Location: Obesity and Metabolism ResearchTitle: Breakfast skippers display a disrupted cortisol rhythm and elevated blood pressure
|WHITBRACHT, MEGAN - UNIVERSITY OF CALIFORNIA|
|FORESTER, SHAVAWN - UNIVERSITY OF CALIFORNIA|
|WIDAMAN, ADRIANNE - UNIVERSITY OF CALIFORNIA|
Submitted to: Physiology and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2014
Publication Date: 12/30/2015
Citation: Whitbracht, M.G., Keim, N.L., Forester, S., Widaman, A., Laugero, K.D. 2015. Breakfast skippers display a disrupted cortisol rhythm and elevated blood pressure. Physiology and Behavior. 140:215-221. doi:10.1016/j.physbeh.2014.12.044.
Interpretive Summary: Breakfast skipping is prevalent in the U.S.. Habitual breakfast skipping may be detrimental to health and has been linked to elevated blood pressure, insulin resistance, and dyslipidemia. However, a physiological basis connecting regular breakfast skipping and poor metabolic health is unclear. In this study, we compared basal and stimulated cortisol concentrations at home and in the laboratory between women who habitually eat or skip breakfast. We also assessed cardiometabolic disease risk factors in these women. Our results showed marked elevations of both basal and meal stimulated cortisol concentrations in women who regularly skip breakfast more than 4 times a week. Breakfast skipping was also associated with a blunted diurnal cortisol profile and elevated blood pressure. Our results suggest that habitual breakfast skipping may disrupt cortisol rhythms and responsivity, which may explain higher blood pressure and other previously described cardiometabolic dysfunction in persons habitually skipping breakfast.
Technical Abstract: Chronic stress and over-activity in the hypothalamic-pituitary-adrenal (HPA) axis may link breakfast skipping and poor cardiometabolic health. Missing the first major meal of the day in rodents prolongs elevated circulating corticosterone at a time when it’s normally decreasing. To extend these findings to humans, we hypothesized that habitual breakfast skippers would display a similar pattern of circulating cortisol and alterations in meal and stress-induced cortisol reactions. Normal weight to obese women aged 18-45 years old who were strictly defined as either breakfast skippers (n = 30) or breakfast eaters (n = 35) were invited to participate in our study. Normal breakfast habits were maintained for the entire study period and each participant attended 4 lab visits. Over the first 2 lab visits, body composition, fasting clinical chemistries, and self-reports of chronic stress were assessed. On each of 2 additional days (lab visits 3 and 4), salivary free cortisol was measured at home upon waking and at bedtime, and in the lab in response to a standard lunch, ad libitum afternoon snack buffet, and stress and control (relaxation) tasks. The order of the control and stress test visits was randomized. While body weight, body composition, HOMA-IR, total and HDL cholesterol did not statistically differ (p>0.05), both diastolic and systolic blood pressure were elevated (p<0.01) and LDL cholesterol was lower (p=0.04) in the breakfast skipper group. Compared to the breakfast eaters and on the control task visit only, breakfast skippers had higher circulating cortisol from arrival to midafternoon (p<0.01) and during the snack buffet (p<0.05). Furthermore, the lunch-induced cortisol reaction was larger in the ‘skippers’ (p=0.03). On both stress and control visit days, the diurnal cortisol amplitude was significantly (p=0.02) blunted in breakfast skippers. Self-reports of chronic stress did not differ between the groups. These data indicate that habitually skipping breakfast is associated with stress-independent over-activity in the HPA axis which, if prolonged, may increase risk (e.g., hypertension) for cardiometabolic disease in some people.