Overview
Childhood overweight and obesity are rising global concerns linked to a cluster of cardiometabolic risk factors, including insulin resistance, dyslipidemia, high blood pressure, and inflammation. Vitamin D has been proposed as a potential modulator of metabolic health due to its roles in inflammation, insulin secretion, and lipid metabolism. This article summarizes a grade-assessed systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluated the impact of vitamin D supplementation on cardiometabolic outcomes in children and adolescents with overweight or obesity.
Why investigate vitamin D in this population?
Vitamin D deficiency is common among youth with excess weight, potentially due to sequestration of the vitamin in adipose tissue and limited sun exposure. Observational studies have yielded inconsistent links between vitamin D status and cardiometabolic risk, prompting the need for randomized evidence. If vitamin D positively affects risk factors, supplementation could be a simple, low-cost strategy to improve long-term cardiovascular health in a high-risk pediatric group.
What the meta-analysis examined
The review pooled data from randomized controlled trials that allocated overweight or obese children and adolescents to vitamin D supplementation versus placebo or no treatment. Eligible trials measured cardiometabolic factors such as fasting glucose, insulin resistance (e.g., HOMA-IR), lipid profiles (total cholesterol, LDL, HDL, triglycerides), blood pressure, inflammatory markers, and markers of vascular function. The analysis aimed to determine whether supplementation provides clinically meaningful changes beyond changes attributable to weight management or lifestyle interventions.
Key findings
Across included studies, vitamin D supplementation produced modest improvements in some cardiometabolic markers in select subgroups, but results were not uniform across all outcomes. Several trials noted favorable shifts in insulin resistance indices and triglyceride levels, particularly when baseline vitamin D deficiency was present or when higher, sustained dosing achieved adequate serum 25(OH)D levels. However, other cardiometabolic endpoints—such as LDL cholesterol, HDL cholesterol, and systolic/diastolic blood pressure—showed little to no consistent benefit.
These mixed results highlight several important considerations: the heterogeneity of study designs (dose, duration, baseline vitamin D status), differences in obesity severity, and concurrent lifestyle modifications that can confound outcomes. The conclusions emphasize that while vitamin D may help in specific contexts (e.g., deficient individuals), it should not replace established interventions like diet modification, physical activity, and weight management programs.
Clinical implications
For clinicians, the evidence suggests a nuanced approach to vitamin D in overweight and obese youth. Routine supplementation solely for improving cardiometabolic risk factors is not universally supported by RCT data. Instead, a targeted strategy—testing for deficiency, correcting insufficiency, and integrating vitamin D with comprehensive lifestyle interventions—appears more prudent. Monitoring serum 25(OH)D levels can guide dosing to reach sufficiency without oversupplementation. In pediatric endocrinology and pediatrics more broadly, decisions should consider the child’s overall metabolic profile, comorbid conditions, and growth requirements.
Research gaps and future directions
The meta-analysis underscores the need for high-quality, adequately powered RCTs with standardized outcomes and longer follow-up. Future studies should stratify by baseline vitamin D status, obesity severity, age, puberty stage, and concurrent nutritional and physical activity programs. Investigations into vitamin D receptor genetics or interactions with other micronutrients may further elucidate which subpopulations derive meaningful cardiometabolic benefits. Such research will help translate findings into personalized guidelines for pediatric patients facing overweight and obesity.
Bottom line
Vitamin D supplementation in overweight and obese children and adolescents shows potential benefits for certain cardiometabolic markers in selected groups, especially when deficiency is present. However, the evidence does not support a universal, large-scale cardiometabolic risk reduction from vitamin D alone. A holistic care plan that emphasizes weight management, diet quality, physical activity, and targeted vitamin D repletion remains the most effective strategy for improving pediatric cardiometabolic health.
