Multivitamins can play a positive role in your health if you're deficient in vitamins, but there is a risk of toxicity if you consume too much. It's best to meet with your doctor to test your vitamin and mineral levels and to ask if you need a multivitamin or individual vitamin or mineral supplements to prevent or treat specific deficiencies. In 2010, the U.S. Department of Agriculture labeled potassium, calcium and vitamin D "nutrients of concern" for Americans because their daily intake of them from foods is lower than recommended. Iron, folate and vitamin B12 are nutrients of concern for pregnant women.
Multivitamins Boost Your Vitamin Levels
A study published in "Public Health Nutrition" in 2001 found that taking a multivitamin does increase your body's vitamin content to acceptable levels. Vitamin deficient patients became no longer deficient after taking the multivitamin for just 7 days. This was particularly noticed in the case of women deficient in iron and folate and men deficient in vitamin A. In 2013, a meta-analysis of clinical studies on the correlation between multivitamin consumption and mortality was published in the "American Journal of Clinical Nutrition." All studies examined found no association between multivitamin treatment and mortality rate, suggesting that taking them may not protect you from fatal diseases.
According to the Food and Drug Administration, multivitamins can be harmful to your health and even life-threatening. They can interact with medications -- both prescription and over-the-counter drugs -- so consult with your doctor before taking a multivitamin. Certain vitamins -- particularly fat-soluble vitamins -- can cause toxicity when taken in higher doses than needed, whether through multivitamins or multivitamins combined with fortified foods. To be safe, do not take any more vitamins than prescribed by your doctor or recommended on the product label. Upper limits for some vitamins and minerals are not established, so it's always safer to take multivitamins with medical supervision.