Under what circumstances should I take vitamin supplements?

Kelly Traver
Internal Medicine

A few circumstances in which you might want to consider taking a supplement are as given below:

  • If you are a menstruating woman, particularly with a heavy flow, or if your diet is light in iron, you may want to supplement with an iron pill.
  • If you don't eat many dairy products, you should supplement with calcium. Postmenopausal women should also supplement with calcium as well as vitamin D to protect against osteoporosis. The recommended dose is calcium, 1,200 milligrams per day, and vitamin D, 800 IU per day. Remember, though, that the most important proactive measure for osteoporosis is a regular exercise routine that involves weight-bearing activities.
  • Recent studies demonstrate a link between low vitamin D levels and an increase in overall mortality. Vitamin D appears to offer a protective effect against cancer, although its exact mechanism of action is not known. Low vitamin D levels have also been associated with an increased risk of heart attacks. Vitamin D is toxic at high doses, but it appears that a large number of people have lower-than-normal vitamin D levels. It is thought that perhaps this is because more people are avoiding the sun, since vitamin D is made from a precursor in the skin that is activated by the sun.
  • The most frequently recommended supplement today is omega-3 fatty acids, which improve triglyceride and HDL levels, decrease inflammation, and appear to decrease blood pressure. They also increase BDNF and so appear to be beneficial to memory and mood.
  • If you are pregnant or trying to get pregnant, you should take prenatal vitamins including folic acid, which helps prevent neural tube birth defects.
  • If you are breast-feeding, you may also want to take more iron, folic acid, and calcium.
  • If you are a vegetarian, you may need extra vitamin B12, as this is found only in animal products. You may also need extra calcium, zinc, iron, and vitamin D (800 IU daily) if your eating preferences do not include any meat, dairy, or other animal products.

Supplements are useful for people who cannot meet their nutrient needs through a regular, varied diet. According to the Academy of Nutrition and Dietetics, among those who may benefit from taking a dietary supplement are:

  • Women of childbearing age who may become pregnant, as they need to consume adequate amounts of folic acid to prevent certain birth defects
  • Pregnant and lactating women who can’t meet their nutrient needs with food
  • Older individuals, who need adequate amounts of vitamin D and synthetic vitamin B12
  • Individuals who do not drink enough milk and/or do not have adequate sun exposure to meet their vitamin D needs
  • Individuals on low-calorie diets that limit the amount of vitamins and minerals they can consume through food
  • Strict vegetarians, who have limited dietary options for vitamins B12 and D and other nutrients
  • Individuals with food allergies or lactose intolerance that limit food choices
  • Individuals who abuse alcohol, have a poor appetite, have medical conditions such as intestinal disorders, or are taking medications that may increase their need of certain vitamins
  • Individuals who are food insecure and those who are eliminating food groups from their diet
  • Infants who are breast-fed should receive 400 IU of vitamin D daily until they are consuming at least 1 quart of formula daily. Children age one and older should receive 400 IU of vitamin D daily if they consume less than one quart of milk per day. Adolescents who consume less than 400 IU of vitamin D daily from their diet would also benefit from a supplement.

You should always meet with a registered dietitian (RD) before taking a supplement to make sure that it is appropriate for you based on your diet and medical history. You can find an RD in your area at:

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.