Behaviour 2019
Effects of Mediterranean vs. Western Diets on Affiliation, Activity, and Anxiety in Nonhuman Primates
Corbin S.C. Johnson1, Brett M. Frye2, Timothy D. Howard2, Thomas C. Register2, Noah Snyder-Mackler1,3, Carol A. Shively2. 1University of Washington, Seattle, WA, United States; 2Wake Forest School of Medicine, Winston-Salem, NC, United States; 3Arizona State University, Tempe, AZ,

What an animal eats impacts its health and survival, although little is known about mediating factors that may be involved. Anxiety-like behaviors and social isolation increase disease risk, and recent evidence from monkeys and rodents suggests that diet composition may affect health in part through effects on behavior. Here, we examined the effects of Western- (WEST) and Mediterranean-like (MED) diets on social behavior in a randomized, pre-clinical, 24-month trial of middle-aged female monkeys (Macaca fascicularis). Behavior was recorded twice a week in 10-min focal observations. MED increased body contact by 235% in the first month (p = 0.005) and averaged 569% of baseline throughout (p = 5.0 x 10-8). MED also altered activity (e.g. 46% decrease in locomotion in first month, p = 0.006; 54% of baseline throughout, p = 3.1 x 10-5) and anxiety-like behaviors (21% decrease in first month, p = 0.03; 69% of baseline throughout, p = 9.3 x 10-5). Some effects of diet were context dependent: e.g. WEST increased locomotion in socially dominant animals only (p = 4.1 x 10-10). Thus, diet-induced behavioral changes may mediate the physical phenotypes and pathologies associated with diet.