Multivitamin safety
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Multivitamin Safety: General Population and Dosage Considerations
Multivitamin and mineral supplements are widely used by people of all ages, often with the belief that they are inherently safe. Research shows that when multivitamins are taken within recommended daily allowances, they are generally safe for long-term use in healthy adults, pregnant women, and the elderly, with only minor side effects such as mild gastrointestinal discomfort reported in some cases. There is no evidence that standard multivitamin use increases mortality or causes significant harm when used as directed, even over periods longer than 10 years 347.
High-Dose Supplement Risks and Specific Nutrient Concerns
While standard multivitamin use is considered safe, taking high doses of certain vitamins—especially fat-soluble ones like vitamins A, D, and E, as well as some water-soluble vitamins like folic acid—can be harmful. High doses may lead to adverse health effects, and the long-term consequences of excessive vitamin intake are not fully understood. Therefore, it is not recommended to take high-dose vitamin supplements unless specifically advised by a healthcare provider 16.
Elemental Impurities and Toxicity in Multivitamin Supplements
Concerns about toxic elements such as arsenic, cadmium, mercury, and lead in multivitamin supplements have been addressed in recent studies. Analyses of both adult and children's multivitamin products found that the levels of these toxic elements are generally well below established safety limits. The risk of both non-cancer and cancer outcomes from these impurities is considered very low, indicating that current products on the market are safe for consumption when used as directed 510.
Multivitamin Safety in Special Populations
For pregnant women, multivitamin use is often recommended to improve birth outcomes and reduce the risk of certain birth defects. Studies in high-income countries show that multivitamin use does not increase the risk of adverse birth outcomes and may even reduce the risk of some congenital anomalies. However, the quality of evidence is sometimes low, and more research is needed to confirm these findings .
Multivitamin Use and Mortality
Large cohort studies suggest that multivitamin use may be associated with a small reduction in overall mortality, particularly due to lower cardiovascular disease risk. However, after adjusting for other health and lifestyle factors, the effect is modest, and multivitamin use does not appear to increase mortality risk .
Conclusion
Multivitamin supplements are generally safe for most people when taken within recommended daily limits. High doses of certain vitamins can be harmful, so it is important to avoid exceeding recommended amounts. The risk from toxic elements in commercially available multivitamins is very low. For most healthy adults and children, as well as pregnant women, multivitamin use is safe and does not increase the risk of serious health problems. However, individuals should consult healthcare professionals before starting high-dose supplements or if they have specific health concerns.
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