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Vitamins and Minerals


Vitamins and minerals are essential substances that our bodies need to function normally. The known vitamins are vitamins A, C, D, E, and K and the B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), cobalamin (B12), biotin, and folate/folic acid. A number of minerals are essential for health, including calcium, phosphorus, potassium, sodium, chloride, magnesium, iron, zinc, iodine, sulfur, cobalt, copper, fluoride, manganese, and selenium.  

  • The Dietary Guidelines for Americans 2020–2025 recommends that people should aim to meet their nutritional requirements through a healthy eating pattern that includes nutrient-dense foods. In addition to vitamins and minerals, foods provide other important components beneficial to health, such as fiber. The guidelines provide recommendations for specific populations, including women who are or may become pregnant, women who breastfeed, and people ages 60 and over.  
  • Some people who don’t get enough vitamins and minerals from food alone, including people who are on low-calorie diets or who avoid certain foods (such as strict vegetarians or vegans), may want to consider taking a vitamin and mineral supplement. Health care providers may recommend supplements for people with certain medical conditions.  


  • If you consume fortified foods and beverages (such as cereals or drinks with added vitamins and minerals) along with dietary supplements, you should make sure that your total intake of vitamins and minerals is not more than the safe upper limits for any nutrients. You can find information about the safe upper limits on specific nutrients from the NIH Office of Dietary Supplements Dietary Supplement Fact Sheets.  
  • Taking excess amounts of vitamin A (preformed retinol form, not beta-carotene) during pregnancy has been shown to increase the risk of birth defects. 
  • Women of childbearing age, pregnant women, infants, young children, and teenage girls are at risk of obtaining insufficient amounts of iron from their diets. Iron supplements are a leading cause of poisoning in young children, so they should be kept out of children’s reach. 

What does the science say about multivitamin/multimineral supplements?

Multivitamins/multiminerals (MVMs) are popular dietary supplements taken by approximately one-third of adults and one-quarter of children and adolescents in the United States. MVMs cannot take the place of eating a variety of foods that are important to a healthy diet.  

Taking a daily dose of a basic MVM is unlikely to pose a health risk for healthy people. However, taking them at high doses or taking many different supplements may cause adverse side effects. 

  • The effects of MVMs on the risk of health problems are hard to study because products vary and because people with healthier lifestyles are more likely to take MVMs. 
  • Most studies have shown little or no effect of MVMs on the risk of health problems. 
  • There’s no standard or regulatory definition for what nutrients MVMs, or any dietary supplement, must contain or at what levels. Manufacturers choose which vitamins, minerals, and other ingredients, as well as the amounts, to include in their products. However, MVMs are required to provide nutrition information on a Supplement Facts panel and list all ingredients on the product label (ingredients not in the Supplement Facts panel must be listed under “Other Ingredients”). 
  • MVMs providing nutrients at or up to 100 percent of the Daily Value (DV) do not typically interact with medications. However, if you take a blood thinner, such as warfarin (Coumadin and other brand names), talk to your health care provider before taking any MVM or other dietary supplement that contains vitamin K
  • Smokers, and possibly former smokers, should avoid MVM products that provide large amounts of vitamin A (as preformed retinol or beta-carotene or some combination of the two). A few studies have linked high supplemental doses of these nutrients with an increased risk of lung cancer in smokers. 
  • The National Institutes of Health sponsored the Age-Related Eye Disease Study (AREDS), which showed that a dietary supplement formulation containing high doses of vitamins C and E, beta-carotene, zinc, and copper can help slow the progression to advanced age-related macular degeneration (AMD). A second study, AREDS2, showed that removing beta-carotene from the AREDS formulation didn’t lessen its protective effect against developing advanced AMD. AREDS2 also showed that adding omega-3 fatty acids did not improve the effectiveness of the formulation. 

What does the science say about taking vitamins and minerals to prevent or treat COVID-19?

There is not enough scientific evidence to clearly show that taking any dietary supplement helps to prevent or cure COVID-19. The NIH Office of Dietary Supplements has detailed information (in English and Spanish) about specific dietary supplements and COVID-19. 

For More Information

NCCIH Clearinghouse

The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.

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Office of Dietary Supplements (ODS), National Institutes of Health (NIH)

ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need To Know) and fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements).

Multivitamin/Mineral Supplements


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Know the Science

NCCIH and the National Institutes of Health (NIH) provide tools to help you understand the basics and terminology of scientific research so you can make well-informed decisions about your health. Know the Science features a variety of materials, including interactive modules, quizzes, and videos, as well as links to informative content from Federal resources designed to help consumers make sense of health information.

Explaining How Research Works (NIH)

Know the Science: How To Make Sense of a Scientific Journal Article

Understanding Clinical Studies (NIH)


A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.


This publication is not copyrighted and is in the public domain. Duplication is encouraged.

NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.

Last Updated: July 2023