The effect of an organic food intervention treatment on biomarkers of exposure to lead and cadmium in primary school children of Cyprus: A cluster-randomized crossover trial

Background: Food contaminants, such as, pesticides and metals are ubiquitous in the food chain. Studies routinely report on the metals content of organic and conventional food crops. However, comparative human studies on the body burden of metals associated with organic food consumption are currently lacking.

Objectives: The objectives were to i) determine the effectiveness of an organic food intervention in reducing the body burden of urinary concentration of lead (Pb) and cadmium (Cd) and ii) evaluate the association between metal exposures and biomarkers of oxidative damage in primary school children in Cyprus.

Methods: This study was part of the ORGANIKO cluster-randomized crossover trial, a 40-day organic food treatment to 149 healthy children (10-12 years) in Cyprus. Urinary biomarkers of Pb and Cd were determined using inductively coupled plasma mass spectrometry. Linear mixed-effect regression models were used to account for the effect and duration of the organic food treatment. Multiple comparisons were handled using Benjamini-Hochberg correction.

Results: A time-dependent reduction for creatinine-adjusted Pb during the intervention period was observed (β = -0.021; 95% CI: -0.034, -0.008; p-adjusted = 0.01). A similar trend was observed for creatinine-adjusted Cd, but it was not significant (β = -0.013; 95% CI: -0.026, 0.000; p-adjusted = 0.15). The creatinine-adjusted oxidative damage biomarkers were significantly associated with both metal biomarkers; Pb (8-OHdG: β = 0.388, 95% CI: 0.303, 0.472; p-adjusted<0.001; MDA: β = 0.187, 95% CI: 0.109, 0.265; p-adjusted<0.001; 8-iso-PGF2a: β = 0.320, 95% CI: 0.244, 0.397; p-adjusted<0.001), and Cd (8-OHdG: β = 0.148, 95% CI: 0.063, 0.233; p-adjusted = 0.003; MDA: β = 0.107, 95% CI: 0.030, 0.184; p-adjusted = 0.018; 8-iso-PGF2a: β = 0.263, 95% CI: 0.186, 0.339; p-adjusted<0.001).

Discussion: A 40-day organic food treatment reduced primary school children's exposures to Pb over time. More human studies in settings with high food contaminant profiles across common crops are warranted.