The Claim

In rat L6 myoblasts, knockdown of the vitamin D receptor (VDR) reduces Myh7 gene expression to 37%, 29%, and 43% of control levels at 0 pM, 1 pM, and 10 pM 1,25-dihydroxyvitamin D3, respectively, but Myh7 expression is restored to control levels at 100 pM 1,25-dihydroxyvitamin D3.

Source: 1,25‐Dihydroxyvitamin D3 Mediates L6 Myoblast Differentiation via Vitamin D Receptor (VDR)

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
6score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

When scientists reduced a specific vitamin D sensor in rat muscle cells, the cells made less of a protein linked to slow-twitch muscles—unless they added a lot of vitamin D, then the protein came back.

See the scientific wording

In rat L6 myoblasts, knockdown of the vitamin D receptor (VDR) suppresses Myh7 gene expression (slow-twitch fiber marker) to 37%, 29%, and 43% of control levels at 0 pM, 1 pM, and 10 pM 1,25-dihydroxyvitamin D3, respectively, but expression is restored at 100 pM.

What the research says

1 study
  1. Study: 1,25‐Dihydroxyvitamin D3 Mediates L6 Myoblast Differentiation via Vitamin D Receptor (VDR)

    Scientists turned down the vitamin D receptor in rat muscle cells and saw that a slow-twitch muscle gene (Myh7) got weaker — unless they gave a high dose of vitamin D, which brought the gene back to normal. This matches exactly what the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

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