Supplements usually are not necessary for most healthy people who are willing and able to eat a balanced and varied diet. However, under certain circumstances, some healthy people may benefit from supplements:
Women with heavy menstrual bleeding may need an iron supplement to replace iron from blood loss.
Women who are pregnant or breast-feeding need more of some nutrients, especially iron, folic acid, and calcium.
Menopausal women might benefit from calcium supplements.
People on very-low-calorie diets may not consume enough food to meet all their nutrient needs.
Some vegetarians may need extra calcium, iron, zinc, and vitamins B12 and D.
People with limited milk intake and sunlight exposure may be advised to take a vitamin D supplement.
Some babies may need a fluoride supplement and perhaps iron or vitamin D.