Metal exposures and their interactions with the dietary inflammatory index on inflammatory biomarkers in Mexican...

Heavy metals, like lead, arsenic, and cadmium, are linked to increased inflammation even in early life; however, anti-inflammatory diets may offset these effects.

We evaluated associations between heavy metals and inflammatory biomarkers, and potential effect modification by diet in 399 adolescents aged 10 to 18 at baseline who attended two study visits 2 years apart (773 observations). At baseline, blood lead, urinary arsenic, and cadmium concentrations were measured, and the Children's Dietary Inflammatory Index (C-DII) was calculated. Fasting serum interleukin (IL)-4, IL-10, IL-1β, IL-6, IL-8, high-sensitivity C-reactive protein, and tumor necrosis factor-alpha were measured for both visits. Generalized estimating equation models were fit to assess associations between metal concentrations and repeatedly measured inflammatory biomarkers, adjusting for study visit and baseline sociodemographic and lifestyle variables. Effect modification by diet was assessed by including metal and C-DII tertiles interaction terms.

At baseline, the median age was 13.6 years, 50.4% were females, and 51.1% had a low socioeconomic status. Overall, there were no associations between metals and inflammatory markers in the entire population. In the most anti-inflammatory diet group (C-DII T1), higher blood lead was associated with higher IL-4, IL-1β, IL-6, and IL-8 levels, whereas for the most pro-inflammatory diet (C-DII T3), these associations were inverse (P-trend <0.05). Contrarily, higher urinary arsenic was associated with lower IL-4, IL-6, and IL-8 levels in the anti-inflammatory diet group and positively associated with these cytokines in the pro-inflammatory diet group (P-trend <0.05).

Anti-inflammatory diets may modify adolescents' inflammatory response to lead and arsenic. Heavy metal toxicity mitigation by anti-inflammatory diets requires further research.