Fish consumption increases vitamin D levels by 4.08 nmol/L in children across randomized trialsEating fish may help improve vitamin D levels in growing children

Frontiers in Medicine Published June 9, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Note that fish consumption modestly improves vitamin D levels in children, though clinical relevance is uncertain.

This meta-analysis synthesized data from randomized controlled trials to evaluate how fish consumption affects various micronutrient statuses in children aged 2 to 14 years. The analysis included a primary sample size of 1,074 participants and a sensitivity analysis involving 850 participants.

The primary finding was a pooled mean difference of 4.08 nmol/L favoring fish consumption for vitamin D (25(OH)D) with a 95% CI of 1.73 to 6.43. A sensitivity analysis yielded a slightly lower increase of 3.46 nmol/L (95% CI: 1.03 to 5.65). Other biomarkers, including urinary iodine, ferritin, hemoglobin, retinol, beta-carotene, calcium, cobalamin, and folate, were largely nonsignificant.

The authors noted several limitations, including inconsistent evidence for most micronutrients and the possibility that the observed increase in vitamin D levels may lack clinical relevance. While the randomized trial design allows for causal inference regarding fish consumption and vitamin D status, the magnitude of improvement is modest. Clinical application should consider whether these specific increases translate to meaningful health outcomes for children.

A large review of clinical studies looked at how eating fish affects the health of children between ages 2 and 14. The study focused on several important nutrients, including vitamin D, iodine, and iron.

The results showed that children who ate fish had higher levels of vitamin D compared to those who did not eat much fish. While the increase was steady, it was a modest change in the overall amount of vitamin D found in their systems.

Other nutrients like calcium, iodine, and folate did not show significant changes based on fish intake alone. The researchers noted that while the link to vitamin D is clear, the actual amount of improvement might be small enough that it does not change daily health much.

Overall, including fish in a child's diet is a reliable way to support their vitamin D levels. However, other nutrients may need to come from different sources to ensure children get everything they need for healthy development.

What this means for you:

Children who eat fish have higher vitamin D levels, though the increase is modest and consistent.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJun 2026

View Original Abstract ↓

IntroductionFish 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.MethodsThree 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.ResultsSeven 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.ConclusionFish 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.

Fish consumption increases vitamin D levels by 4.08 nmol/L in children across randomized trialsEating fish may help improve vitamin D levels in growing children

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Fish consumption increases vitamin D levels by 4.08 nmol/L in children across randomized trialsEating fish may help improve vitamin D levels in growing children

Study Details

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