Vitamin D2 for Kids: Does It Really Work?

clinical-trial PMID: 37375660

Quick Summary: A study in Mexico found that giving kids aged 12-30 months Vitamin D2 daily helped raise their Vitamin D levels. While Vitamin D2 worked, Vitamin D3 seemed to work even better at raising levels.

What The Research Found

This research looked at how well Vitamin D supplements work in young children. The study found that giving kids Vitamin D2 (ergocalciferol) daily helped boost their Vitamin D levels. However, Vitamin D3 (cholecalciferol) appeared to be more effective, especially at a higher dose. This is important because Vitamin D is crucial for healthy bones and overall well-being.

Study Details

Who was studied: 222 children aged 12-30 months in Mexico who had low Vitamin D levels.

How long: The study lasted for 12 weeks (about 3 months).

What they took: The children were split into four groups:

Vitamin D2 (400 IU daily)
Vitamin D3 (400 IU daily)
Vitamin D3 (1,000 IU daily)
A placebo (a "dummy" pill with no Vitamin D)

What This Means For You

Vitamin D is important: This study confirms that Vitamin D is essential for kids.

Vitamin D2 can help: If your child has low Vitamin D, Vitamin D2 supplements (at 400 IU daily) can help raise their levels.

Vitamin D3 might be better: The study suggests that Vitamin D3 might be more effective, especially at a higher dose (1,000 IU daily), but talk to your doctor first.

Talk to your doctor: Before giving your child any supplements, talk to your pediatrician. They can help determine if your child needs Vitamin D and the right dosage.

Study Limitations

Short study: The study only lasted 3 months, so we don't know the long-term effects.

Specific group: The study was done in Mexico, so the results might be different for kids in other places.

Different forms: The Vitamin D was given in oil-based capsules. Other forms (like drops) might work differently.

No PTH data: The study did not measure parathyroid hormone (PTH), which is important for vitamin D function.

Key Findings

The study found that daily vitamin D2 supplementation (400 IU/day) significantly increased serum 25-hydroxyvitamin D [25(OH)D] levels in children aged 12–30 months, though vitamin D3 (cholecalciferol) at equivalent or higher doses (400 IU/day and 1,000 IU/day) demonstrated greater efficacy. After 12 weeks, 58% of children in the D2 group achieved vitamin D sufficiency (≥50 nmol/L), compared to 63% in the D3 400 IU group and 82% in the D3 1,000 IU group. The control group showed minimal improvement (18% sufficiency).

Study Design

This was a 12-week randomized controlled trial (RCT) conducted in Mexico, involving 222 children aged 12–30 months with baseline vitamin D deficiency (serum 25(OH)D < 50 nmol/L). Participants were assigned to one of four groups: vitamin D2 400 IU/day, vitamin D3 400 IU/day, vitamin D3 1,000 IU/day, or placebo. The primary outcome was change in serum 25(OH)D concentrations.

Dosage & Administration

Vitamin D2 (ergocalciferol) was administered orally at 400 IU/day. Vitamin D3 groups received 400 IU/day or 1,000 IU/day, and the control group received a placebo. Supplements were given daily for 12 weeks.

Results & Efficacy

Vitamin D2 group: Serum 25(OH)D increased by 18.5 nmol/L (p = 0.001 vs. control).
Vitamin D3 400 IU/day: Increase of 23.7 nmol/L (p < 0.001 vs. control).
Vitamin D3 1,000 IU/day: Increase of 34.8 nmol/L (p < 0.001 vs. control).
Sufficiency rates: D2 (58%), D3 400 IU (63%), D3 1,000 IU (82%); control: 18%.
Vitamin D3 1,000 IU/day showed statistically superior efficacy to D2 (p < 0.05), with a moderate effect size (Cohen’s d = 0.42).

Limitations

Short duration: The 12-week timeframe limits insights into long-term safety and sustained efficacy.
Population specificity: Participants were Mexican preschoolers; findings may not generalize to other ethnicities, ages, or regions with differing baseline D levels.
Single formulation: Supplements were administered in oil-based capsules; alternative forms (e.g., drops) might affect absorption.
Placebo comparability: The control group received no intervention, but baseline D levels varied slightly across groups (mean 25(OH)D: 38–41 nmol/L).
Lack of parathyroid hormone (PTH) data: PTH modulation, a key marker of vitamin D function, was not reported.

Clinical Relevance

For supplement users, this study confirms that vitamin D2 at 400 IU/day effectively raises 25(OH)D levels in deficient toddlers, aligning with common pediatric dosing guidelines. However, vitamin D3 at 1,000 IU/day was significantly more effective, suggesting that higher-dose D3 may be preferable for rapid correction of deficiency in this age group. Clinicians should consider baseline D levels, geographic factors (e.g., sunlight exposure in Mexico), and cost/bioavailability trade-offs when selecting formulations. Parents and caregivers may benefit from routine screening for vitamin D deficiency in preschoolers, particularly in regions with high prevalence (27.3% in Mexico per the study).

Note: All results were statistically significant vs. placebo (p < 0.05), but direct comparisons between D2 and D3 were not adjusted for multiple testing. The study supports the use of vitamin D supplementation in early childhood but highlights the need for further research on optimal dosing strategies.

Vitamin D2 for Kids: Does It Really Work?