Can what you eat influence the health of your brain now and in the future?
That is a key question that USF Health Morsani College of Medicine researchers hope to answer with the help of a noninvasive Microbiome in the Aging Gut and Brain (MiaGB) study.
The new clinical study expects to enroll 400 adults ages 60 and older in the Tampa Bay region and beyond — both those who are cognitively healthy as well as those diagnosed with mild cognitive impairment and early-stage dementia.
The researchers will analyze the composition of bacteria in stool samples and saliva samples (oral swabs) donated by study participants, one time at the beginning of the study, and then once a year for at least five years. They will track alterations over time in the populations of oral and gut microorganisms, collectively known as the microbiome. Using an interactive mobile app, study participants will complete a daily dietary recall questionnaire and yearly tests of their memory, speed of thinking, and other cognitive abilities.
“We want to know, based on changes in the microbiome ‘signature’ from the saliva and stool samples, if we can predict an older person’s risk of developing cognitive decline or dementia. And can we do that early enough to delay or prevent those age-related diseases – either by modifying the individual’s diet or the microbiome itself,” said Hariom Yadav, PhD, an associate professor of neurosurgery and brain repair at the Morsani College of Medicine and director of the USF Center for Microbiome Research.
Several studies have correlated healthy guts, characterized by a well-balanced diversity of microorganisms, with healthy aging. Alzheimer’s disease and other dementias are among the growing number of medical conditions linked to an imbalance of microorganisms (more bad bugs than good bugs) within the intestines. Emerging evidence also suggests that oral health and brain health are interconnected, including a large National Institute on Aging study last year linking gum disease with dementia.
The daily food intake logged by study participants will indicate any deficiencies in their usual diets, said Shalini Jain, PhD, the MiaGB study’s IRB principal investigator and USF Health assistant professor of neurosurgery and brain repair. “We’ll be able to evaluate the effects that certain types of foods (i.e, protein, fruits, vegetables, dairy, carbohydrates, fermented foods, and junk food) have on the growth of certain types of bacteria and see how the mix of bacteria changes if the diet is modified.”
Study participants may benefit by learning more about the calories and nutritional balance (or imbalance) in their diets, Dr. Jain added. Based on the dietary information reported, the mobile app suggests healthy habits that can be incorporated into the individual’s lifestyle.
Aging is not a disease, Dr. Yadav emphasized, but as people age, it’s particularly important to keep a healthy balance of intestinal microbes so that a potentially harmful strain of bacteria does not overgrow and monopolize the food source of beneficial bacteria. “A healthy gut allows you to adequately absorb the healthier nutrients and keep a check on the stimulation of inflammation, which is a root cause of several age-related conditions, including abnormal cognitive function,” he said.
