Three diseases caused by vitamin deficiencies—pellagra (niacin), scurvy (vitamin C), and beriberi (thiamine)—still affect people in the United States, even though many think they are a thing of the past.
See the scientific wording
Pellagra, scurvy, and beriberi occur in the United States, contrary to the common belief that these nutritional deficiency diseases have been eradicated.
Correlational — new studies may shift this
2 low-scoring studies link this claim to the outcome, but causation is not established.
What the research says
2 studies reviewedSupporting (2)
A comprehensive review on the co-occurrence of scurvy and anorexia nervosa
Systematic ReviewReview2024
This study shows that scurvy, a disease from not getting enough vitamin C, still happens in the US, especially in people with eating disorders—so part of the claim is true, but it doesn't talk about the other two diseases.
Scurvy in the Intensive Care Unit
Case ReportHuman2021
This study describes a real case of scurvy in a US hospital, showing that this old vitamin deficiency disease still exists today, just like the claim says.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 2 supporting studies
How Fit Body Science checks a claim
- 1
We isolate the claim
Health advice from videos, articles and studies is broken down into single, testable claims.
- 2
We find the research
Each claim is matched against peer-reviewed studies, with every source cited by DOI.
- 3
We grade the evidence
Studies are scored on methodology, statistical rigor, transparency and publication quality.
The fitness and health internet is full of confident claims. We check them against real research.
Every claim on this site is traced back to peer-reviewed studies, scored on methodology and reporting quality, and given a verdict you can audit yourself — sources, DOIs and all.
- Full evidence breakdown and mechanism chains
- Ask our AI anything about a claim or its studies
- Get notified when new research changes a verdict