The Claim

High-dose beta-carotene supplementation increases the incidence of lung cancer in smokers.

Source: They Had to Stop This Vitamin C Trial Early

What the research says

Supports is higher

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

Supports

74score

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.

Cause and effect

1 study reviewed

In plain English

Smokers who take high-dose beta-carotene supplements have a higher rate of developing lung cancer than smokers who do not.

See the scientific wording

High-dose beta-carotene supplementation increases lung cancer incidence in smokers.

Why this might work

In smokers, high doses of beta-carotene break down into chemicals that react with lung tissue and cause DNA damage, which leads to cancer.

Supported mechanismbased on 2 studies

1 study

Study: The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers.
In a big study of smoking men, those who took daily beta-carotene supplements got more lung cancer than those who didn’t. So the supplements didn’t help — they actually made things worse.

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.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.