Association between diet-derived antioxidants and asthma: Insights from the NHANES survey 2003–2018 and Mendelian randomization analysis

Background

Many studies have reported correlations between diet-derived antioxidants and asthma. Nevertheless, the probable association between diet-derived antioxidants and asthma remains a matter of discussion.

Objectives

We explored the association between Diet-Derived Antioxidants and Asthma.

Methods

We used data from the 2003–2018 National Health and Nutrition Examination Survey (NHANES) to assess the relationship between diet-derived antioxidants and asthma and a two-sample Mendelian randomization (MR) study was employed to assess the causal associations between lifelong diet-derived circulating antioxidant levels and the risk of asthma.

Results

Participants with asthma were more likely to be young-to-middle-aged females, smokers, have lower income, belong to non-Hispanic Black ethnicity, have a high school education, have a BMI over 30. The dietary intakes of vitamin C, zinc, selenium, and CDAI were negatively associated with asthma risk (Vitamin C: OR = 0.76, 95 % CI: 0.63–0.91, P = 0.032; Zinc: OR = 0.86, 95 % CI: 0.75–1.00, P = 0.046; Selenium: OR = 0.85, 95 % CI: 0.73–0.98, P = 0.004; CDAI: OR = 0.80, 95 % CI: 0.65–0.97, P = 0.027). There was a significant nonlinear relationship between the dietary intake of vitamin C, zinc, and selenium and the risk of asthma (P_non-linear < 0.05). However, no causal link between circulating antioxidants and asthma risk was found in the MR analysis. Sensitivity analyses supported the robustness of the results.

Conclusion

In the observational study, we identified a negative correlation between the dietary intake of vitamin C, zinc, selenium, and CDAI and asthma risk, while our MR analyses did not find evidence to support a causal relationship between diet-derived antioxidants and the risk of asthma.