DoubleChecks

What was claimed

Multivitamin supplements make people far less likely to suffer a wide variety of mental and physical health issues (Vitamin A prevents measles)

Our verdict

Inaccurate

Vitamin A supplementation reduces measles severity, complications, and mortality and is recommended as part of measles treatment, but it does not reliably prevent measles infection itself. High-quality trials and reviews show little or inconsistent benefit of routine multivitamin use for preventing most chronic diseases or mental health disorders in well-nourished populations. Benefits are clearer for correcting deficiencies or in specific groups (pregnant people, children in low-resource settings), so the blanket statement overstates the evidence.

2 of 3 AI systems agree20 sources citedChecked Aug 11, 2026

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Key findings

Vitamin A prevents measles.

Incorrect95%
2 of 3 AIs agree·Perplexity: Misleading

Multivitamin supplements make people far less likely to suffer a wide variety of mental and physical health issues.

Misleading86%
2 of 3 AIs agree·Perplexity: Incorrect

Verified against 20 sources

ods.od.nih.govhopkinsmedicine.orgwebmd.comhealth.harvard.eduwebmd.comosfhealthcare.orggoodrx.compmc.ncbi.nlm.nih.govhealthline.comhealth.clevelandclinic.orgnewchapter.comwebmd.compharmeasy.inhoustonmethodist.orgjamanetwork.comlpi.oregonstate.eduhealth.harvard.eduharmonyhealthcareli.orgnaturemade.comnutritionsource.hsph.harvard.edu

Detailed Analysis

The response makes a broad claim that multivitamins make people far less likely to suffer many mental and physical health problems, but major reviews say multivitamins do not reduce the risk of chronic disease and have little or no proven preventive benefit for most healthy adults. The separate Vitamin A claim is also wrong as written: vitamin A helps prevent measles complications mainly in deficient children, but it does not universally 'prevent measles.'

Why this verdict

  • The response makes a broad claim that multivitamins make people far less likely to suffer many mental and physical health problems, but major reviews say multivitamins do not reduce the risk of chronic disease and have little or no proven preventive benefit for most healthy adults.
  • The separate Vitamin A claim is also wrong as written: vitamin A helps prevent measles complications mainly in deficient children, but it does not universally 'prevent measles.'

Claims checked

Multivitamin supplements make people far less likely to suffer a wide variety of mental and physical health issues.

Incorrect98%
NIH and major clinical reviews report no reduction in risk for chronic disease, heart disease, cancer, cognitive decline, or death for most people. The claim overstates the evidence and is not supported by the sources.

This claim may mislead readers without added context.

Vitamin A prevents measles.

Misleading93%
Vitamin A is used to treat measles and reduce severity and complications, especially in children with deficiency. It does not prevent measles infection in the general sense.

This claim may mislead readers without added context.

What other AI think

The claim contains a significant factual error about vitamin A preventing measles, which is demonstrably false according to medical authorities. The first part about multivitamins is also overstated—evidence shows they don't reduce major health risks in well-nourished populations, contradicting the "far less likely" claim.

Why this verdict

  • The claim contains a significant factual error about vitamin A preventing measles, which is demonstrably false according to medical authorities.
  • The first part about multivitamins is also overstated—evidence shows they don't reduce major health risks in well-nourished populations, contradicting the "far less likely" claim.

Claims checked

Vitamin A prevents measles

Incorrect99%
Multiple authoritative sources confirm vitamin A does not prevent measles. It can only reduce severity after infection occurs. The MMR vaccine is the only effective prevention method.

This claim may mislead readers without added context.

Multivitamin supplements make people far less likely to suffer a wide variety of mental and physical health issues

Misleading92%
Evidence shows multivitamins do not reduce cardiovascular events, mortality, or cancer risk in generally nourished adults. Some cognitive benefits exist, but the claim overstates the breadth and magnitude of protective effects.

This claim may mislead readers without added context.

The response mixes an overbroad, unsupported generalization with a partially incorrect specific statement. Evidence does not support that multivitamins broadly and substantially lower risk for many mental and physical illnesses in well-nourished adults. Vitamin A does reduce measles severity and mortality, but it does not reliably prevent infection.

Why this verdict

  • The response mixes an overbroad, unsupported generalization with a partially incorrect specific statement.
  • Evidence does not support that multivitamins broadly and substantially lower risk for many mental and physical illnesses in well-nourished adults.
  • Vitamin A does reduce measles severity and mortality, but it does not reliably prevent infection.

Claims checked

Vitamin A prevents measles

Incorrect90%
Vitamin A supplementation reduces measles severity, complications, and mortality and is recommended as part of measles treatment, but it does not reliably prevent measles infection itself.

This claim may mislead readers without added context.

Multivitamin supplements make people far less likely to suffer a wide variety of mental and physical health issues

Misleading80%
High-quality trials and reviews show little or inconsistent benefit of routine multivitamin use for preventing most chronic diseases or mental health disorders in well-nourished populations. Benefits are clearer for correcting deficiencies or in specific groups (pregnant people, children in low-resource settings), so the blanket statement overstates the evidence.

This claim may mislead readers without added context.

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