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Research Project: Improving Public Health by Understanding Metabolic and Bio-Behavioral Effects of Following Recommendations in the Dietary Guidelines for Americans

Location: Obesity and Metabolism Research

Title: Waking salivary cortisol associated with magnitude of cholesterol reduction in women fed a healthy whole-food diet for 8 weeks

item SOLTANI, HODA - University Of California, Davis
item Keim, Nancy
item Laugero, Kevin

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2022
Publication Date: 5/3/2022
Citation: Soltani, H., Keim, N.L., Laugero, K.D. 2022. Waking salivary cortisol associated with magnitude of cholesterol reduction in women fed a healthy whole-food diet for 8 weeks. Current Developments in Nutrition. 6(5). Article nzac083.

Interpretive Summary: Psychological stress is associated with elevated risk for hypertension, cardiovascular disease, gastrointestinal disorders, type 2 diabetes, and neurological conditions. On the other hand, improvements in nutrition can prevent or even reverse these chronic health problems. It is not known whether underlying stress can mitigate the health promoting effects of consuming a healthy diet. A randomized, double-blind, controlled 8-week diet intervention was conducted in overweight and obese women to assess whether underlying stress prior to the intervention modified the comparative effects of a diet based on the Dietary Guidelines for Americans (DGA) and a typical American diet (TAD). Results from this study showed that, compared to the TAD, the DGA based diet reduced total and low-density lipoprotein (LDL) cholesterol, but this potentially beneficial effect of the DGA was inhibited in participants who also had high levels of a key stress hormone, cortisol, in the morning upon wakening. In support of this finding, participants assigned to the DGA diet intervention showed an association between higher morning cortisol and greater 8-week increases in circulating total cholesterol. In conclusion, these findings suggest that the cholesterol lowering effect of a DGA diet is sensitive to variations in morning cortisol status, and imply that stress or other factors that significantly elevate waking cortisol may limit some effects of whole food diets to reduce cardiovascular disease risk.

Technical Abstract: Context. Stress and poor diet are independently linked to cardiometabolic disease risk, but underlying stress and stress mediators may influence cardiometabolic effects of diet. Objective. This study examined whether baseline behavioral and physiological markers of stress interacted with 8-week diet interventions (DI) to affect cardiometabolic outcomes. Design. A randomized, double-blind, controlled 8-week diet intervention was conducted. Setting. The trial was conducted at the Western Human Nutrition Research Center in Davis, CA. Patients or Other Participants. Participants were overweight or obese women 20–64 years old, minimally active, and insulin resistant and/or dyslipidemic. Intervention. Diets were randomly assigned and based on the 2010 Dietary Guidelines for Americans (DGA) or a typical American diet (TAD). Cardiometabolic risk factors and stress indicators were assessed at baseline and 8 weeks. Main Outcome Measures. Factor analysis was applied to baseline and 8-wk cardiometabolic outcome variables to derive fourteen individual 8-wk delta factor scores. Results. Baseline waking cortisol concentrations interacted (P=0.0474) with DI to affect a factor characterized by 8-wk increases in LDL and total cholesterol. Compared to TAD, DGA associated with 8-wk decreases in LDL and total cholesterol in participants with low (10th percentile; 2.76 nmol/L) or average (7.76 nmol/L), but not higher (90th percentile; 13.44 nmol/L) baseline waking cortisol. Consistent with this finding, there was a DGA-specific positive association (P=0.0047; ': 2.88 ± 0.94) between baseline waking cortisol and 8-wk increases in total cholesterol. Conclusions. Underlying status of waking cortisol may explain inter-individual variability in cardiometabolic responses to whole food diets.