Minerals (especially taken in large doses) can cause side effects such as tooth staining, increased urination, stomach bleeding, uneven heart rate, confusion, and muscle weakness or limp feeling. Read the label of any multivitamin product you take to make sure you are aware of what it contains.
Vitamin and mineral supplementation is recommended for some people with certain conditions. Mayo Clinic says supplements may be appropriate for people who: Don't eat well or consume less than 1,600 calories a day. Are a vegan or a vegetarian who eats a limited variety of foods. Don't obtain two to three servings of fish a week.