Systematic review and meta-analysis of randomized controlled trials assessing the impact of fish consumption on micronutrient status of children

Introduction Fish consumption contributes to overall nutrient intake and health, but its effects on micronutrient status remain uncertain. We conducted a systematic review and meta-analysis to assess the impact of fish consumption on the micronutrient status of children. Methods Three databases were searched (April 2025) for studies comparing biomarker-based micronutrient status among children (2–14 years) with fish versus low or no fish intake. Risk of bias was assessed using RoB2, and findings were synthesized through meta- and narrative analyses with GRADE evaluation. Results Seven studies (six randomized controlled trials) met inclusion criteria, covering nine biomarkers, including 25(OH)D, urinary iodine concentration, ferritin, hemoglobin, retinol, beta-carotene, calcium, cobalamin, and folate. Three studies had low risk of bias, two moderate, and one high. Meta-analysis was possible only for vitamin D (25(OH)D, 1,074 participants), showing a pooled mean difference of 4.08 nmol/L (95% CI: 1.73–6.43) favoring fish consumption; sensitivity analysis (850 participants) yielded 3.46 nmol/L (95% CI: 1.03–5.65), with no heterogeneity. Results for other biomarkers were largely nonsignificant. Conclusion Fish consumption modestly improves vitamin D status in children, though effects may lack clinical relevance. Evidence for other micronutrients is inconsistent, highlighting the need for more rigorous studies.