In general, children and adults might benefit from taking one multiple vitamin per day. For a few pennies per day, a multivitamin provides added insurance that people are getting adequate intake of necessary vitamins and micronutrients. To avoid indigestion, take the multivitamin with food.
Women may need extra calcium and iron. You can get calcium from low fat dairy products and from over-the-counter calcium in the form of calcium carbonate and calcium citrate. These are inexpensive and easy to take. Calcium supplements are best absorbed when taken with meals, at a dose of 500 mg one or two times per day. Women who bleed excessively during menstruation may need to take a multivitamin and mineral supplement that contains iron to meet the daily recommendation of 15 mg. Pregnant and lactating women are usually given supplements by their doctors to meet their increased needs for iron and other nutrient.
Women of childbearing age who may become pregnant should take a folic acid supplement for one year prior to conception. A recent study suggests that women who took folic acid for one year prior to pregnancy reduced their risk of delivering a premature baby by 50 to 70 percent. Because pregnancy is often not planned, ideally you should start taking folic acid when you become sexually active. A standard multiple vitamin contains a sufficient amount of folic acid, 400 micrograms.
Teenagers often have irregular eating habits and may not eat a balanced diet. A multivitamin with minerals can help fill in the nutritional gaps. Some teenage girls also need a daily calcium supplement.
Vegetarians are advised to take a multivitamin with iron and other minerals each day. Iron and B12 deficiency occur frequently in strict vegetarians.
Dieters and people who avoid entire food groups are more likely to have vitamin and mineral deficiencies. A daily generic multivitamin with minerals should be considered.
People with deficiency diseases or absorption disorders may need therapeutic doses of nutrients (two to 10 times the Recommended Dietary Intake) prescribed by a doctor. People taking prescription medications that interfere with the absorption of nutrients may also need higher dose supplements, as will those who abuse alcohol or drugs.