Stress and Diet Interact to Influence Health
Many Americans consume foods that are energy-dense, but nutrient-poor. Moreover, we tend to consume a high number of calories without an equivalent amount of calorie-burning physical activity, which could partially explain the prevalence of obesity and its associated diseases. Psychological or emotional stress is also linked to poor diet and associated chronic diseases of the brain and body. For these reasons, ARS researchers are studying the possible links between human stress, dietary habits, and health.
Kevin Laugero, a nutritionist from the Western Human Nutrition Research Center in Davis, CA, explains that stress can influence what we eat. In turn, he notes there is a growing body of evidence showing that our dietary habits can shape the way our brain and body respond to life stressors. In fact, Laugero notes that nutritional habits may at least partly explain why some people are more or less resilient to stress and stress-related disease risk.
Stress triggers physiological responses in the brain and body that can profoundly alter our behavior and metabolism, Laugero explains. These responses help us deal with and adapt to life’s periodic challenges. However, when the levels of stress and stress reactions in the body do not return to normal and instead become prolonged (chronic stress) or inappropriate for a given situation, these stress-induced physiological responses can lead to detrimental changes in the body and brain.
Furthermore, he notes that it’s not just the overexaggerated stress reactions that are linked to poor health, but that abnormally low reactions to stress might be equally detrimental to one’s health. Understanding the biological reasons for why people respond differently to the same stressors may partially explain person-to-person differences in stress vulnerability and disease risk. Laugero’s research team is investigating whether certain dietary patterns, individual foods, or nutrients provide insight into this clinically relevant question.
Laugero also explains another way that stress might sabotage health. He notes that individual differences in stress responsiveness or levels of stress-related hormones, such as cortisol, may limit the body’s or brain’s ability to respond to a healthy diet. In addition to promoting poor dietary choices and dampening motivation to exercise, “elevation in stress-response hormones, such as cortisol, can lead to insulin resistance, hyperglycemia, increases in blood pressure, increases in cholesterol, and hypertriglyceridemia.” Laugero says. “Therefore, differences in the status or biological activity of these hormones in the body might be expected to alter how a person’s body responds to a healthy diet.”
Laugero and his collaborators recently found in a nutrition intervention study that having higher concentrations of circulating cortisol, before being placed on a Dietary Guidelines for Americans (DGA)-based diet, limited the diet’s cholesterol-lowering effect (compared to those with lower pre-intervention circulating cortisol). Therefore, person-to-person differences in cortisol may influence how the body responds to certain dietary patterns. This research finding was published in Current Developments in Nutrition.
Laugero and his collaborators currently apply an interdisciplinary approach to directly test in human nutrition intervention studies the health impact of the DGA. Results from this ongoing effort are expected to have immediate nutrition policy implications and help identify modifiable factors, including stress, that influence how people respond to dietary patterns. By Olga Vicente, ARS’s Office of Communications
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