Evaluation of an Organic Diet Intervention to Reduce Pesticide Exposure: A Repeated Measures Cross-Over Study Among Rural and Urban Communities in Selangor, Malaysia

Introduction. Organophosphate (OP) pesticides are widely used in agriculture, resulting in dietary pesticide exposure through conventionally grown foods. While organic diets are often recommended to reduce pesticide burden, the effectiveness of such interventions and the influence of local environmental factors and metabolic differences remain underexplored in mixed urban–rural settings.

This study investigated the impact of a short-term organic diet intervention on urinary OP metabolite concentrations among rural and urban adults and children in Selangor, Malaysia, and assessed the rebound effect after returning to a conventional diet. Method. Seventeen families (9 rural, 8 urban) participated in a 16-day cross-over intervention, consisting of a baseline conventional diet phase (4 days), an organic diet phase (7 days), and a post-intervention conventional diet phase (5 days).

Daily first-morning void urine samples were analyzed for four OP metabolites (DMP, DEP, DMTP, DETP). Linear mixed-effects models assessed differences across dietary phases, and daily trends illustrated changes over time. Result. Urinary concentrations of DMP, DEP, and DMTP declined significantly during the organic diet phase compared to baseline (p < 0.05), with the largest reductions observed in children. DETP levels remained relatively stable across phases.