Pro-vegetarian dietary patterns and essential and heavy metal exposure in children of 4-5-years from the INfancia y medio Ambiente cohort (INMA)

Dietary patterns provide a comprehensive assessment of food consumption, including essential nutrients and potential exposure to environmental contaminants. While pro-vegetarian (PVG) dietary patterns have shown health benefits in adults, their effects on children are less well studied. This study aims to explore the association between children's adherence to the most common PVG dietary patterns and their exposure to metals, assessed through urine concentration. In our study, we included a population of 723 children aged 4-5-years from the INfancia y Medio Ambiente (INMA) cohort in Spain. We calculated three predefined PVG dietary patterns, namely general (gPVG), healthful (hPVG), and unhealthful (uPVG), using dietary information collected through a validated Food Frequency Questionnaire. Urinary concentrations of various essential and heavy metals (Co, Cu, Zn, Se, Mo, Pb, and Cd) were measured using mass spectrometry. Additionally, urinary arsenic speciation, including arsenobetaine (AsB), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and inorganic arsenic (iAs), was measured. The sum of urinary MMA and iAs was used to assess iAs exposure. We estimated primary (PMI) and secondary iAs methylation (SMI) indices. To explore the association between PVG dietary patterns in quintiles and metal exposure, we utilized multiple-adjusted linear regression models and the quantile g-computation approach. Compared with the lowest quintile, participants in the highest quintile of gPVG showed a 22.7% lower urinary Co (95% confidence interval (CI): -38.7; -1.98) and a 12.6% lower Se (95%CI: -22.9; -1.00) concentrations. Second quintile of adherence to hPVG was associated with a 51.7% lower urinary iAs + MMA concentrations (95%CI: -74.3; -8.61). Second quintile of adherence to an uPVG was associated with a 13.6% lower Se levels (95%CI: -22.9; -2.95) while the third quintile to this pattern was associated with 17.5% lower Mo concentrations (95%CI: -29.5; -2.95). The fourth quintile of adherence to gPVG was associated with a 68.5% higher PMI and a 53.7% lower SMI. Our study showed that adherence to a gPVG dietary pattern in childhood may modestly reduce the intakes of some essential metals such as Co and Se. Further investigations are warranted to explore any potential health implications.

Association between mediterranean diet and metal(loid) exposure in 4-5-year-old children living in Spain

Even relatively low levels of metals exposure may impact health, particularly among vulnerable populations such as infants and young children. However, little is known about the interplay between simultaneous metal exposures, common in real-life scenarios, and their association with specific dietary patterns. In this study, we have evaluated the association between adherence to Mediterranean diet (MD) and urinary metal concentrations individually and as an exposure mixture in 713 children aged 4-5-years from the INMA cohort study. We used a validated food frequency questionnaire to calculate two MD indexes scores: aMED and rMED. These indexes gather information on various food groups within the MD and score differently. To measure urinary concentrations of cobalt, copper, zinc, molybdenum, selenium, lead, and cadmium as exposure biomarkers, we used inductively coupled plasma mass spectrometry (ICP-MS), coupled with an ion chromatography (IC) equipment for arsenic speciation analysis. We applied linear regression and quantile g-computation, adjusted for confounders, to analyse the association between MD adherence and exposure to the metal mixture. High adherence to MD such as the quintile (Q) 5 MD was associated with higher urinary arsenobetaine (AsB) levels than Q1, with β values of 0.55 (confidence interval - CI 95% 0.01; 1.09) for aMED and 0.73 (CI 95% 0.13; 1.33) for rMED. Consumption of fish was associated with increased urinary AsB but reduced inorganic arsenic concentrations. In contrast, the aMED vegetables consumption increased urinary inorganic arsenic content. A moderate level of adherence to MD (Q2 and Q3) was associated with lower copper urinary concentrations than Q1, with β values of -0.42 (CI 95% -0.72; -0.11) for Q2 and -0.33 (CI 95% -0.63; -0.02) for Q3, but only with aMED. Our study, conducted in Spain, revealed that adhering to the MD reduces exposure to certain metals while increasing exposure to others. Specifically, we observed increase in exposure to non-toxic AsB, highlighting the significance of consuming fish/seafood. However, it is crucial to emphasize the necessity for additional efforts in reducing early-life exposure to toxic metals, even when adhering to certain food components of the MD.