Serum carotenoid levels inversely correlate with depressive symptoms among adults: Insights from NHANES data

Background: Carotenoids are a group of tetraterpenoid lipophilic pigments linked to depression, but studies on individual carotenoid components are lacking. We aimed to assess the association between each serum carotenoids and depressive symptoms in adults. Methods: This cross-sectional study included 7264 adults from the National Health and Nutrition Examination Survey (NHANES). Serum carotenoid levels (a-carotene, (3-carotene, (3-cryptoxanthin, lycopene, and lutein/ zeaxanthin) were measured using high-performance liquid chromatography. Participants with a Patient Health Questionnaire score >= 10 were considered to have depressive symptoms. The association between each carotenoid and depressive symptoms was investigated using multivariable-adjusted logistic regression, restricted cubic spline, and weighted quantile sum regression models. Results: The participants' average age was 46.0 (interquartile range: 34.0-60.0) years (50.9 % females), and 545 participants (7.5 %) were diagnosed with depressive symptoms. The logistic regression model demonstrated that high serum a-carotene, (3-carotene, (3-cryptoxanthin, and lutein/zeaxanthin levels were associated with a lower likelihood of depressive symptoms. The restricted cubic spline model revealed that the significantly inverse relationships between serum carotenoid levels and the risk of depressive symptoms were nonlinear for a-carotene, (3-carotene, (3-cryptoxanthin, and lutein/zeaxanthin and were linear for lycopene. The threshold effect analysis further identified the inflection points were 12.1, 35.7, 5.9, and 7.7 mu g/dL for a-carotene, (3-carotene, (3-cryptoxanthin, and lutein/zeaxanthin, respectively. The weighted quantile sum regression model revealed that (3-cryptoxanthin (35.2 %) and a-carotene (34.5 %) were the top-weighted carotenoids correlated with depressive symptoms. Conclusions: The present results suggested an association between higher levels of each serum carotenoids and a decreased risk of depressive symptoms in adults.