Mostly true Scientifically well supported Certainty of evidence: high provisional C-SUP-01

When popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A) were tested in large long-term placebo-controlled trials, most failed to deliver the promised prevention of disease.

In short: This claim is largely correct: in large placebo-controlled trials most popular supplements did not prevent heart disease, cancer or death in healthy adults; this does not apply to people with a deficiency, to pregnancy or to prescription indications.

Conclusion: Largely correct for disease prevention in healthy adults.

Original statement
Scientific assessment
Scientific evidence in detail
In plain language
Studies on this claim
Regional context
What applies in my country?
References

Original statement

حين أُخضعت المكملات الفموية الأكثر مبيعاً — من الكالسيوم والبيتا كاروتين وفيتامين E، إلى أوميغا-3 والمتعددات والجلوكوزامين والسيلينيوم وفيتامين A — لاختبارات عشوائية مضبوطة بالغفل وبأحجام كبيرة ومتابعة طويلة، لم تَفِ في الغالب بوعودها؛ بل أن بعضها أحدث ضرراً صريحاً: زيادة في الوفيات، وفي سرطان الرئة والبروستاتا، وفي احتشاء عضلة القلب، وفي الرجفان الأذيني، وفي كسور الورك، وفي حصى الكلى. ما يُسوَّق على أنه «وقاية» انقلب في عدة تجارب إلى مصدر للأذى.

not verbatim – paraphrase. Translation by the project; the Arabic wording is authoritative.

Translation

When popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A) were tested in large long-term placebo-controlled trials, most failed to deliver the promised prevention of disease.

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: Isolated nutrients in pills do not reproduce the benefits of foods.
Claimed health effect: No prevention of CVD, cancer or death.
Population concerned: Generally healthy adults without deficiency.
Geographic restriction by Elawady: none found

Scientific assessment

Mostly true – Correct at its core, but with limitations or minor inaccuracies.

Certainty of evidence: high – Further research is very unlikely to change the assessment.

1. What was claimed?

Supplements failed in big trials.

2. What is demonstrably correct?

Correct for prevention of cardiovascular disease, cancer and death in well-nourished adults; USPSTF 2022 found the evidence insufficient for most supplements and recommended against beta-carotene and vitamin E.

3. What is wrong or exaggerated?

The summary generalises from 'no benefit for prevention' to 'unnecessary for everyone', which ignores deficiency treatment and pregnancy. It omits that multivitamins showed a small cancer-incidence benefit in pooled RCTs and that the Cochrane omega-3 review found a small reduction in coronary events.

4. What remains unclear?

Effects in populations with poor diets (where deficiencies are common) are less studied.

5. Which studies support it?

A-SUP-07–10, A-SUP-13, A-SUP-22, A-SUP-25–27, A-SUP-29, A-SUP-30; O'Connor 2022 (I-SUP-08).

6. Which studies contradict it?

REDUCE-IT (I-SUP-09) as a high-dose prescription exception; O'Connor 2022 small multivitamin cancer benefit.

7. What applies to Germany and Europe?

EU regulators and German bodies (BfR) also caution against high-dose supplements; not fetched here.

8. What is known about Egypt?

Where diets are restricted, the balance may differ (deficiency risk).

9. What practical conclusion is appropriate?

For healthy, well-nourished adults, routine supplements for disease prevention are generally not justified; this does not apply to diagnosed deficiencies or pregnancy.

Assessment details

Rationale for certainty of evidence: Consistent with the USPSTF 2022 evidence review (84 studies; little or no benefit for CVD, cancer and death) and many large RCTs (VITAL, ASCEND, PHS II, SELECT, GAIT). Exceptions: a small reduction in cancer incidence with multivitamins (OR 0.93) and high-dose prescription EPA in high-risk patients (REDUCE-IT).
Source quality: Archive summary well supported for primary prevention in non-deficient adults.
Regional transferability: High; trials mostly US/Europe.
Individual exceptions: Does not apply to people with deficiencies or specific indications (see C-SUP-10).
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 generally healthy, non-deficient adults, do popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A), compared with placebo, prevent cardiovascular disease, cancer or death in large long-term RCTs?

Research question in detail (PICO)

Population

Generally healthy adults without deficiency

Intervention or exposure

Oral vitamin/mineral/omega-3/glucosamine supplements

Comparison

Placebo

Geographic scope

universal biology

Outcomes

Cardiovascular events
Cancer incidence
All-cause mortality
Osteoarthritis pain (glucosamine)

Study results as reported by the authors. Our assessment follows below.

What speaks for the claim?

USPSTF evidence review 2022

O'Connor EA et al.. JAMA 2022 · PMID 35727272 · DOI 10.1001/jama.2021.15650 Systematic reviewabstract checked

USPSTF 2022 evidence review: 84 studies; little or no benefit of most supplements for CVD, cancer or death.

Actual result
Vitamin E mortality OR 1.02 (n.s.); vitamin D mortality OR 0.96 (n.s.); beta-carotene lung cancer OR 1.20 (1.01-1.42).
Methodological quality
high (systematic review for a guideline body)
Relevance
direct
Limitations
Mainly well-nourished populations; short follow-up in many trials.

Original publication
Antioxidant pills and death: Cochrane review

Bjelakovic G et al.. Cochrane Database Syst Rev 2012 · PMID 22419320 · DOI 10.1002/14651858.CD007176.pub2 Meta-analysisabstract checkednewly added

Cochrane review of 78 antioxidant RCTs: no mortality benefit; small excess with beta-carotene and vitamin E in low-bias trials.

Actual result
All trials RR 1.02 (0.98-1.05); low-bias trials RR 1.04 (1.01-1.07).
Methodological quality
high (Cochrane)
Relevance
direct
Limitations
Overlaps A-SUP-24; search 2011.

Original publication
Daily multivitamin in older adults (COSMOS trial)

Sesso HD et al.. Am J Clin Nutr 2022 · PMID 35294969 · DOI 10.1093/ajcn/nqac056 Randomised controlled trialabstract checkednewly added

COSMOS: daily multivitamin in 21,442 older adults did not reduce cancer or CVD.

Actual result
Cancer HR 0.97 (0.86-1.09); CVD HR 0.98 (0.86-1.12); death HR 0.93 (0.81-1.08).
Methodological quality
high (large double-blind RCT)
Relevance
direct
Limitations
3.6-year median follow-up.

Original publication

What speaks against the claim?

REDUCE-IT: prescription EPA

Bhatt DL et al.. N Engl J Med 2019 · PMID 30415628 · DOI 10.1056/NEJMoa1812792 Randomised controlled trialabstract checked

REDUCE-IT: 4 g/day prescription icosapent ethyl reduced CV events in high-risk statin-treated patients.

Actual result
Primary end point 17.2% vs 22.0%, HR 0.75 (0.68-0.83).
Methodological quality
high (large RCT), but placebo (mineral oil) debated
Relevance
indirect (prescription drug in high-risk patients, not a popular supplement)
Limitations
Not generalisable to OTC capsules.

Original publication
USPSTF evidence review 2022

O'Connor EA et al.. JAMA 2022 · PMID 35727272 · DOI 10.1001/jama.2021.15650 Systematic reviewabstract checked

Same USPSTF review: multivitamins associated with a small reduction in cancer incidence.

Actual result
Any cancer OR 0.93 (0.87-0.99).
Methodological quality
high
Relevance
direct
Limitations
Small effect; COSMOS (I-SUP-106) found HR 0.97 (n.s.).

Original publication

What does the overall evidence say?

Editorial assessment based on the studies above – not itself a study result.

Which position is better supported?

For healthy, non-deficient adults most popular supplements do not prevent CVD, cancer or death in large RCTs.

Why some studies weigh more

Large double-blind RCTs and Cochrane/USPSTF syntheses outweigh observational data; overlapping meta-analyses (A-SUP-24/I-SUP-108; I-SUP-08/A-SUP-30) counted once.

Is a causal relationship established? Yes, established Randomised evidence directly tests prevention and is consistently null for most agents.

Remaining uncertainty

Small effects (e.g. multivitamins and cancer, OR 0.93) and effects in poorly nourished populations.

Justified conclusion

The archive summary is correct for prevention in well-nourished adults; it does not extend to deficiency, pregnancy or prescription indications.

Why do studies seem to disagree?

Multivitamin-cancer: USPSTF pooled OR 0.93 and PHS II benefit vs COSMOS null - different populations and follow-up; effect small either way. Omega-3: low-dose null vs high-dose EPA benefit - different formulation and population.

Does this depend on the country?

General biological effects: Same human physiology everywhere.
Eating habits: Supplement use patterns differ by country; not region-specific for this question.
Origin of the food: Not relevant.
Contaminants: Product quality and contamination vary by market (not assessed here).
National production conditions: Not relevant.
Legal rules: Supplements are regulated as foods in the EU; Egyptian rules not verified.
Actual monitoring data: No monitoring data reviewed.

A regional difference that changes the conclusion is not supported by robust data.

Statistical re-check

Crude pooled proportions vs pooled RR; CI symmetry – Crude ratio 1.15 vs pooled RR 1.02: factorial designs inflate crude ratios; pooled RRs valid; CIs approximately log-symmetric. recalculated
Crude cancer risk and mortality P value – Approximate crude RR 0.97 matches HR; recomputed P for mortality HR 0.93 (0.81-1.08) about 0.32. recalculated

Certainty of the overall evidence (GRADE, simplified)

Main outcome: All-cause mortality and CVD/cancer prevention in healthy adults
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
Europe PMC	26 October 2026	`TITLE:multivitamin AND (TITLE:mortality OR TITLE:cancer OR TITLE:"cardiovascular") AND PUB_YEAR:[2019 TO 2026]`	both directions	28
Europe PMC	26 October 2026	`TITLE:"antioxidant supplements" AND TITLE:mortality AND JOURNAL:"Cochrane Database Syst Rev"`	supporting evidence	2
PubMed	26 October 2026	`(vitamin[ti] OR supplement[ti] OR antioxidant*[ti]) AND (mortality[ti] OR "cardiovascular"[ti] OR cancer[ti]) AND (meta-analysis[pt]) AND 2018:2026[dp] AND (randomized[tiab] OR trials[tiab])`	supporting evidence	180
PubMed	26 October 2026	`(multivitamin*[ti] OR "vitamin D"[ti] OR "omega-3"[ti]) AND (benefit[tiab] OR reduced[tiab]) AND (randomized controlled trial[pt]) AND (cancer[ti] OR mortality[ti] OR cardiovascular[ti]) AND 2019:2026[dp]`	contradicting evidence	25
Europe PMC	26 October 2026	`TITLE:selenium AND TITLE:"preventing cancer" AND JOURNAL:"Cochrane Database Syst Rev"`	supporting evidence	3
Europe PMC	26 October 2026	`TITLE:glucosamine AND TITLE:knee AND (PUB_TYPE:"Meta-Analysis") AND PUB_YEAR:[2015 TO 2026]`	supporting evidence	9
PubMed	26 October 2026	`USPSTF 2022 recommendation record PMID 35727271 (efetch)`	guidelines	1

Open questions

Effects in populations with restricted diets (relevant to followers of the Tayebat food lists) are not tested by these trials.

How deeply was this checked?

20 linked studies: 0 checked in full text (0 of them with a structured risk-of-bias assessment), 20 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

25 October 2026 · Phase 1 · Initial assessment: Mostly true (high)
26 October 2026 · Phase 4 (systematic evidence review) · Re-examined with extended evidence; verdict unchanged: Mostly true (high)
New RCT (COSMOS), Cochrane antioxidant review, Cochrane selenium review and glucosamine IPD analysis all confirm lack of preventive benefit; no evidence changes the verdict.
New sources: I-SUP-106 I-SUP-107 I-SUP-108 I-SUP-117 I-SUP-118

In plain language

Large, careful trials have tested many popular vitamin and mineral pills. For healthy people who eat well, most did not prevent heart disease, cancer or early death. This is a fair summary. It does not mean that supplements are useless for people who lack a vitamin or who are pregnant.

Studies on this claim

Studies supporting the claim (17)

Low-dose omega-3 after heart attack

Kromhout D et al.. N Engl J Med 2010 · PMID 20929341 · DOI 10.1056/NEJMoa1003603

Randomised controlled trialcited by the Tayebat archiveabstract checked

No reduction in cardiovascular events.

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?
Omega-3 after MI.
How was the study done?
RCT.
How many people, animals or samples were studied?
4,837.
What was actually found?
No effect.
How large was the observed effect?
HR 1.01.
What do the results mean in everyday life?
Low doses don't help.
What are the study's limitations?
Low dose.
What does it say about Elawady's specific claim?
Supports.
Do the results apply to Germany and Europe?
Dutch.
What can explicitly not be concluded from this study?
High-dose effects.
Scientific details →
VITAL: fish oil in healthy adults

Manson JE et al.. N Engl J Med 2019 · PMID 30415637 · DOI 10.1056/NEJMoa1811403

Randomised controlled trialcited by the Tayebat archiveabstract checked

No reduction in major cardiovascular events or 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?
Primary prevention.
How was the study done?
RCT.
How many people, animals or samples were studied?
25,871.
What was actually found?
Null primary end points.
How large was the observed effect?
HR 0.92.
What do the results mean in everyday life?
Not needed for prevention.
What are the study's limitations?
Fewer MIs secondary.
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 high-risk.
Scientific details →
ASCEND: fish oil in diabetes

ASCEND Study Collaborative Group et al.. N Engl J Med 2018 · PMID 30146932 · DOI 10.1056/NEJMoa1804989

Randomised controlled trialcited by the Tayebat archiveabstract checked

No reduction in serious vascular events.

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?
Diabetes prevention.
How was the study done?
RCT.
How many people, animals or samples were studied?
15,480.
What was actually found?
Null.
How large was the observed effect?
RR 0.97.
What do the results mean in everyday life?
Not useful.
What does it say about Elawady's specific claim?
Supports.
Do the results apply to Germany and Europe?
UK.
Scientific details →
STRENGTH: high-dose omega-3

Nicholls SJ et al.. JAMA 2020 · PMID 33190147 · DOI 10.1001/jama.2020.22258

Randomised controlled trialcited by the Tayebat archiveabstract checked

No benefit vs corn oil; more GI side effects.

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?
High-dose omega-3.
How was the study done?
RCT.
How many people, animals or samples were studied?
13,078.
What was actually found?
Null.
How large was the observed effect?
HR 0.99.
What do the results mean in everyday life?
Not useful.
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?
Why REDUCE-IT differs.
Scientific details →
Glucosamine for knee pain (GAIT)

Clegg DO et al.. N Engl J Med 2006 · PMID 16495392 · DOI 10.1056/NEJMoa052771

Randomised controlled trialcited by the Tayebat archiveabstract checked

Not better than placebo overall.

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?
Knee OA pain.
How was the study done?
RCT.
How many people, animals or samples were studied?
1,583.
What was actually found?
No overall benefit.
How large was the observed effect?
+3.9 points n.s.
What do the results mean in everyday life?
Little benefit.
What are the study's limitations?
Subgroup.
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?
Harm.
Scientific details →
VITAL: vitamin D for prevention

Manson JE et al.. N Engl J Med 2019 · PMID 30415629 · DOI 10.1056/NEJMoa1809944

Randomised controlled trialcited by the Tayebat archiveabstract checked

No prevention of cancer or heart disease; no safety problems.

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.
How was the study done?
RCT.
How many people, animals or samples were studied?
25,871.
What was actually found?
Null.
How large was the observed effect?
HR 0.96/0.97.
What do the results mean in everyday life?
No need in replete adults.
What are the study's limitations?
Replete population.
What does it say about Elawady's specific claim?
Supports C-SUP-01.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
Effect in deficiency.
Scientific details →
PHS II: multivitamins and heart disease

Sesso HD et al.. JAMA 2012 · PMID 23117775 · DOI 10.1001/jama.2012.14805

Randomised controlled trialcited by the Tayebat archiveabstract checked

No reduction in heart attacks or strokes; no increase in deaths.

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?
CV prevention.
How was the study done?
RCT.
How many people, animals or samples were studied?
14,641.
What was actually found?
Null.
How large was the observed effect?
HR 1.01.
What do the results mean in everyday life?
Not needed for heart.
What are the study's limitations?
Physicians.
What does it say about Elawady's specific claim?
Supports C-SUP-01; contradicts C-SUP-06.
Do the results apply to Germany and Europe?
Applicable.
Scientific details →
Multivitamins and death – trials

Macpherson H et al.. Am J Clin Nutr 2013 · PMID 23255568 · DOI 10.3945/ajcn.112.049304

Meta-analysiscited by the Tayebat archiveabstract checked

No effect on mortality.

Does the study support the specific claim? No · 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?
Mortality.
How was the study done?
Meta-analysis.
How many people, animals or samples were studied?
91,074.
What was actually found?
No effect.
How large was the observed effect?
RR 0.98.
What do the results mean in everyday life?
Neither harm nor benefit.
What does it say about Elawady's specific claim?
Contradicts mortality claim.
Do the results apply to Germany and Europe?
Applicable.
Scientific details →
Multivitamins and memory

Grodstein F et al.. Ann Intern Med 2013 · PMID 24490265 · DOI 10.7326/0003-4819-159-12-201312170-00006

Randomised controlled trialcited by the Tayebat archiveabstract checked

No benefit for cognition.

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?
Cognition.
How was the study done?
RCT.
How many people, animals or samples were studied?
5,947.
What was actually found?
Null.
How large was the observed effect?
−0.01 SU.
What do the results mean in everyday life?
No brain benefit.
What are the study's limitations?
Well-nourished.
What does it say about Elawady's specific claim?
Supports.
Do the results apply to Germany and Europe?
Applicable.
Scientific details →
Vitamins and heart disease – overview

Jenkins DJA et al.. J Am Coll Cardiol 2018 · PMID 29852980 · DOI 10.1016/j.jacc.2018.04.020

Meta-analysiscited by the Tayebat archiveabstract checked

Mostly no effect; folic acid may reduce stroke; antioxidant mixtures may increase mortality.

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?
CVD prevention.
How was the study done?
Meta-analyses.
How many people, animals or samples were studied?
Many RCTs.
What was actually found?
Mostly null.
How large was the observed effect?
not in abstract
What do the results mean in everyday life?
Selective use.
What are the study's limitations?
Abstract only.
What does it say about Elawady's specific claim?
Mixed.
Do the results apply to Germany and Europe?
Applicable.
Scientific details →
USPSTF 2022: vitamins for prevention

US Preventive Services Task Force et al.. JAMA 2022 · PMID 35727271 · DOI 10.1001/jama.2022.8970

Guideline / position statementcited by the Tayebat archiveabstract checked★ key study

Recommends 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.
Scientific details →
USPSTF evidence review 2022

O'Connor EA et al.. JAMA 2022 · PMID 35727272 · DOI 10.1001/jama.2021.15650

Systematic reviewindependent cross-checkabstract checked★ key study

Supplements 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.
Scientific details →
Daily multivitamin in older adults (COSMOS trial)

Sesso HD et al.. Am J Clin Nutr 2022 · PMID 35294969 · DOI 10.1093/ajcn/nqac056

Randomised controlled trialindependent cross-checkabstract checked★ key study

Over 3.6 years a daily multivitamin neither reduced nor increased cancer, heart disease or deaths.

No reduction of cancer or CVD with a daily multivitamin.

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?
To test whether a daily multivitamin prevents cancer and heart disease.
How was the study done?
Randomised placebo-controlled trial.
How many people, animals or samples were studied?
21,442 older US adults.
What was actually found?
No effect on total cancer, CVD or deaths; possible fewer lung cancers (secondary).
How large was the observed effect?
Cancer HR 0.97 (0.86-1.09); death HR 0.93 (0.81-1.08).
What do the results mean in everyday life?
Multivitamins do not prevent major diseases in well-fed older people, and did not cause harm.
What are the study's limitations?
Short follow-up.
What does it say about Elawady's specific claim?
Supports C-SUP-01; contradicts C-SUP-06.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
Cannot exclude small long-term effects.
Scientific details →
Multivitamins and death in 390,000 Americans

Loftfield E et al.. JAMA Netw Open 2024 · PMID 38922615 · DOI 10.1001/jamanetworkopen.2024.18729

Cohort studyindependent cross-checkabstract checked

People who took multivitamins did not live longer; their risk of death was about 4% higher, which may reflect who takes supplements rather than the pills.

No mortality benefit of multivitamins over up to 27 years.

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?
To see whether multivitamin users live longer.
How was the study done?
Three large cohort studies combined.
How many people, animals or samples were studied?
390,124 adults.
What was actually found?
No survival benefit; slight 4% higher death risk.
How large was the observed effect?
HR 1.04 (1.02-1.07).
What do the results mean in everyday life?
Multivitamins do not help healthy people live longer.
What are the study's limitations?
Observational; self-report.
What does it say about Elawady's specific claim?
Supports C-SUP-01; only weakly relevant to the harm claim in C-SUP-06.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
Cannot prove that multivitamins cause harm.
Scientific details →
Antioxidant pills and death: Cochrane review

Bjelakovic G et al.. Cochrane Database Syst Rev 2012 · PMID 22419320 · DOI 10.1002/14651858.CD007176.pub2

Meta-analysisindependent cross-checkabstract checked★ key study

In 78 trials, antioxidant pills did not lower death rates; beta-carotene and vitamin E slightly increased them in the best trials.

No benefit of antioxidant supplements on mortality.

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?
Supports C-SUP-01, C-SUP-02 and partly C-SUP-03.
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.
Scientific details →
Selenium for preventing cancer: Cochrane review

Vinceti M et al.. Cochrane Database Syst Rev 2018 · PMID 29376219 · DOI 10.1002/14651858.CD005195.pub4

Meta-analysisindependent cross-checkabstract checked

Selenium pills did not prevent cancer, and trials hinted at more type 2 diabetes.

Selenium does not prevent cancer (high certainty).

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 test selenium for cancer prevention.
How was the study done?
Cochrane review of trials and cohorts.
How many people, animals or samples were studied?
10 trials (27,232 people); 70 cohorts.
What was actually found?
No cancer prevention; possible more diabetes and high-grade prostate cancer in some.
How large was the observed effect?
Cancer RR 1.01 (0.93-1.10).
What do the results mean in everyday life?
Selenium pills are not useful for cancer prevention.
What are the study's limitations?
Diabetes risk not quantified here.
What does it say about Elawady's specific claim?
Supports C-SUP-01 and C-SUP-07.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
Not about selenium-deficient regions.
Scientific details →
Glucosamine for knee and hip arthritis

Runhaar J et al.. Ann Rheum Dis 2017 · PMID 28754801 · DOI 10.1136/annrheumdis-2017-211149

Meta-analysisindependent cross-checkabstract checked

Using raw data from five independent trials, glucosamine was no better than a dummy pill for pain or function.

Example of a popular supplement without benefit.

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 test glucosamine in osteoarthritis subgroups.
How was the study done?
Individual patient data meta-analysis.
How many people, animals or samples were studied?
1,625 patients in placebo trials.
What was actually found?
No benefit overall or in any subgroup.
How large was the observed effect?
Not given.
What do the results mean in everyday life?
Glucosamine is unlikely to help arthritis pain.
What are the study's limitations?
Not all trials shared data.
What does it say about Elawady's specific claim?
Supports C-SUP-07 and C-SUP-01.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
Cannot rule out effects of specific products.
Scientific details →

Studies contradicting or limiting the claim (1)

REDUCE-IT: prescription EPA

Bhatt DL et al.. N Engl J Med 2019 · PMID 30415628 · DOI 10.1056/NEJMoa1812792

Randomised controlled trialindependent cross-checkabstract checked

High-dose purified EPA reduced cardiovascular events by 25% in high-risk patients; more AF.

Does the study support the specific claim? No · 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?
High-dose EPA.
How was the study done?
RCT.
How many people, animals or samples were studied?
8,179.
What was actually found?
Fewer events.
How large was the observed effect?
HR 0.75.
What do the results mean in everyday life?
Exception to 'omega-3 useless'.
What are the study's limitations?
Industry; placebo debate.
What does it say about Elawady's specific claim?
Limits C-SUP-05.
Do the results apply to Germany and Europe?
Applicable.
What can explicitly not be concluded from this study?
OTC capsules.
Scientific details →

Studies with mixed or unclear results (2)

Cochrane: omega-3 and heart health

Abdelhamid AS et al.. Cochrane Database Syst Rev 2020 · PMID 32114706 · DOI 10.1002/14651858.CD003177.pub5

Meta-analysiscited by the Tayebat archiveabstract checked

Little or no effect on deaths; small reductions in coronary events (low certainty).

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?
Omega-3 effects.
How was the study done?
Cochrane review.
How many people, animals or samples were studied?
162,796.
What was actually found?
Little effect on death; small CHD benefit.
How large was the observed effect?
RR 0.91 CHD events.
What do the results mean in everyday life?
Modest benefit at most.
What are the study's limitations?
Low certainty.
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?
Large benefits.
Scientific details →
Editorial against supplements

Guallar E et al.. Ann Intern Med 2013 · PMID 24490268 · DOI 10.7326/0003-4819-159-12-201312170-00011

Othercited by the Tayebat archiveabstract checked

Opinion; not read.

Does the study support the specific claim? Unclear · Methodological quality: very low · Certainty of evidence: see overall assessment of the claim

Original publication · Scientific details

Study explained simply
What did the researchers want to find out?
Opinion.
How was the study done?
Editorial.
What are the study's limitations?
Opinion.
What does it say about Elawady's specific claim?
Consistent title.
What can explicitly not be concluded from this study?
Evidence.
Scientific details →

Regional context

Germany / EU

EU regulators and German bodies (BfR) also caution against high-dose supplements; not fetched here.

Egypt

Where diets are restricted, the balance may differ (deficiency risk).

What applies in my country?

General scientific assessment

Mostly true Largely correct for disease prevention in healthy adults.

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

n-3 fatty acids and cardiovascular events after myocardial infarction.. Kromhout D et al.. N Engl J Med 2010 · PMID 20929341 · DOI 10.1056/NEJMoa1003603
Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer.. Manson JE et al.. N Engl J Med 2019 · PMID 30415637 · DOI 10.1056/NEJMoa1811403
Effects of n-3 Fatty Acid Supplements in Diabetes Mellitus.. ASCEND Study Collaborative Group et al.. N Engl J Med 2018 · PMID 30146932 · DOI 10.1056/NEJMoa1804989
Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk: The STRENGTH Randomized Clinical Trial.. Nicholls SJ et al.. JAMA 2020 · PMID 33190147 · DOI 10.1001/jama.2020.22258
Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis.. Clegg DO et al.. N Engl J Med 2006 · PMID 16495392 · DOI 10.1056/NEJMoa052771
Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease.. Manson JE et al.. N Engl J Med 2019 · PMID 30415629 · DOI 10.1056/NEJMoa1809944
Multivitamins in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial.. Sesso HD et al.. JAMA 2012 · PMID 23117775 · DOI 10.1001/jama.2012.14805
Multivitamin-multimineral supplementation and mortality: a meta-analysis of randomized controlled trials.. Macpherson H et al.. Am J Clin Nutr 2013 · PMID 23255568 · DOI 10.3945/ajcn.112.049304
Long-term multivitamin supplementation and cognitive function in men: a randomized trial.. Grodstein F et al.. Ann Intern Med 2013 · PMID 24490265 · DOI 10.7326/0003-4819-159-12-201312170-00006
Supplemental Vitamins and Minerals for CVD Prevention and Treatment.. Jenkins DJA et al.. J Am Coll Cardiol 2018 · PMID 29852980 · DOI 10.1016/j.jacc.2018.04.020
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
Multivitamins in the prevention of cancer and cardiovascular disease: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial.. Sesso HD et al.. Am J Clin Nutr 2022 · PMID 35294969 · DOI 10.1093/ajcn/nqac056
Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts.. Loftfield E et al.. JAMA Netw Open 2024 · PMID 38922615 · DOI 10.1001/jamanetworkopen.2024.18729
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
Selenium for preventing cancer.. Vinceti M et al.. Cochrane Database Syst Rev 2018 · PMID 29376219 · DOI 10.1002/14651858.CD005195.pub4
Subgroup analyses of the effectiveness of oral glucosamine for knee and hip osteoarthritis: a systematic review and individual patient data meta-analysis from the OA trial bank.. Runhaar J et al.. Ann Rheum Dis 2017 · PMID 28754801 · DOI 10.1136/annrheumdis-2017-211149
Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia.. Bhatt DL et al.. N Engl J Med 2019 · PMID 30415628 · DOI 10.1056/NEJMoa1812792
Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.. Abdelhamid AS et al.. Cochrane Database Syst Rev 2020 · PMID 32114706 · DOI 10.1002/14651858.CD003177.pub5
Enough is enough: Stop wasting money on vitamin and mineral supplements.. Guallar E et al.. Ann Intern Med 2013 · PMID 24490268 · DOI 10.7326/0003-4819-159-12-201312170-00011

← Back to overview

When popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A) were tested in large long-term placebo-controlled trials, most failed to deliver the promised prevention of disease.

Original statement

Translation

Origin

Scientific assessment

1. What was claimed?

2. What is demonstrably correct?

3. What is wrong or exaggerated?

4. What remains unclear?

5. Which studies support it?

6. Which studies contradict it?

7. What applies to Germany and Europe?

8. What is known about Egypt?

9. What practical conclusion is appropriate?

Assessment details

Scientific evidence in detail

What speaks for the claim?

USPSTF evidence review 2022

Antioxidant pills and death: Cochrane review

Daily multivitamin in older adults (COSMOS trial)

What speaks against the claim?

REDUCE-IT: prescription EPA

USPSTF evidence review 2022

What does the overall evidence say?

Which position is better supported?

Why some studies weigh more

Remaining uncertainty

Justified conclusion

Open questions

How deeply was this checked?

In plain language

Studies on this claim

Studies supporting the claim (17)

Low-dose omega-3 after heart attack

VITAL: fish oil in healthy adults

ASCEND: fish oil in diabetes

STRENGTH: high-dose omega-3

Glucosamine for knee pain (GAIT)

VITAL: vitamin D for prevention

PHS II: multivitamins and heart disease

Multivitamins and death – trials

Multivitamins and memory

Vitamins and heart disease – overview

USPSTF 2022: vitamins for prevention

USPSTF evidence review 2022

Daily multivitamin in older adults (COSMOS trial)

Multivitamins and death in 390,000 Americans

Antioxidant pills and death: Cochrane review

Selenium for preventing cancer: Cochrane review

Glucosamine for knee and hip arthritis

Studies contradicting or limiting the claim (1)

REDUCE-IT: prescription EPA

Studies with mixed or unclear results (2)

Cochrane: omega-3 and heart health

Editorial against supplements

Regional context

Germany / EU

Egypt

What applies in my country?

General scientific assessment

References