Reading levels of evidence: from cell culture to randomised trial
N. Thornton, MSc. · Molecular Biologist · 5 min · RARE Labs
Not every study carries the same weight. A short guide to placing nutrient claims realistically.
In vitro data show mechanisms, not effects. They are the start of a hypothesis, not its proof.
Observational studies describe associations in large groups; they can never fully exclude confounders.
Randomised controlled trials and their systematic reviews give the most robust answers — provided endpoints, dosage and duration are sensibly chosen.
What this means — and what it does not
- A plausible mechanism is not proof of efficacy.
- Dosage and nutrient form determine whether a result transfers at all.
Limitations
- Meta-analyses are only as good as the studies they include.
- Publication bias shifts the overall picture towards positive results.
Sources
- Umesh G et al., Indian J Anaesth 2016 — Critical appraisal of published literatureUmesh G, Karippacheril JG, Magazine R · Indian J Anaesth · 2016 · PMID: 27729695
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