While it's not possible to stop the brain from aging – at least not yet – there might be ways to slow down its decline, and a new study shows the vital role blood sugar levels play in how rapidly the brain ages.
The study is the work of an international team of researchers following up on a 2022 paper that looked at links between diet and brain atrophy. In the previous research, the Mediterranean diet, and particularly the green Mediterranean diet (more plants, less meat), were associated with less wear and tear on the brain.
In this new study, the team wanted to examine some of the mechanisms that might be behind that association. They found a significant relationship between lower blood sugar level markers, and less of the brain shrinkage and neuron death that typically happens as we get older.
"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," says senior author of the study and epidemiologist Iris Shai, from Ben-Gurion University in Israel.
Data was collected via magnetic resonance imaging ( MRI) brain scans of 224 participants, averaging around 51 years of age, and diagnosed as obese or having high levels of fat in their blood. Across the course of 18 months, they were split into three groups, and then put on a Mediterranean diet, a green Mediterranean diet, or a standard healthy diet.
Given that slower brain aging was significantly associated with the Mediterranean diets (especially the green one), and lower blood sugar levels, it's likely that all three factors are linked – with the previous 2022 study offering further supporting evidence.
The researchers noticed that volunteers who consumed plenty of green tea and Mankai duckweed shakes as part of the green Mediterranean diet tended to show the least amount of brain tissue wear. That hints that there's something about plant-based food that protects the brain.
"Specifically, polyphenols found in plant-based foods may cross the blood-brain barrier and help reduce brain inflammation, which is crucial for memory," says Shai.
While we can't infer direct cause and effect from the data, there's a strong indication that Mediterranean diets are good for the brain – as shown by several past studies. Within that, it seems to be low sugar levels and high plant content that are the main driving forces.
Brain aging is a natural part of getting older to some extent, but faster aging means we're more at risk of cognitive decline and related neurological diseases at an earlier stage of life. Knowing more about why this happens puts us in a better position to be able to do something about it – like changing our diet.
"This trial offers a safe approach to potentially slow down our brain aging – by adopting the components of a green Mediterranean diet," says lead author of the study and epidemiologist Dafna Pachter, from Ben-Gurion University.
The research has been published in the American Journal of Clinical Nutrition.
