Vitamins were first recognized as essential in the late 19th century (scurvy and citrus). While a varied diet should supply most nutrients, particular groups - pregnant people, older adults, strict vegans, and those with malabsorption - may need supplements. Evidence does not support routine multivitamin use for preventing chronic diseases in well-nourished adults. Use supplements to treat diagnosed deficiencies or as clinically recommended, and consult a healthcare professional before starting them.

Why vitamins matter

Scientists only recognized the role of vitamins in the late 19th and early 20th centuries. Classic examples such as scurvy - prevented by citrus fruit - show how a single nutrient deficiency can cause serious disease. Today most people get many necessary nutrients from food, but some dietary patterns and life stages can leave gaps.

Food first, supplements second

A balanced diet remains the best way to meet vitamin needs. Vegetables, fruit, whole grains, lean proteins, dairy or fortified alternatives provide most vitamins and minerals. That said, many adults do not meet recommended intakes for certain foods, and supplements can help bridge shortfalls.

Who may benefit from a multivitamin or specific supplements

  • Pregnant people or those planning pregnancy: folic acid (folate) before and during early pregnancy reduces the risk of neural tube defects. A prenatal multivitamin is commonly recommended.
  • Older adults: age-related changes in stomach acid and digestion can lower absorption of vitamin B12. Vitamin D deficiency is also more common as people age or have limited sun exposure.
  • People on restrictive diets: strict vegans often need reliable vitamin B12 sources because it is scarce in plant foods. Others on calorie-restricted or therapeutic diets may miss nutrients and benefit from targeted supplementation.
  • People with malabsorption, chronic medical conditions, or certain medications: these conditions can impair nutrient absorption and increase needs.
For these groups, clinicians often recommend specific nutrients (for example, folate, vitamin B12, or vitamin D) rather than a general high-dose multivitamin. The right choice depends on diet, medical history, lab tests, and medications.

What the evidence says about routine multivitamin use

Large trials and reviews show mixed results for multivitamins in preventing chronic diseases in the general population. Multivitamins can help correct deficiencies but have not consistently been shown to prevent heart disease or most cancers in well-nourished adults. Vitamin-specific risks exist: for example, excess preformed vitamin A can be harmful in pregnancy, and iron-containing supplements can cause side effects if taken unnecessarily.

Practical guidance

  • Aim to meet most nutrient needs through a varied diet.
  • Use supplements to address clear gaps or medically diagnosed deficiencies, or when recommended by a clinician (for example, prenatal folic acid, infant vitamin D, or B12 for certain adults).
  • Avoid high-dose single vitamins without medical advice.
  • Talk to your doctor or a registered dietitian before starting supplements, especially if you take medications, are pregnant, or have chronic health conditions.
This approach keeps the original idea - that diet is central - while reflecting current understanding: supplements can be useful for specific needs but are not a universal substitute for healthy eating.

FAQs about Multiple Vitamins

Do multivitamins prevent colds or chronic disease?
Evidence does not support routine multivitamin use to prevent most chronic diseases in well-nourished adults. Some vitamins (like vitamin C) may slightly shorten cold duration when taken regularly, but they are not a cure.
Who should take a multivitamin?
People with diagnosed nutrient gaps, such as pregnant people (folic acid), older adults (B12, vitamin D), strict vegans (B12), and those with malabsorption or restrictive diets may benefit from targeted supplements.
Can supplements replace a healthy diet?
No. Whole foods provide fiber, phytonutrients, and a balance of nutrients that supplements cannot fully replicate. Supplements should fill gaps, not replace varied eating.
Are there risks to taking vitamins?
Yes. High doses of some vitamins (for example, preformed vitamin A) can be harmful. Iron supplements can cause side effects if not needed. Consult a clinician before taking high-dose or multiple supplements.