Why do doctors not recommend multivitamins? The truth about supplements

October 9, 2025 •

3 min read

According to a 2024 JAMA study, there is little health rationale for the widespread use of multivitamin supplements among healthy people. So, why do doctors not recommend multivitamins for everyone, and what does the science say about their effectiveness and safety?

Quick Summary

Most physicians do not recommend routine multivitamins for healthy individuals, prioritizing a balanced diet instead. Research shows limited evidence for preventing chronic disease and highlights potential risks from excessive intake or drug interactions. Supplements should be used to address specific, diagnosed deficiencies, not as a blanket insurance policy.

Key Points

Food First, Always: A varied diet provides a complex, synergistic mix of nutrients, fiber, and phytochemicals that supplements cannot replicate.
Limited Efficacy for Healthy People: Large-scale studies show little evidence that multivitamins prevent chronic diseases like cancer, heart disease, or cognitive decline in healthy individuals.
Potential Risks of Overdose: Excessive intake, particularly of fat-soluble vitamins (A, D, E, K), can lead to toxicity, and mineral imbalances are a risk.
The Placebo Effect: Some perceived benefits from multivitamins may be due to the placebo effect or healthier lifestyle habits of those who take them.
Targeted Use for Specific Needs: Doctors recommend supplementation primarily for specific populations with diagnosed deficiencies or special needs, such as pregnant women, older adults, or those with malabsorption issues.

A balanced diet versus the pill

The fundamental reason most doctors prefer a food-first approach is simple: a balanced diet provides a synergistic array of nutrients that a pill cannot replicate. Whole foods contain a complex mix of vitamins, minerals, fiber, and phytochemicals that work together in ways that are not fully understood. Isolating these components into a supplement often removes them from this powerful biological context.

Inconsistent and limited evidence for benefits

For most healthy individuals, the potential benefits of routine multivitamin supplementation have not been convincingly demonstrated by robust scientific studies. A review found insufficient evidence to recommend for or against multivitamins to prevent cardiovascular disease or cancer. Research has shown mixed or neutral results for most outcomes. Some studies suggest benefits for specific subgroups, but others link high doses to increased risks in certain populations. Research on cognitive effects has shown limited benefits, particularly in the general population. A significant portion of multivitamin users may be benefiting from a placebo effect. Studies have also shown that people who regularly take multivitamins tend to have healthier lifestyles already. This can create a misleading impression that the supplements are responsible for their good health, a phenomenon known as the 'worried well' effect. Relying on a pill can create a false sense of security, potentially causing people to neglect their diet and lifestyle.

Potential risks of multivitamin use

Multivitamins carry several potential risks, especially when taken without medical supervision or in excessive amounts.

Toxicity from excessive intake

Taking megadoses of certain vitamins can be harmful. Fat-soluble vitamins (A, D, E, K) can accumulate in the body and become toxic, which is a concern with unregulated supplements.

Mineral imbalances and interactions

Multivitamin formulations can cause imbalances or interfere with the absorption of other nutrients. For example, excessive zinc can hinder copper absorption, and high iron levels can be toxic, particularly for adult men and postmenopausal women.

Negative drug interactions

Some vitamins can interact dangerously with prescription medications. Vitamin K, for instance, can interfere with blood thinners like warfarin. Healthcare providers need to be aware of any supplements a patient is taking.

Contamination and lack of regulation

The supplement industry is not regulated as strictly as the pharmaceutical industry. Products may not contain the ingredients or dosages listed and could be contaminated. Consumers can look for third-party testing seals (e.g., USP or NSF) for quality assurance.

Food vs. multivitamin: A comparison


Feature	Balanced Diet (Whole Foods)	Multivitamin Supplement
Nutrient Complexity	Provides a broad and complex spectrum of interacting nutrients, fiber, and antioxidants.	Contains isolated and standardized doses of specific vitamins and minerals.
Bioavailability	Nutrients are often more bioavailable and easily absorbed in their natural food matrix.	Absorption can be less efficient due to isolation and potential nutrient-nutrient interactions within the pill.
Added Benefits	Offers fiber, beneficial phytochemicals, and promotes healthier eating habits.	Lacks fiber and other complex bioactive compounds found in food.
Risk of Toxicity	Extremely low risk of overdose when consuming a varied diet.	Higher risk of consuming toxic amounts of fat-soluble vitamins or minerals if combined with fortified foods or other supplements.
Primary Purpose	Long-term, holistic health and chronic disease prevention for the general population.	Bridging specific, diagnosed nutritional gaps under medical supervision.

When are multivitamins recommended?

While not for everyone, multivitamins are appropriate for specific populations with a higher risk of nutritional deficiencies. These include:

Pregnant or breastfeeding women: Often advised to take prenatal supplements for fetal development and to prevent anemia.
Older adults: Individuals over 50 may have difficulty absorbing certain nutrients like vitamin B12.
Individuals with dietary restrictions: Vegans or vegetarians may need supplementation for nutrients like vitamin B12, iron, and calcium.
Those with medical conditions: People with digestive disorders or chronic illnesses that impair nutrient absorption may require specific supplements prescribed by a doctor.

Conclusion

For the average, healthy person with a reasonably balanced diet, the medical consensus is that routine multivitamin use offers little to no proven benefit and carries some risks. A diverse diet rich in whole foods is the superior source of nutrients for long-term wellness. Multivitamins are not a substitute for healthy eating. For individuals with specific, diagnosed deficiencies or heightened needs, targeted supplementation, as advised by a healthcare professional, is the most responsible and effective approach. It is always best to consult with a doctor or dietitian before starting any supplement regimen. You can learn more about healthy eating guidelines from the {Link: World Health Organization https://www.who.int/health-topics/healthy-diet}.

Frequently Asked Questions

For most healthy people with a balanced diet, the evidence suggests that routine multivitamins are largely unnecessary and may not offer significant health benefits, meaning they could be a waste of money.

Yes, multivitamins can be harmful, particularly when taken in excessive doses. High levels of fat-soluble vitamins can become toxic, and some minerals can cause imbalances or negative interactions with medications.

A major issue with multivitamins is that they are not a substitute for a healthy diet. They lack the complex mix of fiber, nutrients, and other beneficial compounds found in whole foods, which often work together for better absorption and health outcomes.

In many countries, including the U.S., the supplement industry is less strictly regulated than the food or pharmaceutical industries. This can lead to variations in product quality, dosage accuracy, and a higher risk of contamination.

It is appropriate to take a multivitamin only when a specific nutritional deficiency is identified, or in certain life stages like pregnancy, when advised by a healthcare provider. Targeted supplements for specific nutrients are often more effective than generic multivitamins.

Dietary nutrients from whole foods are often more bioavailable and come with co-factors that aid absorption. Supplements provide isolated nutrients, which may not be absorbed as efficiently and can lead to imbalances if not managed carefully.

Yes, some multivitamins can interact with medications. For example, Vitamin K can interfere with blood thinners like warfarin, and certain minerals can affect the absorption of antibiotics.