Age-related brain atrophy, characterised by the gradual loss of neurons and reduction in brain tissue, naturally occurs as we age, potentially leading to cognitive decline and other neurological complications.
Although the ageing process is inevitable, a glimmer of hope arises from recent findings from an 18-month dietary intervention, suggesting that lifestyle and nutritional adjustments could decelerate brain ageing. This revelation comes from an international study spearheaded by Ben-Gurion University of the Negev, forming part of the DIRECT PLUS Brain MRI trial, highlighting the significant role of blood sugar control in maintaining brain health.
The study utilises MRI measurements of the hippocampus and lateral ventricles to evaluate ‘brain age’ — a concept that reflects the biological ageing of the brain, potentially differing from the individual’s chronological age. The chronological age measures the total number of years a person has lived, whereas brain age gauges the actual condition of the brain. Common signs of brain ageing include the shrinkage of the hippocampus and the expansion of the lateral ventricles. It’s not unusual for some individuals to exhibit a brain age that is either younger or older than their chronological age, with a younger brain age suggesting better cognitive health and an older one indicating accelerated ageing and a heightened risk of cognitive decline.
This study, recently published in The American Journal of Clinical Nutrition in 2024, was conducted by a global team of experts in brain health and nutrition, including researchers from prestigious institutions such as Harvard University, Leipzig University, and more. PhD student Dafna Pachter primarily undertook the research under the supervision of Professor Iris Shai and several international collaborators.
Building on a previous study from 2022, which demonstrated that the Mediterranean (MED) and green-MED diets substantially reduced age-related brain atrophy by approximately 50% within 18 months, the current research delves into understanding the mechanisms behind the slowing of brain atrophy. It found that reductions in HbA1c—a key marker of long-term blood sugar levels—are linked to significant positive changes in specific brain regions vulnerable to age-related atrophy. MRI results indicated lower HbA1c levels were associated with notable changes in the thalamus, caudate nucleus, and cerebellum—critical for cognitive functions, motor control, and sensory processing. The findings suggest that enhanced blood sugar management could be a pivotal factor in mitigating age-related changes in the brain.
The research also sheds light on the benefits of the Green Mediterranean (Green-Med) diet, which is known for improving blood sugar control and being rich in polyphenols from plant-based sources like Mankai (a high-protein aquatic plant) and green tea while low in red and processed meats. The study underscores that the Green-Med diet may bolster metabolic health and provide protective benefits for brain structure and function.
The DIRECT PLUS trial, one of the most extensive and prolonged brain MRI studies, involved 300 participants divided into three dietary groups. Whole-brain MRI measurements were conducted before and after the 18-month trial to monitor changes in brain health. Researchers employed Hippocampal Occupancy (HOC) to indicate brain age, which typically declines with age and can predict future dementia risk. Intriguingly, some participants displayed a brain age that was either younger or older than their chronological age.
The research team quantified and segmented data from brain MRIs using NeuroQuant, an FDA-authorized, fully automated tool. The study aimed to determine whether improved glycemic control and specific dietary components could slow brain ageing. The results indicated that participants who managed to enhance their blood sugar levels and achieve a normal glucose status experienced a more significant attenuation of brain ageing. Notably, those who consumed higher amounts of green tea and Mankai duckweed shakes saw the most critical improvements in blood sugar levels and brain health.
Professor Iris Shai, the study’s lead researcher from Ben-Gurion University, also an adjunct professor at Harvard University and an Honorary Professor at Leipzig University, explains, “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. Specifically, polyphenols found in plant-based foods may cross the blood-brain barrier and help reduce brain inflammation, which is crucial for memory.”
Dafna Pachter, the PhD student and first author of the paper, concludes, “This trial offers a safe approach to potentially slow down our brain ageing—by adopting the components of a green-Mediterranean diet.” This groundbreaking research opens new avenues for combating age-related brain deterioration through dietary strategies that enhance overall brain health and function.
More information: Dafna Pachter et al, Glycemic control contributes to the neuroprotective effects of Mediterranean and green-Mediterranean diets on brain age: the DIRECT PLUS brain-magnetic resonance imaging randomized controlled trial, American Journal of Clinical Nutrition. DOI: 10.1016/j.ajcnut.2024.09.013
Journal information: American Journal of Clinical Nutrition Provided by Ben-Gurion University of the Negev
