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
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
- 25 October 2026 provisional
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 (12)
-
Low-dose omega-3 after heart attack
Kromhout D et al.. N Engl J Med 2010 · PMID 20929341 · DOI 10.1056/NEJMoa1003603Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
VITAL: fish oil in healthy adults
Manson JE et al.. N Engl J Med 2019 · PMID 30415637 · DOI 10.1056/NEJMoa1811403Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
ASCEND: fish oil in diabetes
ASCEND Study Collaborative Group et al.. N Engl J Med 2018 · PMID 30146932 · DOI 10.1056/NEJMoa1804989Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
STRENGTH: high-dose omega-3
Nicholls SJ et al.. JAMA 2020 · PMID 33190147 · DOI 10.1001/jama.2020.22258Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
Glucosamine for knee pain (GAIT)
Clegg DO et al.. N Engl J Med 2006 · PMID 16495392 · DOI 10.1056/NEJMoa052771Randomised controlled trialcited by the Tayebat archiveabstract only checkedNot 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.
-
VITAL: vitamin D for prevention
Manson JE et al.. N Engl J Med 2019 · PMID 30415629 · DOI 10.1056/NEJMoa1809944Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
PHS II: multivitamins and heart disease
Sesso HD et al.. JAMA 2012 · PMID 23117775 · DOI 10.1001/jama.2012.14805Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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?
- Do the results apply to Germany and Europe?
Applicable.
-
Multivitamins and death – trials
Macpherson H et al.. Am J Clin Nutr 2013 · PMID 23255568 · DOI 10.3945/ajcn.112.049304Meta-analysiscited by the Tayebat archiveabstract only checkedNo 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.
-
Multivitamins and memory
Grodstein F et al.. Ann Intern Med 2013 · PMID 24490265 · DOI 10.7326/0003-4819-159-12-201312170-00006Randomised controlled trialcited by the Tayebat archiveabstract only checkedNo 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.
-
Vitamins and heart disease – overview
Jenkins DJA et al.. J Am Coll Cardiol 2018 · PMID 29852980 · DOI 10.1016/j.jacc.2018.04.020Meta-analysiscited by the Tayebat archiveabstract only checkedMostly 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.
-
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 only 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 only 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.
No study in this group is marked as key.
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/NEJMoa1812792Randomised controlled trialindependent cross-checkabstract only checkedHigh-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.
No study in this group is marked as key.
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.pub5Meta-analysiscited by the Tayebat archiveabstract only checkedLittle 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.
-
Editorial against supplements
Guallar E et al.. Ann Intern Med 2013 · PMID 24490268 · DOI 10.7326/0003-4819-159-12-201312170-00011Othercited by the Tayebat archiveabstract only checkedOpinion; 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.
No study in this group is marked as key.
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
- 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