Another Benefit of Long-term Weight Loss

May 13, 2016

Researchers measured cognitive function in diabetic patients to study the effects of losing weight and increasing physical activity on brain health.

Long-term weight loss may help prevent the brain damage and cognitive decline caused by type 2 diabetes mellitus (T2DM), according to a new study.

The results suggest that losing weight and increasing physical activity can lead to long-term benefits in brain health.

Behavioral interventions to promote weight loss through dietary changes and increased physical activity may delay increases in the accumulation of brain white matter hyperintensities and loss of brain tissue among patients with T2DM, according to researchers, led by Mark Espeland, PhD, Professor of Public Health Sciences at Wake Forest School of Medicine in Winston-Salem, NC.

Espeland and colleagues assessed whether participation in a successful 10-year lifestyle intervention was associated with better profiles of brain structure. They studied participants enrolled in the Action for Health in Diabetes clinical trial, who had T2DM, were overweight or obese, and were aged 45–76 years.

The participants were randomly assigned to receive 10 years of lifestyle intervention, including group and individual counseling, or to a control group that received diabetes support and education through group sessions on diet, physical activity, and social support. Those in the intensive counseling group were encouraged to eat calorie-restricted diets with limited amounts of fats and proteins and to set exercise goals of at least 175 minutes a week of moderate activity, such as brisk walking.

The intensive counseling group met weekly initially and then had monthly meetings. The control group was invited to attend group classes a few times a year.

Following this intervention, 319 participants from 3 sites underwent standardized structural brain magnetic resonance imaging and tests of cognitive function 10–12 years after randomization.

In the first year, the intensive counseling group lost about 12% of their weight, on average, as compared with less than 1% in the control group. Cardiorespiratory fitness improved about 26% for the intensive counseling group as compared with 7% among controls.

Total brain and hippocampus volumes were similar between the two groups. However, the mean white matter hyperintensity volume, which normally changes with age and can be worsened by diabetes, was 28% lower among the lifestyle intervention participants as compared with those receiving diabetes support and education.

The mean ventricle volume, another indicator of brain deterioration, was 9% lower for the intensive counseling group.

At the end of the study, both groups had similar cognitive function, however, those in the lifestyle intervention group showed better performance on tests of attention and processing speed.

The results suggest that weight loss and other lifestyle changes may help reduce high glucose levels that can become toxic to the brain.

There were some limitations of the study, the researchers noted. They did not examine other factors that might lead to better diabetes control and potentially protect the brain, such as blood pressure, sleep apnea, depression, medication use, and inflammation.

The researchers concluded that “long-term weight loss intervention may reduce the adverse impact of diabetes on brain structure. Determining whether this eventually delays cognitive decline and impairment requires further research.”

Reference: Espeland MA, et al. Brain and white matter hyperintensity volumes after 10 years of random assignment to lifestyle intervention. Epub 29 Mar 2016.