Researchers at the University of Illinois at Chicago School of Public Health received a $3.8 million grant from the National Heart, Lung and Blood Institute to study the effect of the Mediterranean diet and weight loss on cognitive function in obese older adults.
The study, which is led by the school’s Institute for Health Research and Policy, will follow a group of 180 ethnically diverse men and women for eight months to determine whether adherence to the Mediterranean diet—with and without weight loss—improves performance on cognitive tasks, such as memory and attention. Dr. Marian Fitzgibbon, deputy director of the IHRP and professor of pediatrics in the UIC College of Medicine, is principal investigator on the study.
“We know there is an association between obesity and cognitive decline, but we do not know the extent to which changes in diet can lead to better cognitive health,” Fitzgibbon says. “By looking at the Mediterranean diet in a randomized, controlled clinical trial, we will be able to learn if diet is the driver of improved cognitive function, or if the mechanism is the combination of diet and weight loss.”
The Mediterranean diet includes a high intake of vegetables, fruits, whole grains, unsaturated fatty acids and modest alcohol consumption — usually wine — with meals. Previous studies have shown the Mediterranean diet to be associated with reduced risk of cognitive impairment and dementia. But there have been no randomized, controlled trials to determine causality or suggest specific clinical recommendations.
“Identifying lifestyle-based interventions that could delay the onset of cognitive decline is a critical public health priority,” Fitzgibbon said, because there are no drug treatments to offset the mental deterioration of Alzheimer’s. An effective dietary approach, she said, would be “an incredible boon for people as they age and look for ways to prevent or slow the onset of cognitive decline.”
Co-investigator Dr. Melissa Lamar, director of cognitive aging and vascular health at UI Health and associate professor of psychology and psychiatry in the UIC College of Medicine, says cognitive neurodegeneration and the risk of dementia is a significant challenge in the U.S. and worldwide, particularly when it comes to minority groups in the U.S.
More than 20 percent of older adults exhibit signs of cognitive impairment, and the Alzheimer’s Association estimates that the prevalence of Alzheimer’s disease in African Americans over 65 is approximately twice that of non-Hispanic whites. The prevalence in Hispanics is approximately 50 percent greater than in whites.
To participate in the study, obese adults 55 and older will undergo an initial screen and baseline measurements, both physical and cognitive, before being randomized into one of three groups. One group will be assigned to follow the Mediterranean diet with active weight loss strategies; another group will be assigned to follow the Mediterranean diet without attempting to lose weight; and a third group will serve as a control and not make any dietary changes. During the eight-month trial, participants assigned to follow a Mediterranean diet will attend group intervention sessions and classes through the Chicago Park District that focus on changing lifestyle patterns.
Researchers will conduct an assessment of physical and cognitive health at the end of the trial and a follow-up assessment six months later. Both assessments will be compared with the baseline to determine if cognitive function has improved.
Fitzgibbon and Lamar will work with UIC College of Medicine colleagues Drs. Lisa Tussing-Humphreys, Marcelo Bonini, Giamila Fantuzzi and John Tulley.