LLU Researcher Looks at Relationship Between Diet, Stress

LOMA LINDA>> Dr. Johnny D. Figueroa, PhD, an assistant professor at Loma Linda University School of Medicine, has published a paper on the effects of the typical, Western high-fat diet on one’s ability to respond to stress. The study, “Western high-fat diet consumption during adolescence increases susceptibility to traumatic stress while selectively disrupting hippocampal and ventricular volumes”, found that psychological trauma and obesity frequently occur together and are both major risk factors for psychiatric disorders. It was published in eNeuro, an open access journal of the American Society for Neuroscience. Figueroa, who served as principal investigator on the project, discovered that few studies have examined how obesity disrupts the brain’s ability to cope with stress. Two years ago, Figueroa began to investigate with colleagues Priya Kalyan-Masih, Julio David Vega-Torres, Christina Miles, Elizabeth Haddad, Sabrina Rainsbury, Mohsen Baghchechi and Andre Obenaus. All are affiliated either with the Center for Health Disparities and Molecular Medicine, the department of basic sciences, or the department of pediatrics at LLUSM. The team measured the results of the test in two ways: first, by monitoring two groups of subjects for trauma-induced anxiety-like behaviors; and second, by looking for changes in the size of relevant brain structures using magnetic resonance imaging, or MRI. The results were convincing. In terms of monitoring behavioral manifestations, Figueroa and his team found increased psychological trauma-induced anxiety-like behaviors in subjects that consumed the Western diet one week after being exposed to a stress test, when compared with control subjects. However, when it came time to look at changes in the size of brain structures using MRI, the team found “significant hippocampal atrophy” and “lateral ventricular enlargement” in subjects that ate the high-fat diet. “We found a 20 decrease in the size of their hippocampi and a 50 percent increase in the size of the lateral ventricles,” Figueroa said. He adds that a reduction in size of the hippocampi, which there are two of them, one on either side of the brain, is associated with a loss in memory and cognitive function, and that an increase in the size of the lateral ventricles is similarly related to brain dysfunction and disorders such as schizophrenia, bipolar disorder, depression and Alzheimer’s disease. Figueroa and his team found that eating a high-fat diet during adolescence leads not only to obesity, but more importantly, to a reduction in the brain’s ability to recover from stressful events. Stated more forcefully, adolescent obesity has now been proven to affect mental health during adulthood, particularly during incidence of stress. “We anticipate that this study will inform the path to needed biomarkers and interventions for improving the quality of stress and anxiety management, particularly in a growing overweight and obese population,” he concludes.