Association between optimism and serum antioxidants in the midlife in the United States study

Psychological and physical health are often conceptualized as the absence of disease; there is less research that addresses positive psychological and physical functioning. For example, optimism has been linked with reduced disease risk and biological dysfunction, but very little research has evaluated associations with markers of healthy biological functioning. Thus, we investigated the association between two indicators of positive health: optimism and serum antioxidants.

The cross-sectional association between optimism and antioxidant concentrations was evaluated in 982 men and women from the Midlife in the United States study. Primary measures included self-reported optimism (assessed with the revised Life Orientation Test) and serum concentrations of nine different antioxidants (carotenoids and vitamin E). Regression analyses evaluated the relationship between optimism and antioxidant concentrations in models adjusted for demographics, health status, and health behaviors.

For every standard deviation increase in optimism, carotenoid concentrations increased by 3% to 13% in age-adjusted models. Controlling for demographic characteristics and health status attenuated this association. Fruit and vegetable consumption and smoking status were identified as potential pathways underlying the association between optimism and serum carotenoids. Optimism was not significantly associated with vitamin E.

Optimism was associated with greater carotenoid concentrations, and this association was partially explained by diet and smoking status. The direction of effects cannot be conclusively determined. Effects may be bidirectional given that optimists are likely to engage in health behaviors associated with more serum antioxidants, and more serum antioxidants are likely associated with better physical health that enhances optimism.