Avoid taking more than one multivitamin product at the same time, unless your doctor tells you to. Taking similar vitamin products together can lead to an overdose of vitamins or serious side effects. Many multivitamin products also contain minerals such as calcium, iron, magnesium, potassium, and zinc. Never take more than the recommended dose of a multivitamin.
If you decide to take a multivitamin, make sure you choose a reputable brand and don't consume more than one serving per day. Other drugs can affect multivitamins, including prescription and over-the-counter medicines, vitamins, and herbal products. Certain minerals contained in a multivitamin can also cause serious overdose symptoms if taken in excess. However, megadoses of nutrients can still be dangerous, so you should only consume a multivitamin that doesn't include more than 100 percent of the recommended daily allowance for each nutrient.
While there is no clear consensus on whether the nutrients in multivitamin supplements are beneficial, many experts agree that high doses of vitamins could pose health risks. Multivitamins are also used to treat vitamin deficiencies (lack of vitamins) caused by illness, pregnancy, poor nutrition, digestive disorders, and many other conditions. This can be a key difference in how multivitamins react with the body compared to the nutrients in whole foods. In addition to fiber, each of these nutrients is included in a typical multivitamin supplement, in amounts that are adjusted to daily needs.
Multivitamins are a combination of many different vitamins that are normally found in food and other natural sources. Colorado State University notes that some people may benefit more from taking a multivitamin supplement, due to possible deficiencies or an increased need for certain vitamins. Do not take multivitamins with milk, other dairy products, calcium supplements, or antacids that contain calcium. Vitamins with Extra C, Surbex-T, Theragran, Superplex-T, Vi-Stress, cod liver oil, peppermint, animal-shaped vitamins, B-50 complex, B-50 complex, vitamin B 100 complex, B-Stress, B-scorbic, bee with C, chewable multivitamins for children, balanced B-50, balanced B-150, Unicap capsule, Unicap Jr.
Scientists reviewed several clinical trials conducted on more than 400,000 participants and concluded that multivitamins have no effect on the risk of cancer, heart disease, or premature death. Taking two multivitamins a day can affect your long-term health; these products are not intended to replace a balanced diet.