Vitamin supplements good for health?

Dear Alice:

Almost every place that I go to, I see stores and stores just devoted to selling vitamins and more vitamins, and I was wondering what the benefits are of a normal healthy person taking vitamins daily. Are there any risks for a normal healthy person who doesn't take vitamins? Will the person taking vitamins' health be improved or have longer longevity? Will the person not taking any vitamins be as healthy as the person who is taking them? And also, what will happen if a person takes more than he or she should consume every day?

Health Enthusiast

Dear Health Enthusiast,

As you wrote, vitamins are ubiquitous these days. While many American adults do take at least one supplement daily, vitamins aren't necessarily recommended for everyone. Vitamin supplements are meant to be just that — a supplement to a healthy diet for those needing more vitamins. They're not meant to be a replacement for a healthy diet. For people without nutrient deficiencies or certain health conditions, a balanced and varied diet provides enough vitamin-rich food for the body without risking anything by passing on the supplements. Some claims made by companies selling vitamins may sound too good to be true, and (surprise!) scientific research has found that these products often don't do what they claim. While certain groups do benefit from taking vitamin supplements (which usually involves a recommendation from their health care provider) others are likely fine getting vitamins from the best source of all — nutritious foods.

How do you know if you're eating a balanced, varied diet that provides the vitamins you need? Your first stop might be to check out the Dietary Guidelines for Americans and ChooseMyPlate.gov for recommended nutrition guidelines. Foods are usually the best source of vitamins because they have all the components necessary to be digested and used by the body. Some synthetic vitamin supplements can't be fully absorbed by the body, so you may not be getting as much of that vitamin as the capsule contains. Additionally, in the case of gummy vitamins, their focus on tasting good can detract from their actual nutritional value.

If you’re getting enough vitamins from food, taking a supplement may not help at all — or in some cases, it could even be toxic because taking more than the safe daily levels of vitamins can be harmful. Taking too much of a vitamin can have a number of side effects, such as nausea, heart rhythm problems, liver problems, birth defects, nerve damage, kidney stones, and more, depending which vitamin the person is over consuming. To know how much is too much, looking at the recommended dietary allowance of each vitamin can help give context to how much a person may need. Further, most vitamins indicate a daily value, which provide info on how much of that vitamin the supplement provides.

Although the general population may not experience much benefit from taking vitamin supplements, there are some groups who are advised to take specific supplements to improve their health. These groups include:

  • People over the age of 50: Individuals who are 50 or older are often advised to take extra vitamin B12 and vitamin D. These vitamins can be consumed through fortified foods or a supplement.
  • Pregnant people (and those who may become pregnant): Folic acid, considered a B vitamin, is essential for fetal development. Extra iron, which can be consumed through foods such as meat, spinach, and beans or through supplements, and vitamin C are also often recommended for pregnant women.
  • People with insufficient exposure to sunlight: People who don't spend very much time in the sun and people with darker skin are sometimes advised to increase their vitamin D intake — either through fortified foods or supplements.
  • People advised to take supplements by their health care provider: Certain illnesses or conditions may prompt a health care provider to prescribe vitamin supplements for their patients.

Regardless of the reason you might be considering vitamin supplements, doing research beforehand can help you avoid undesirable health outcomes. Because the Food and Drug Administration (FDA) doesn’t have jurisdiction over vitamin supplements in the same way that it does over prescription medication, the label may contain misleading information about the ingredients and effects of the supplements. Also, it may be risky to combine certain supplements with other supplements or medication, or to take supplements in place of prescription medication.

To see whether vitamins or dietary supplements may be safe and beneficial for you, you may consider talking to your health care provider or registered dietitian before taking any vitamin supplements, and when researching online, err towards non-commercial websites, such as the FDA or National Institutes of Health (NIH) for evidence-informed information. If the claims about a supplement seem too good to be true… it’s probably too good to be true.

To health!

Last updated Sep 06, 2019
Originally published Oct 01, 1994