The Study
Lean body mass accretion is elevated in response to dietary vitamin D: A dose-response study in female weanling rats.
This study looked at baby rats and found that those given more vitamin D in their food tended to have a bit more muscle, but we can't say the vitamin D caused it — maybe something else was different. And since it’s rats, we don’t know if it’s the same for kids or people.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Baby female rats got different amounts of vitamin D in their food for 8 weeks. Those with more vitamin D grew more muscle, but didn't get heavier or fatter.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 514 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Not directly applicable to humans; rats are not people, and doses are much higher than typical human intake.
- 2Rats with 4 IU/g vitamin D had 2x higher blood vitamin D levels than those with 1 IU/g.
- 3Muscle growth was 5%+ higher in 2 and 4 IU groups vs.
- 41 IU group.
- 5IGF-1 (a growth hormone) dropped less in the highest dose group.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrition research
Year
2019
Authors
M. Razaghi, Marija Djekić-Ivanković, S. Agellon, Ivy L Mak, P. Lavery, H. Weiler
Related Content
Claims (4)
Having more vitamin D in your body might help you build more muscle and store less fat, directing your body’s energy toward making lean tissue instead.
When young female rats eat more vitamin D3 in their food, they grow more muscle over 8 weeks, but their overall weight and fat don’t change.
When baby female rats get more vitamin D in their food, their body keeps more of a growth-related hormone called IGF-1 over 8 weeks, compared to rats getting less vitamin D.
When baby female rats eat more vitamin D3 in their food, their blood levels of a vitamin D marker go up — and the more they eat, the higher it goes.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.