UC Davis

It is widely recognized that dietary intake can influence stress and stress-related health outcomes. Appreciating differences in age, sex and gender, genetic, physiological, metabolic, cognitive, and microbial contexts and interactions are several critical factors to consider when determining the effects of diet on stress and stress-associated health outcomes. A primary aim of this work is to increase awareness of the need and importance for precise, developmental stage-specific nutrition strategies to prevent or mitigate stress-related disease throughout the lifespan.

Three studies were developed to investigate the interrelationships between food intake, stress, and stress-related health outcomes in humans of varying stages of development. One study was designed to target the infant gut microbiome through a specific dietary component. The study evaluated the effects of feeding the human gut symbiont B. infantis EVC001 on diaper rash in infants, crying/fussiness, and naptime and nighttime sleep behavior. Results showed reductions in all three outcome variables, which are indicators of perceived and physiologic neonatal stress. Another study aimed to assess the ability of a wearable nutritional-tracking device to capture individualized dietary intake information, and metabolic responses to food, in adults. Repeated engagements in “fad” diets can increase risk for physiological stress in the body; thus, advances in wearable technology have potential to empower users to achieve and maintain personalized lifestyle behaviors, body composition, and health, rather than relying on misinformed nutritional information. Study results highlight the need for technologies that can reliably measure diet to improve nutrition-based guidance and facilitate precision-based nutrition interventions. Finally, a study was designed to examine sex-dependent associations between allostatic load, that is a biomarker of physiological stress load, and diet quality in the form of the Healthy Eating Index in adults. Results showed that sex and diet quality pattern interacted to affect allostatic load, and a significantly different allostatic load for men and women consuming a diet pattern more closely aligned with the Dietary Guidelines for Americans for dairy, refined grains, and sodium consumption, but less aligned for added sugar, saturated fat, and fruit/vegetable intake.

Cumulatively, the results of this dissertation highlight the need for methods to accurately assess stress, diet, and health, in real-time and under free-living conditions. This research has the potential to inform precise nutrition interventions to mitigate stress-related disease risk in humans at differing life stages.