A Beginner’s Guide to Multivitamins

Multivitamins are among the most widely used dietary supplements. They combine a range of vitamins, and usually minerals, in a single daily tablet or capsule. They are simple to take, but it helps to know what they can and cannot do before deciding whether one belongs in your routine.

What is a multivitamin?

According to the NIH Office of Dietary Supplements, multivitamin/mineral supplements contain a combination of vitamins and minerals, and sometimes other ingredients. No regulation defines which nutrients they must contain or in what amounts. Manufacturers choose the formula, so two products with similar names can be quite different.

Common types

• Basic once-daily products provide amounts close to recommended daily intakes.
• Targeted formulas are designed for groups such as women, men, older adults or pregnancy.
• High-potency products contain some nutrients well above recommended amounts.

Why people take them

Most people take a multivitamin to increase their nutrient intake or as general nutritional insurance. They can raise intake of nutrients that some diets lack, such as vitamin D, calcium or folic acid.

What the research shows

Studies have not consistently shown that multivitamins reduce the risk of long-term diseases such as heart disease or cancer in the general population. They should not be expected to prevent or treat illness. Their role is nutritional: helping people meet recommended intakes when food alone falls short.

Who might benefit

The NIH notes that certain groups may benefit from specific nutrients:

• people who could become pregnant need 400 micrograms of folic acid a day from supplements or fortified foods;
• pregnant people often need extra iron and folic acid, usually from a prenatal supplement;
• adults over 50 may need vitamin B12 from fortified foods or supplements;
• people with restricted diets, poor appetite or conditions that affect absorption.

Safety points

A basic multivitamin taken as directed is unlikely to cause harm for most healthy people. Problems arise mainly from combining products.

• Adding up: a multivitamin plus single-nutrient supplements plus fortified foods can push intake above upper limits.
• Vitamin A and beta-carotene: people who smoke, or used to, should avoid products with large amounts. Too much preformed vitamin A in pregnancy can harm the baby.
• Iron: adult men and postmenopausal women should generally avoid products providing 18 mg or more of iron unless a doctor advises otherwise. Iron supplements are dangerous to young children in overdose, so store them securely.
• Vitamin K: can reduce the effect of the blood thinner warfarin.

How to take one

• Follow the serving size on the label; more is not better.
• Take it with a meal, which improves absorption of fat-soluble vitamins and is gentler on the stomach.
• Take it at the same time each day so it becomes a habit.

Our Daily Multivitamin is a once-daily tablet for adults.

Talk to a professional first if you

• are pregnant or breastfeeding;
• take prescription medicines;
• have a medical condition;
• are choosing a supplement for a child.

The bottom line

A multivitamin is a convenience, not a cure. It can cover small gaps, provided you choose a sensible formula and keep eating well. See the options in our vitamins and nutrition range.

Sources

1. NIH Office of Dietary Supplements. Multivitamin/mineral Supplements.
2. NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know.
3. U.S. Food and Drug Administration. Information for Consumers on Using Dietary Supplements.