Serum Carotenoids and Cancer-Related Fatigue: An Analysis of the 2005–2006 National Health and Nutrition Examination Survey

Cancer-related fatigue is a prevalent, debilitating condition, and preliminary evidence suggests a relationship between higher diet quality and lower fatigue. Serum-based carotenoids, Vitamin A, and Vitamin E are biomarkers of fruit and vegetable intake and therefore diet quality. To further elucidate the link between diet quality and cancer-related fatigue, associations were assessed between these serum-based nutrients and fatigue among American adults with special attention to cancer history. Data were analyzed from the United States 2005–2006 National Health and Nutrition Examination Survey dataset. Ten carotenoids, vitamin A, vitamin E, and γ-tocopherol were measured from fasting blood samples and fatigue was patient-reported. Associations between carotenoid concentration and fatigue were estimated using ordinal logistic regression models. Adjusted models included a diagnosis of cancer (with the exception on nonmelanoma skin cancer, yes/no), age, body mass index, race/ethnicity, education, and exercise habits as covariates, and additional models included a cancer × nutrient interaction. Of 4,091 participants, 272 (8.0%) reported a history of cancer. Greater fatigue was associated with lower serum trans-lycopene, retinyl palmitate, and retinyl stearate (all P < 0.05) in separate models adjusting for potential confounders. For these nutrients, a one-SD increase in nutrient was associated with a 6.8%–9.9% lower risk of greater fatigue. Among cancer survivors only (n = 272), statistically significant associations were not observed between any of the nutrients and fatigue. In conclusion, greater serum concentrations of carotenoid biomarkers were associated with less fatigue. These results support further exploration into relationships between carotenoid intake, diet quality, and persistent fatigue. Significance: Cancer-related fatigue often persists for years into survivorship, reduces quality of life, and prevents people from returning to their lives before cancer. Interventions to address cancer-related fatigue are much needed. Herein, serum carotenoids were associated with lower fatigue, thereby supporting further development of nutritional interventions to address fatigue in survivorship.