A vitamin and mineral supplement provides a variety of nutrients that are also found in food. These supplements are often called multivitamins. They come in the form of pills, chewable tablets, powders, and liquids.
A standard multivitamin usually contains:
- Water-soluble vitamins. These vitamins pass in and out of the body easily. Most do not build up in the body's cells. Water-soluble vitamins include vitamin C and the B vitamins: thiamine, riboflavin, niacin, pantothenic acid, B6, biotin, folic acid, and B12.
- Fat-soluble vitamins. These vitamins are stored in the body's cells and do not pass out of the body as easily as water-soluble vitamins do. Fat-soluble vitamins include vitamins A, D, E, and K.
- Minerals. These include calcium, copper, iron, magnesium, phosphorus, potassium, selenium, and zinc.
Some multivitamins also contain other ingredients that aren't vitamins or minerals. These include substances such as the antioxidants lutein and lycopene.
Why take a supplement?
The best way to get the vitamins and minerals you need is by eating a wide variety of healthy foods. The Dietary Guidelines for Americans recommend fruits, vegetables, whole grains, milk and milk products, and seafood as part of a nutritious food plan. A supplement can't make up for unhealthy eating habits. But sometimes even people who have healthy eating habits find it hard to get all the fruits, vegetables, and other healthy foods they need. A supplement can help fill in the gaps.
Certain people are more likely to need a supplement. They include:
- People who eat a calorie-restricted diet, which does not provide enough vitamins and minerals.
- Women who are pregnant or breastfeeding.
- People who are sick, injured, or recovering from surgery.
- Infants, especially to be sure they are getting adequate amounts of calcium and vitamin D.
- People who can't or don't eat a variety of foods, such as people who have food allergies or people who eat a vegetarian diet.
What about supplements that are labeled for certain people (such as women or seniors)?
Many supplements are advertised as being specially designed for men or for women or for certain age groups. A standard multivitamin is okay for most people who take a supplement. But some people prefer to take a supplement that is made for their gender or age group.
Types of specialized supplements include:
- Women's formulas. Women's supplements have extra iron. This is because women who are still having periods need more iron than men do. But after menopause, women's iron needs are the same as men's. Some women's formulas also contain extra calcium, since women are more likely than men to get osteoporosis.
- Men's formulas. These are lower in iron, because men need less iron than women.
- Senior formulas. These are made for older adults and usually have less iron and vitamin K and more vitamin B12 and vitamin D.
- Prenatal formulas. These are made for women who are pregnant, are planning to get pregnant, or are breastfeeding. The supplements have extra folic acid and iron. Folic acid is especially important because it can help prevent certain birth defects, especially neural tube defects. Sometimes these supplements also have more calcium.
What should you look for when you pick a supplement?
- Choose one that provides a variety of vitamins and minerals (a multivitamin) rather than a supplement that provides only a single vitamin or mineral (unless your doctor has recommended that you take an individual vitamin or mineral).
- Pick one that, along with the foods you eat, provides the Recommended Dietary Allowance (RDA) for each vitamin and mineral. Supplements that provide a lot more than the RDA can cause health problems. This is especially important for minerals and the fat-soluble vitamins A, D, E, and K. These are stored more easily in the body, and they can build up to dangerous levels.
- Check the expiration date. Do not buy supplements that have expired or that will expire before you can finish the bottle.
- If the supplement has the United States Pharmacopeia (USP) seal, the supplement has been tested and contains the amounts of vitamins and minerals that are listed on the label.
- Check the label for other ingredients. Some supplements may contain food ingredients, such as wheat, corn, eggs, or gelatin. If you have a food allergy or are sensitive to these foods, look for supplements that don't have those ingredients.
What should you watch out for?
When you think about buying a dietary supplement, be sure to check the claims that the manufacturers make. The U.S. Food and Drug Administration (FDA) does not regulate dietary supplements in the same way that it regulates medicines. This means that supplements can be sold without research on how well, or even if, they work.
Here are some things to consider:
- A generic brand (or store brand) often works just as well as a name brand supplement. Look for generic brands that contain the same amount of vitamins and minerals as the name brand.
- Most man-made (synthetic) vitamins are as good as natural vitamins.
- No supplement has been proved to cure diseases such as cancer, diabetes, heart disease, or digestive problems. If it sounds too good to be true, it probably is. Be cautious of supplements that promise quick and dramatic results.
Other Works Consulted
- American Dietetic Association (ADA) (2009). Position of the American Dietetic Association: Nutrient supplementation. Journal of the American Dietetic Association, 109(12): 2074–2085. Available online: http://www.eatright.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=8445.
- Gallagher ML (2012). Intake: The nutrients and their metabolism. In LK Mahan et al., eds., Krause's Food and the Nutrition Care Process, 13th ed., pp. 32–128. St. Louis: Saunders.
- U.S. Food and Drug Administration (2008). FDA 101: Dietary Supplements. Available online: http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm050803.htm.
- U.S. Food and Drug Administration (2009). Fortify Your Knowledge About Vitamins. Available online: http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm118079.htm.
Current as of: August 22, 2019
Author: Healthwise Staff
Medical Review: Kathleen Romito, MD - Family Medicine
Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator