cPeople take multivitamins on their own or under healthcare guidance for a variety of reasons, such as to treat vitamin deficiencies, promote wellness, and lower the risk of disease.
Multivitamins generally contain three categories of nutrients:
- Water-soluble vitamins. These can dissolve in water and don’t usually accumulate in the body nor cause severe side effects if you take them in excess (e.g., B vitamins, vitamin C).
- Fat-soluble vitamins. These dissolve in fat and accumulate in the body, reaching toxic levels and potentially causing havoc if you take them in excess (e.g., vitamins A, D, E, and K).
- Minerals. These are inorganic elements that can accumulate in the body and sometimes cause harmful effects if you take them in excess (e.g., iron, iodine, zinc, copper, and selenium).
Side effects of multivitamins
When taken as directed, multivitamins are not expected to cause serious side effects. Common side effects may include:
- upset stomach
- unusual or unpleasant taste in your mouth
- Dark stools
- Abdominal pain
- Avoid taking more than one multivitamin product at the same time unless your doctor tells you to. Taking similar vitamin products together can result in a vitamin overdose or serious side effects.
- Avoid the regular use of salt substitutes in your diet if your multivitamin contains potassium. If you are on a low-salt diet, ask your doctor before taking a vitamin or mineral supplement.
- Do not take multivitamins with milk, other dairy products, calcium supplements, or antacids that contain calcium. Calcium may make it harder for your body to absorb certain ingredients of the multivitamin.