Advanced Fellow at the VA Veteran Affairs Baltimore, Maryland, United States
Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.
Disclosure(s):
Galya Bigman, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Some studies have shown that flavonoids, a group of natural compounds found in plant foods, have an effect on mental health. Yet, more research is needed to establish their role in depression.
Objective: To examine the association between flavonoid intake and depression in a representative national sample of U.S. adults.
Hypothesis: High flavonoid intake is inversely associated with depressive symptoms.
Methods: Sample: A population-based cross-sectional study utilizing data from the National Health and Nutrition Examination Survey (NHANES: 2007–2010, 2017–2018).
Outcome: Self-reported depressive symptoms were assessed by the 9-item Patient Health Questionnaire (PHQ-9). PHQ-9 total score was analyzed as a continuous variable (range: 0-27).
Exposure: Based on two 24-hour recalls, flavonoids' main food sources werecocoa/chocolate, tea, soy-based products, onions, chili/sweet peppers, berries, dark-green leafy vegetables, celery, and lemon. Total flavonoid intake (mg/day) was calculated and divided into quartiles (Q1-Q4)..
Covariates: Age, sex, race/ethnicity, income-to-poverty ratio, education, BMI, Healthy Eating Index (HEI-2015), physical activity, alcohol use, smoking status, and history of comorbidities e.g., diabetes, stroke, cancer, and cardiovascular diseases.
Statistical Analysis: Due to the positive skewness and excess of zeros (33.3%) in the PHQ-9 total score, a weighted negative binomial regression model was employed to examine the target hypothesis.
Results: The final sample included N=12,715 eligible participants with means (±SD) age of 47.7±17 years. Median [interquartile range (IQR)] for PHQ-9 was: 2[0-4] and for flavonoid intake (mg/day) by its quartiles: Q1:12[10], Q2:40[20], Q3:108[70], and Q4:484[457]. After adjusting for covariates, the multivariable model showed a significant inverse association between flavonoid and depression. Participants in the highest vs. lowest quartiles of flavonoid intake had by 10-13% lower incident rate of depressive symptoms (incidence rate ratio [IRR]Q4vs.Q1=0.87, 95%CI: 0.80–0.94; IRRQ3vs.Q1=0.87, 95%CI: 0.79–0.96); IRRQ2vs.Q1=0.90, 95%CI: 0.83–0.98).
Conclusions: Flavonoids may have a central role in alleviating or preventing depressive symptoms. Further research is needed to elucidate the mechanisms of this imperative link.
