One-a-day multivitamins are composed of the U.S. Department of Agriculture's daily-recommended amounts of vitamins and minerals necessary for optimal human health. The varieties and combinations of one-a-day vitamins available on the market boggle the mind. Consumers armed with the facts on the types of multivitamins, contents, benefits and their side effects can make an informed and healthier choice.
Many manufacturers produce vitamin supplements called “One-A-Day” that claim to have 100 percent or more of the USDA’s RDA of essential vitamins. Multivitamin products vary in their content and it is up to the consumer to consult the product label for the specific vitamin combinations.
The one-a-day multivitamin category has subtypes, such as one-a-day stress multivitamins with extra quantities of B vitamins, antioxidant combinations, mineral combinations and even some without minerals, according to the International Bibliographic Information on Dietary Supplements, also referred to as IBIDS. The IBIDS found 1,246 different brands of one-a-day vitamins with a variety of combinations.
One-a-day multivitamin use is especially helpful for people with specific vitamin deficiencies who cannot get the proper amount of vitamins in their diet. Women’s nutritional needs change as they age. Multivitamin supplements that contain extra calcium, vitamin D, zinc, vitamins B, C, A and E have shown beneficial results in women during menopause, premenstrual syndrome and at various stages of their life, according to the June 2007 issue of “Pharmacy Times.”
Pregnant and breastfeeding women can benefit from the extra iron in multivitamins. A double-blind controlled study by A.E. Czeizel published in the March 1996 issue of the “American Journal of Medical Genetics” studied the preventive effects of multivitamin supplementation on pregnant women. The study found multivitamin use by pregnant women significantly reduced the number of urinary tract abnormalities, obstructive defects and the number of cardiovascular malformations.
Nutritional experts disagree on whether one-a-day vitamins are necessary for children. Many foods made for children such as breakfast cereals, juices, milk and other common snacks are fortified with vitamins and minerals. Consult your pediatrician or other health care provider if you are concerned about your child getting the proper amount of vitamins and minerals. Some children at risk for vitamin deficiencies include children with eating disorders, those who do not get a balanced diet, have chronic diseases or are on a vegan diet.
Taking a multivitamin is not a replacement for eating a well balanced diet. The rated amounts of the different vitamins in a one-a-day formula are not what the body may actually absorb. The amount the body absorbs of these nutrients is called bioavailability. Each vitamin in a multivitamin has a different bioavailability according to many factors including the form of the multivitamin, other chemicals included with the vitamin, concentration of raw food particles that may bind to some nutrients and intestinal transit time, according to the National Institutes of Health.
Certain vitamins and minerals can interact with medications or physical conditions. Megadoses of vitamins and minerals can be toxic to children and adults. Different prescription drugs can also have interactions with vitamins and minerals. Always consult your physician or health care provider before taking a one-a-day vitamin.
- International Bibliographic Information on Dietary Supplements: Allowing for Variations in Multivitamin Supplement Composition Improves Nutrient Intake Estimates for Epidemiologic Studies
- National Institutes of Health: Reduction of Urinary Tract and Cardiovascular Defects by Periconceptional Multivitamin Supplementation
- Pharmacy Times: Multivitamin Supplements for Women
- National Institutes of Health: Executive Summary - Multivitamin/Mineral Supplements and Prevention of Chronic Disease