Using Hippocampal Occupancy (HOC) as a proxy for brain age, the study predicted future dementia risk. Interestingly, some participants displayed brain ages that were either younger or older than their chronological ages.

Employing NeuroQuant, an FDA-authorized automated tool, the research team quantified and analyzed the MRI data.

The goal was to examine the impact of dietary components and glycemic control on brain aging. Results indicated that participants who improved their blood sugar levels and achieved normal glucose status showed a more pronounced reduction in brain aging.

Notably, those who incorporated higher amounts of green tea and Mankai duckweed shakes into their diets experienced the most significant improvements in both blood sugar regulation and brain health.

Lead researcher Prof. Iris Shai of Ben-Gurion University explained, “Maintaining low blood sugar levels, even within the normal range, shows promise for preserving a younger brain, especially when combined with a healthy diet and regular physical activity. Polyphenols in plant-based foods may cross the blood-brain barrier, reducing inflammation crucial for memory.”

This study is among the first large-scale trials to establish a direct connection between dietary changes, particularly those related to the Green Mediterranean diet, improved glycemic control, and slower brain aging.

While further investigation is necessary, the research could encourage healthcare professionals to integrate nutritional counseling into their practices, emphasizing the role of diet in mental wellness.