Brain changes from diabetes: MRI scans show adverse health effects from longer sickness duration

11 Aug 2023 --- US-based researchers have found study participants who had Type 2 diabetes for a longer period of time had a higher risk of experiencing changes in the brain such as decreased mean cortical thickness and gray matter volumes – the death of brain cells. 

Nutrition Insight speaks with co-author Dr. Eva Feldman, professor of Neurology and director of NeuroNetwork for Emerging Therapies and ALS Center of Excellence at Michigan Medicine, University of Michigan, US, about the results.

“Decreased mean cortical thickness and gray matter volumes translate into less live ‘brain’ cells in the brain – suggesting brain cells have died and are unavailable to provide their normal function,” explains Feldman.

“This [less brain cells] includes [symptoms of] decreased cognition, specifically short and long-term memory, judgment, orientation and reasoning. An increased volume of white matter hyperintensities is strongly linked to dementia and is believed to be markers of cerebrovascular disease, particularly untreated hypertension and smoking.”

The toolbox
The researchers used the National Institute of Health (NIH) Toolbox Cognitive Battery – language and memory tests and MRI scans – to observe the relationship between diabetes and cognition. The study had 51 middle-aged participants, all diagnosed with Type 2 diabetes.

The adverse effects on the brain for people with diabetes were shown in the MRI scans, although cognition did not show a decline which “is surprising,” the researchers note.

“This is among the first times that alterations of the brain’s structure have been associated with the duration of diabetes,” says first author Dr. Evan Reynolds, research fellow and lead statistician for the NeuroNetwork for Emerging Therapies at Michigan Medicine, University of Michigan.

The researchers used language and memory tests and MRI scans to observe the relationship between diabetes and cognition.“Although we did not find reduced cognition through the NIH Toolbox, this might not give the entire picture. The fact that we saw negative changes in the brain provides evidence for early screening for cognitive disorders in patients with Type 2 diabetes to improve patient care and quality of life,” adds Reynolds.

However, another study found that 40-60-year-olds with diabetes have a 2.45 times higher likelihood of developing a cognitive disorder. Prior studies have also found a link between diabetes and structural changes in the brain, nerve damage in the heart and blood vessels and chronic kidney disease, say the researchers.

“This study is critical to our understanding of how diabetes affects brain health and lays the groundwork for a larger, longitudinal study addressing how persons with diabetes can maintain a healthy brain,” says Feldman.

“Regardless of the underlying mechanisms, preventing these conditions in people with Type 2 diabetes is critical to maintaining brain health. Educating the public on the risks that diabetes poses to preserving a healthy brain is part of our mission.”

The study was published in Annals of Clinical and Translational Neurology.

Nutritional guidance
Feldman explains the nutritional guidelines for diabetic patients are those of the American Diabetes Association (ADA) and essentially consist of the Mediterranean diet, which includes a sufficient consumption of fruits and vegetables, lean meats and plant-based protein sources, less added sugar and processed foods. 

“The ADA suggests plenty of non-starchy vegetables such as broccoli, green beans, kale and salad greens. Lean protein foods including meat, chicken, fish, shellfish, eggs, cheese, nuts, seeds and plant-based protein foods like soy and beans are included in differing proportions,” details Feldman.

She underscores that the study did not address any nutritional deficiencies.

“We did look at diabetes control and the levels of blood fats (lipids) in our patients – along with other metrics of the metabolic syndrome, defined as diabetes, hypertension, high blood levels and obesity.”

Recently, Malaysia-based PhytoGaia presented a meta-analysis on vitamin E, linking palm tocotrienols/tocopherol complex supplementation to a significant reduction in HbA1c, which might be helpful for those suffering from Type 2 Diabetes Mellitus as it may prevent cardiac mortality and micro- and macrovascular problems. 

By Beatrice Wihlander