Do I Need to Take More Vitamins
By supplementing the diet with additional vitamins and minerals, multivitamins can be a valuable tool for those with dietary imbalances or different nutritional needs [2]. People with dietary imbalances may include those on restrictive diets and those who can't or won't eat a nutritious diet. Pregnant women and elderly adults have different nutritional needs than other adults, and a multivitamin may be indicated by their physicians.
Precaucions
Some analyses have suggested that beta-carotene, vitamin A and vitamin E supplements, without adequate other redox antioxidants such as vitamin C, may shorten life rather than extend it[citation needed] in cases of oxidative stress (e.g. smokers), liver disease and liver stressing chemicals (e.g. statins). While multivitamins can be a valuable tool to correct dietary imbalances, it is worth exercising basic caution before taking them, especially if any medical conditions exist.
In particular, pregnant women should generally consult their doctors before taking any multivitamins. Because high doses of vitamin A are believed to cause birth defects, for example, special multivitamin formulations exist for pregnant women that do not contain this nutrient.
Severe vitamin and mineral deficiencies require medical treatment and can be very difficult to treat with common over-the-counter multivitamins. In such situations, special vitamin or mineral forms with much higher potencies are available, either as individual components or as specialized formulations, sometimes requiring a prescription.
Multivitamins may be dangerous if taken in large amounts, due to the toxicity of certain components, principally iron. In particular, other components at extraordinary levels in high potency forms include (but are not limited to) vitamin A, vitamin D, vitamin B6, time release niacin, and potassium. Total iron content of the whole bottle is the primary concern for child safety. There also are strict limits on the retinol content for vitamin A during pregnancies that are specifically addressed by prenatal formulas. Additionally, various medical conditions and medications may adversely interact with multivitamins.