The Claim

In elderly men, vitamin D supplementation during resistance training is associated with reduced CYP27B1 mRNA expression after training, which may reflect a negative feedback mechanism triggered by elevated serum 25(OH)D levels.

Source: Does vitamin-D intake during resistance training improve the skeletal muscle hypertrophic and strength response in young and elderly men? – a randomized controlled trial

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
53score
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.

How it works
1 study reviewed
In plain English

When older men take vitamin D pills while doing weight training, their bodies might slow down the production of a specific enzyme because they have too much vitamin D in their blood — like a safety switch turning itself off.

See the scientific wording

In elderly men, vitamin D supplementation during resistance training is associated with reduced CYP27B1 mRNA expression post-training, potentially indicating a negative feedback mechanism due to elevated serum 25(OH)D levels.

What the research says

1 study
  1. Study: Does vitamin-D intake during resistance training improve the skeletal muscle hypertrophic and strength response in young and elderly men? – a randomized controlled trial

    The study gave elderly men vitamin D while they did strength training and found their vitamin D levels shot up — and since the body usually slows down vitamin D processing when levels are high, this suggests the same thing happened here, even if not directly stated.

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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