Beta-carotene supplements (with or without vitamin A) increased lung cancer and mortality in smokers and asbestos-exposed workers (CARET, ATBC), and the USPSTF recommends against them.
Original statement
وفي السرطان، أوقفت تجربة CARET عام 1996 مبكراً بعد أن رفع البيتا كاروتين وفيتامين A الإصابةَ بسرطان الرئة لدى المدخنين بنسبة 28%، وأكدت تجربة ATBC الفنلندية النتيجة نفسها. أما تجربة SELECT فأظهرت أن فيتامين E بجرعة 400 وحدة دولية يومياً يزيد سرطان البروستاتا بنسبة 17%.
not verbatim – paraphrase. Translation by the project; the Arabic wording is authoritative.
Translation
Beta-carotene supplements (with or without vitamin A) increased lung cancer and mortality in smokers and asbestos-exposed workers (CARET, ATBC), and the USPSTF recommends against them.
Origin
- Source status
- Archive editors
- Attribution
- Archive editors (eltayebat.com); not verified as Elawady's own words
- Origin
- https://eltayebat.com/rule/oral-supplements/
- Attribution uncertainty
- Written by the archive operators; study selection is the archive's, not necessarily Elawady's.
- Claimed mechanism
Not specified.
- Claimed health effect
Lung cancer, total mortality.
- Population concerned
Smokers, former smokers, asbestos workers.
- Geographic restriction by Elawady
none found
Scientific assessment
True – The statement is supported by robust evidence.
Certainty of evidence: high – Further research is very unlikely to change the assessment.
1. What was claimed?
Beta-carotene pills raise lung cancer risk in smokers.
2. What is demonstrably correct?
Correct: CARET RR 1.28 (1.04–1.57) for lung cancer and RR 1.17 for death from any cause; ATBC 18% higher lung cancer incidence and 8% higher total mortality with beta-carotene; USPSTF 2022 recommends against beta-carotene.
3. What is wrong or exaggerated?
Nothing substantial; 'confirmed the same verdict' should note that ATBC used beta-carotene alone and found no benefit of alpha-tocopherol on lung cancer.
4. What remains unclear?
Mechanism unclear.
5. Which studies support it?
A-SUP-04, A-SUP-05, A-SUP-24, A-SUP-30, I-SUP-08.
6. Which studies contradict it?
None.
7. What applies to Germany and Europe?
Applies equally.
8. What is known about Egypt?
Applies equally; smoking prevalence matters.
9. What practical conclusion is appropriate?
Smokers should not take beta-carotene supplements; vegetables and fruit containing carotenoids are a different matter.
Assessment details
- Rationale for certainty of evidence
Two large double-blind RCTs (18,314 and 29,133 participants) with consistent findings; pooled in USPSTF 2022 review (lung cancer OR 1.20; CV mortality OR 1.10); USPSTF D recommendation.
- Source quality
Correctly cited RCTs.
- Regional transferability
High.
- Individual exceptions
Findings are strongest in smokers; dietary beta-carotene from foods is a different exposure.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 26 October 2026 provisional
Scientific evidence in detail
Scientifically well supported – The claim agrees with consistent, high-quality evidence.
Research question: In smokers and asbestos-exposed workers, does beta-carotene (with or without vitamin A), compared with placebo, increase lung cancer and mortality?
Research question in detail (PICO)
- Population
- Smokers, former smokers, asbestos-exposed workers
- Intervention or exposure
- Beta-carotene 20-30 mg/day (+/- retinyl palmitate)
- Comparison
- Placebo
- Geographic scope
- universal biology
- Outcomes
- Lung cancer incidence
- All-cause mortality
Study results as reported by the authors. Our assessment follows below.
What speaks for the claim?
CARET: beta-carotene and vitamin A raised lung cancer in smokers
Omenn GS et al.. N Engl J Med 1996 · PMID 8602180 · DOI 10.1056/NEJM199605023341802 Randomised controlled trialabstract checkedCARET RCT: beta-carotene plus vitamin A increased lung cancer and death.
- Actual result
- Lung cancer RR 1.28 (1.04-1.57); death RR 1.17 (1.03-1.33).
- Methodological quality
- high (RCT)
- Relevance
- direct
- Limitations
- Stopped early.
ATBC: beta-carotene raised lung cancer in Finnish smokers
ATBC Study Group. N Engl J Med 1994 · PMID 8127329 · DOI 10.1056/NEJM199404143301501 Randomised controlled trialabstract checkedATBC RCT: beta-carotene increased lung cancer in male smokers.
- Actual result
- Lung cancer +18% (3-36%); total mortality +8% (1-16%).
- Methodological quality
- high (RCT)
- Relevance
- direct
- Limitations
- Men only.
Beta-carotene harm persisted after stopping (CARET)
Goodman GE et al.. J Natl Cancer Inst 2004 · PMID 15572756 · DOI 10.1093/jnci/djh320 Randomised controlled trialabstract checkednewly addedCARET post-intervention follow-up: excess persisted after stopping.
- Actual result
- Lung cancer RR 1.12 (0.97-1.31); death RR 1.08 (0.99-1.17).
- Methodological quality
- high (randomised follow-up)
- Relevance
- direct
- Limitations
- Not significant post-intervention.
What speaks against the claim?
No high-quality evidence against the claim was found.
What does the overall evidence say?
Editorial assessment based on the studies above – not itself a study result.
Which position is better supported?
Claim correct.
Why some studies weigh more
Two large RCTs plus pooled analyses (USPSTF, Cochrane).
Is a causal relationship established? Yes, established Randomised trials with consistent harm.
Remaining uncertainty
Mechanism; effect in non-smokers.
Justified conclusion
Smokers should not take beta-carotene supplements.
Does this depend on the country?
- General biological effects
- Universal biology.
- Eating habits
- Smoking prevalence determines the population at risk; smoking is common among men in Egypt (no figures reviewed).
- Origin of the food
- Not relevant.
- Contaminants
- Not relevant.
- National production conditions
- Not relevant.
- Legal rules
- Not relevant.
- Actual monitoring data
- None.
A regional difference that changes the conclusion is not supported by robust data.
Statistical re-check
- Low-bias beta-carotene crude vs pooled – Crude ratio 1.24 vs pooled RR 1.05 (1.01-1.09); use pooled. recalculated
Certainty of the overall evidence (GRADE, simplified)
- Main outcome
- Lung cancer in smokers with beta-carotene
- Starting level
- high (randomised trials)
- Result
- high
Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.
Clinical guidelines and official statements checked
- USPSTF: Vitamin, Mineral, and Multivitamin Supplementation to Prevent CVD and Cancer (A-SUP-30) (2022) · Original publication
Recommends against beta-carotene and vitamin E for prevention of CVD and cancer; evidence insufficient for most other supplements (record re-checked via PubMed efetch 2026-10-26; recommendation grades taken from the existing record).
Search strategy
Documented literature searches for this review (search strings in the original database syntax).
| Database | Date | Search | Looking for | Hits | Included |
|---|---|---|---|---|---|
| Europe PMC | 26 October 2026 | (TITLE:"beta-carotene" OR TITLE:"beta carotene" OR TITLE:"β-carotene") AND (TITLE:"lung cancer") AND (TITLE:"follow-up" OR TITLE:postintervention OR TITLE:"post-intervention" OR PUB_TYPE:"Meta-Analysis") | both directions | 4 | |
| Europe PMC | 26 October 2026 | TITLE:"antioxidant supplements" AND TITLE:mortality AND JOURNAL:"Cochrane Database Syst Rev" | supporting evidence | 2 |
Open questions
None material.
How deeply was this checked?
7 linked studies: 0 checked in full text (0 of them with a structured risk-of-bias assessment), 7 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.
Last scientific review: 26 October 2026
History of the verdict
In plain language
Two large trials gave smokers beta-carotene pills hoping to prevent lung cancer. Instead, more of them got lung cancer and died. US prevention experts therefore advise against these pills. This claim is correct.
Studies on this claim
Studies supporting the claim (7)
-
CARET: beta-carotene and vitamin A raised lung cancer in smokers
Omenn GS et al.. N Engl J Med 1996 · PMID 8602180 · DOI 10.1056/NEJM199605023341802Randomised controlled trialcited by the Tayebat archiveabstract checked★ key studyLung cancer was 28% more frequent with the supplements; the trial was stopped early.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Prevent lung cancer?
- How was the study done?
RCT.
- How many people, animals or samples were studied?
18,314 high-risk adults.
- What was actually found?
More lung cancer, more deaths.
- How large was the observed effect?
RR 1.28; 1.17.
- What do the results mean in everyday life?
Smokers should avoid beta-carotene pills.
- What are the study's limitations?
Early stopping.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Effect in non-smokers.
-
ATBC: beta-carotene raised lung cancer in Finnish smokers
ATBC Study Group. N Engl J Med 1994 · PMID 8127329 · DOI 10.1056/NEJM199404143301501Randomised controlled trialcited by the Tayebat archiveabstract checkedBeta-carotene raised lung cancer by 18% and deaths by 8%; vitamin E did not prevent lung cancer.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Cancer prevention in smokers.
- How was the study done?
Factorial RCT.
- How many people, animals or samples were studied?
29,133 men.
- What was actually found?
Harm from beta-carotene.
- How large was the observed effect?
+18% lung cancer.
- What do the results mean in everyday life?
Avoid beta-carotene pills.
- What are the study's limitations?
Men smokers only.
- What does it say about Elawady's specific claim?
Supports C-SUP-02.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Non-smokers.
-
Antioxidant pills and mortality
Bjelakovic G et al.. JAMA 2007 · PMID 17327526 · DOI 10.1001/jama.297.8.842Meta-analysiscited by the Tayebat archiveabstract checked★ key studyIn low-bias trials, beta-carotene, vitamin A and vitamin E were linked to slightly more deaths.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Mortality.
- How was the study done?
Meta-analysis.
- How many people, animals or samples were studied?
232,606.
- What was actually found?
Small increase in low-bias trials.
- How large was the observed effect?
RR 1.05.
- What do the results mean in everyday life?
No benefit, possible harm.
- What are the study's limitations?
Debated methods.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Precise harm.
-
USPSTF 2022: vitamins for prevention
US Preventive Services Task Force et al.. JAMA 2022 · PMID 35727271 · DOI 10.1001/jama.2022.8970Guideline / position statementcited by the Tayebat archiveabstract checked★ key studyRecommends against beta-carotene and vitamin E; evidence insufficient for most others.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Prevention guidance.
- How was the study done?
Guideline.
- What was actually found?
D for beta-carotene, vitamin E; I for others.
- What do the results mean in everyday life?
Don't take for prevention.
- What are the study's limitations?
Not for pregnancy/deficiency.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Advice on deficiency or pregnancy.
-
USPSTF evidence review 2022
O'Connor EA et al.. JAMA 2022 · PMID 35727272 · DOI 10.1001/jama.2021.15650Systematic reviewindependent cross-checkabstract checked★ key studySupplements gave little or no protection; beta-carotene harmful; multivitamins slightly fewer cancers.
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Supplement benefits/harms.
- How was the study done?
SR.
- How many people, animals or samples were studied?
739,803.
- What was actually found?
Little benefit; some harms.
- How large was the observed effect?
OR 0.93 MV cancer; 1.20 beta-carotene lung cancer.
- What do the results mean in everyday life?
Supplements are not a prevention strategy.
- What are the study's limitations?
Not for deficiency.
- What does it say about Elawady's specific claim?
Mixed.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Effects in deficient people.
-
Beta-carotene harm persisted after stopping (CARET)
Goodman GE et al.. J Natl Cancer Inst 2004 · PMID 15572756 · DOI 10.1093/jnci/djh320Randomised controlled trialindependent cross-checkabstract checkedSix years after stopping the pills, lung cancer and deaths were still somewhat higher in the beta-carotene group.
Excess lung cancer and mortality persisted (non-significantly) after stopping beta-carotene + vitamin A.
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
To follow CARET participants after the trial stopped.
- How was the study done?
Follow-up of a randomised trial.
- How many people, animals or samples were studied?
18,314 high-risk adults.
- What was actually found?
Lung cancer RR 1.12 and death RR 1.08 after stopping.
- How large was the observed effect?
RR 1.12 (0.97-1.31).
- What do the results mean in everyday life?
Smokers should not take beta-carotene pills.
- What are the study's limitations?
Not statistically significant after stopping.
- What does it say about Elawady's specific claim?
Supports C-SUP-02.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Not about carotenoids in food.
-
Antioxidant pills and death: Cochrane review
Bjelakovic G et al.. Cochrane Database Syst Rev 2012 · PMID 22419320 · DOI 10.1002/14651858.CD007176.pub2Meta-analysisindependent cross-checkabstract checked★ key studyIn 78 trials, antioxidant pills did not lower death rates; beta-carotene and vitamin E slightly increased them in the best trials.
Beta-carotene increased mortality in low-bias trials (RR 1.05).
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
To see whether antioxidant supplements prevent death.
- How was the study done?
Cochrane meta-analysis of randomised trials.
- How many people, animals or samples were studied?
78 trials; 296,707 people.
- What was actually found?
No benefit; small increase in deaths with beta-carotene and vitamin E in low-bias trials.
- How large was the observed effect?
Low-bias RR 1.04 (1.01-1.07); beta-carotene 1.05; vitamin E 1.03.
- What do the results mean in everyday life?
Antioxidant pills do not help you live longer and some may slightly shorten life.
- What are the study's limitations?
Mixed populations; older search.
- What does it say about Elawady's specific claim?
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Does not apply to antioxidants in food.
No study in this group is marked as key.
Studies contradicting or limiting the claim (0)
No studies in this group.
Studies with mixed or unclear results (0)
No studies in this group.
Regional context
Germany / EU
Applies equally.
Egypt
Applies equally; smoking prevalence matters.
What applies in my country?
General scientific assessment
True True: beta-carotene pills increased lung cancer in smokers.
This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.
References
- Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease.. Omenn GS et al.. N Engl J Med 1996 · PMID 8602180 · DOI 10.1056/NEJM199605023341802
- The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers.. ATBC Study Group. N Engl J Med 1994 · PMID 8127329 · DOI 10.1056/NEJM199404143301501
- Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis.. Bjelakovic G et al.. JAMA 2007 · PMID 17327526 · DOI 10.1001/jama.297.8.842
- Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement.. US Preventive Services Task Force et al.. JAMA 2022 · PMID 35727271 · DOI 10.1001/jama.2022.8970
- Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.. O'Connor EA et al.. JAMA 2022 · PMID 35727272 · DOI 10.1001/jama.2021.15650
- The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements.. Goodman GE et al.. J Natl Cancer Inst 2004 · PMID 15572756 · DOI 10.1093/jnci/djh320
- Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases.. Bjelakovic G et al.. Cochrane Database Syst Rev 2012 · PMID 22419320 · DOI 10.1002/14651858.CD007176.pub2