You have seen the headline. Vitamins are a waste of money. It usually traces back to a real federal document, and the document says something much narrower than the headline does.
In June 2022 the U.S. Preventive Services Task Force, the volunteer panel of clinicians and researchers that grades preventive care for American medicine, published its conclusions on vitamin, mineral and multivitamin supplements taken to prevent cardiovascular disease and cancer. It recommended against beta carotene and vitamin E for that purpose, its grade D. For multivitamins, and separately for other single or paired nutrients, it concluded that the evidence was insufficient to weigh benefits against harms, which the panel labels an I statement.
Then the statement prints a line that is almost always left behind when the finding gets repeated. “This recommendation applies to community-dwelling, nonpregnant adults.” Alongside it sits the list of people the recommendation does not apply to: children, people who are pregnant or may become pregnant, and people who are chronically ill, hospitalized, or have a known nutritional deficiency.
Read that exclusion list twice. The panel removed from its own scope very nearly every group in which nutrient supplementation has clear evidence behind it. So the finding is not that supplements do nothing. The finding is that among healthy adults living in the community, who are not pregnant and not known to be deficient, taking these products to prevent heart disease or cancer has not been shown to work. Those are different claims, and the difference is the whole subject.
The sentence that decides who a finding covers
Grades from the task force are not opinions about a product. They are verdicts about a specific intervention, for a specific outcome, in a specific population, and all three parts travel together.
A grade D means the panel found at least moderate certainty that the harms equal or exceed the benefits. In the 2022 statement, beta carotene earned that grade partly because two trials in people who smoked or had been exposed to asbestos found a significantly increased risk of lung cancer among those assigned beta carotene. That is an outcome measured in people and reported by a federal panel, not a theoretical harm.
Vitamin E’s share of that same grade has a similar history. A trial reported in JAMA in 2011 randomized 35,533 men at 427 sites across the United States, Canada and Puerto Rico, assigning some of them 400 international units of vitamin E a day. It was designed to look for protection against prostate cancer. It found 620 cases in the vitamin E group against 529 on placebo, and concluded that supplementation significantly increased the risk. Article 326 covers what the big prevention trials taught the field about evidence.
An I statement is a different animal and it is routinely misread. It does not mean the intervention failed. It means the panel could not determine the balance of benefits and harms from the evidence available. Multivitamins sit there. So does almost every other single nutrient studied for these two outcomes. Insufficient evidence is a statement about the research record, not a verdict on the pill.
The population clause does the heaviest lifting. Community-dwelling means people living in the community rather than in a hospital or a nursing facility. Nonpregnant removes pregnancy from scope. And the exclusion of people with a known nutritional deficiency removes, by definition, anyone whose clinician has already found a nutrient problem and is treating it.
Picture two people reading the same news story about that statement. One is 42, eats a varied diet, has no diagnosis and takes a multivitamin because it seems sensible. The statement was written about her. The other is 71, had most of his stomach removed for cancer a decade ago and takes B12 because his hematologist prescribed it. The statement was written to exclude him. Same headline, same product category, opposite relevance. Article 321 covers how deficiency is measured and how common it is. The point here is only that the task force drew its boundary deliberately and put the boundary in writing.
One nutrient, two opposite grades
The cleanest proof that evidence attaches to populations rather than to molecules comes from the same panel, in the same decade, about folic acid.
The 2022 statement excludes people who are pregnant or may become pregnant. The task force addresses that group in a separate recommendation, finalized on August 1, 2023, and it is a grade A, the panel’s strongest. The published recommendation is that all persons planning to or who could become pregnant take a daily supplement containing 0.4 to 0.8 mg, which is 400 to 800 micrograms, of folic acid. The outcome in question is prevention of neural tube defects in a developing fetus.
So one federal panel says the evidence is insufficient for multivitamins in healthy adults and strongest-grade positive for folic acid in people who could become pregnant. Both statements are current. Neither contradicts the other, because they are answers to different questions.
That is the structure to carry into any supplement claim you encounter. Which nutrient, in which people, for which outcome, measured over what period. Drop any one of the four and the sentence stops meaning anything. Article 356 covers pregnancy and breastfeeding in detail, including where the professional bodies disagree.
Where the evidence does point at a group
Vitamin B12 is the clearest worked example of why some populations sit outside the healthy-adult finding, because the reason is mechanical and easy to see.
B12 absorption depends on intrinsic factor, a protein made by cells in the stomach lining, and on stomach acid to free the vitamin from food protein. Break either step and intake stops predicting status. According to the NIH Office of Dietary Supplements health professional fact sheet, updated July 2, 2025, pernicious anemia is an autoimmune disease that damages the stomach lining and shuts down intrinsic factor production, so deficiency develops even when dietary intake is perfectly adequate. The fact sheet reports it is present in about 15 to 25 percent of older adults who have B12 deficiency.
Atrophic gastritis works the same way by a slower route, reducing both acid and intrinsic factor. The same fact sheet puts it at about 2 percent of the general population and 8 to 9 percent of adults aged 65 and older. It also reports that, depending on which laboratory definition is used, somewhere between 3 and 43 percent of community-dwelling older adults show B12 deficiency on serum testing. That range is enormous, and the honest reading is that the measurement question is unsettled rather than that the true figure sits in the middle.
Three other routes to the same place appear on that sheet. Surgery that removes the acid-secreting and intrinsic-factor-secreting parts of the stomach reduces how much B12, particularly B12 bound to food, the body takes up. Vegans and vegetarians carry higher risk because natural food sources of B12 are limited to animal foods. And two very common drug classes interfere: metformin might reduce B12 absorption and significantly lower serum concentrations, and proton pump inhibitors and H2 blockers can interfere with absorption from food by slowing the release of gastric acid.
The adult Recommended Dietary Allowance for B12 is 2.4 micrograms a day, set by the Food and Nutrition Board; article 322 explains what a Recommended Dietary Allowance is and is not. None of this tells any particular reader anything about their own status. It explains why a clinician treats a vegan on long-term metformin as a different problem from a 30-year-old omnivore who read a headline.
Bariatric surgery is the other population where a professional body has written the question down. The American Society for Metabolic and Bariatric Surgery published a micronutrient guideline update in 2016, printed in Surgery for Obesity and Related Diseases in 2017, covering vitamins B1 and B12, folate, iron, vitamins A, E and K, calcium, vitamin D, copper and zinc across five procedures. It carries 92 recommendations, 79 of them new, each with a graded level of evidence from A through D. Two sentences in it are worth more than the count. The guideline states that it is common for patients arriving for weight loss surgery to have at least one vitamin or mineral deficiency before any operation. And it reports that the prevalence of micronutrient deficiencies appears to be rising while monitoring of patients at follow-up is falling.
A professional body that published something close to a decision tree
The closest thing in this subject to a published decision framework arrived in 2024, and it came from endocrinologists rather than from a prevention panel.
The Endocrine Society’s clinical practice guideline on vitamin D for disease prevention, published in The Journal of Clinical Endocrinology and Metabolism in 2024, was built by a multidisciplinary panel using GRADE, a formal system for rating how much confidence a body of evidence deserves. The panel prioritized 14 clinical questions and restricted itself to people without an established reason for vitamin D treatment or testing.
Its most useful move was defining its terms. The panel defined empiric supplementation as vitamin D intake that both exceeds the Dietary Reference Intakes and is implemented without testing blood levels first. That definition is what makes the rest of the guideline readable, because it separates supplementing in response to a test result from supplementing on the basis of who someone is.
The panel then suggested empiric vitamin D for four named groups, each with a stated reason. Children and adolescents aged 1 to 18, to prevent nutritional rickets and for its potential to lower the risk of respiratory tract infections. People aged 75 and older, for its potential to lower mortality. People who are pregnant, for its potential to reduce preeclampsia, intrauterine mortality, preterm birth, small-for-gestational-age birth and neonatal mortality. And people with high-risk prediabetes, for its potential to slow progression to diabetes.
Just as important is what the panel suggested against: empiric vitamin D above the current Dietary Reference Intakes to lower disease risk in healthy adults younger than 75. For nonpregnant people older than 50 who do have an indication, the panel suggested daily dosing rather than intermittent high doses.
The guideline is unusually candid about its own limits. The panel wrote that optimal doses for empiric supplementation remain unclear for the populations it considered, because trial doses varied widely and many trial participants were allowed to keep taking their own vitamin D products. It also states plainly that these recommendations are not meant to replace the Dietary Reference Intakes and do not apply to people who already have an established indication for treatment or testing.
Four groups with reasons, one group with a reason not to, and an admission that the dose is unknown. That is what an honest decision framework looks like, and it is narrower than most readers expect.
The testing question, and why it is not an argument against testing
Here is where the subject gets genuinely uncomfortable, and the discomfort is worth sitting with rather than smoothing over.
The 2024 endocrine panel suggested against routine 25-hydroxyvitamin D testing in every population it considered, including the four groups it suggested supplementing. Its reason was an absence. The trials that would have settled the question do not exist, for the general population or for the subgroups the panel looked at separately, among them people with obesity and people with dark skin. Supplement some groups, test almost nobody. Those sit oddly together until you notice that both follow from the same gap: nobody has established what level a test result should be compared against.
The U.S. Preventive Services Task Force reached a similar place three years earlier by a different road. Its April 13, 2021 statement on screening for vitamin D deficiency in adults without signs or symptoms is a grade I, which the panel defines as a balance of benefits and harms that cannot be determined. The reasoning the panel gave is the part worth remembering: there is no single level of vitamin D that counts as too low for everyone. Task force members described the research sequence that would be needed, which is to establish what level is too low before anyone can study whether screening for it improves outcomes such as falls, cancer or heart problems.
None of this is an argument against getting a blood test. It is a statement about testing people who have no symptoms and no clinical reason, which is a different act from testing someone whose clinician has a question. The 2021 statement explicitly does not apply to people who already have conditions requiring vitamin D treatment. Article 321 covers what these markers measure and what they do not.
Food first, in an agency’s own words
The federal position on where nutrients should come from is short enough to quote in full. Among the key dietary principles in the Dietary Guidelines for Americans 2020-2025, published jointly by the U.S. Department of Agriculture and the Department of Health and Human Services, is this: “Meet nutritional needs primarily from foods and beverages.”
That page does not mention supplements at all, which is itself informative. The Office of Dietary Supplements is more direct in its consumer fact sheet, which says supplements cannot take the place of the variety of foods that matter to a healthy eating pattern, and that these products are not medicines and are not intended to treat, diagnose, mitigate, prevent or cure disease.
Food-first is not a moral position. It is a practical one. Nutrients in food arrive with fiber, with other nutrients that affect their absorption, and in amounts that are hard to overshoot. Article 323 covers tolerable upper intake levels and why the ceiling matters more for isolated nutrients than for meals.
Most American supplement use is not in any of these groups
Now the arithmetic that the industry’s own market size makes awkward.
National Center for Health Statistics figures, published as Data Brief No. 399 in February 2021 and drawn from the 2017 to 2018 survey rounds, put use within the previous month at 57.6 percent of American adults from age 20 up. Women ran ahead of men, 63.8 percent against 50.8 percent, and the figure peaked at 80.2 percent among women past 60.
Set those two facts side by side. More than half of American adults take something. The most-used categories are precisely the ones the task force graded as insufficient evidence or recommended against for preventing heart disease and cancer in healthy community-dwelling adults. The groups with documented benefit, people with diagnosed deficiency, malabsorption, post-surgical anatomy, restrictive diets, pregnancy, early childhood and advanced age, do not add up to anything near 57.6 percent of adults.
That last sentence is an inference, and it deserves to be labeled as one. No federal agency publishes a statement saying most American supplement use falls outside a documented-benefit population. The conclusion is built by putting the prevalence survey next to the task force’s population exclusions next to the Endocrine Society’s suggestion against empiric dosing in healthy adults under 75. The components are each well sourced. The sum is reasoning, not a citation, and anyone repeating it should say so.
The question worth taking to an appointment
The useful move is not deciding whether supplements work. It is working out which of the four variables in your situation is known, and that is a clinical question with a clinical answer.
A short list of things worth asking a clinician or pharmacist, built from the structure above rather than from any product label:
- Which specific outcome is this product supposed to change, and in which population was that outcome measured?
- Is there a reason to think I am in a group where intake does not predict status, because of absorption, surgery, diet pattern or a medication I take?
- If a blood test is being proposed, what will a result change, and what level is it being compared against?
- If something is already being taken, what would tell us it is doing anything, and when would we check?
- Which of this belongs in my chart, so the next clinician sees it?
Article 779 covers how to have that conversation. Article 359 covers the record you bring to it.
One thing deserves saying plainly before you go. Supplements being unproven for preventing disease in healthy adults does not make them inert. Federal surveillance has repeatedly documented real harm from these products, and article 355 covers what excessive doses do. Unproven benefit and documented harm can both be true at once, and in this subject they usually are.
Get professional help rather than a search engine if you notice the kinds of signs the Office of Dietary Supplements lists under B12 deficiency: numbness and tingling in the hands and feet, fatigue, palpitations, pale skin, an inflamed tongue, unexplained weight loss. The same fact sheet makes one point that matters more than the list itself. Neurological symptoms can appear without anemia, which means a normal blood count does not close the question.
Those signs are also the ones most easily explained by something other than a nutrient, which is precisely why they belong in front of somebody who can examine you rather than in a shopping cart.
Sources
- U.S. Preventive Services Task Force. “Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: Preventive Medication (final recommendation, June 21, 2022; population and exclusion language under Patient Population Under Consideration).” uspreventiveservicestaskforce.org
- U.S. Preventive Services Task Force. “Folic Acid Supplementation to Prevent Neural Tube Defects: Preventive Medication (Grade A, final recommendation August 1, 2023).” uspreventiveservicestaskforce.org
- U.S. Preventive Services Task Force. “Final Recommendation Bulletin: Screening for Vitamin D Deficiency in Adults (Grade I, April 13, 2021).” uspreventiveservicestaskforce.org
- Centers for Disease Control and Prevention, National Center for Health Statistics. “Mishra S, Stierman B, Gahche JJ, Potischman N. Dietary Supplement Use Among Adults: United States, 2017-2018. NCHS Data Brief No. 399, February 2021.” cdc.gov
- National Institutes of Health, Office of Dietary Supplements. “Vitamin B12: Fact Sheet for Health Professionals (updated July 2, 2025).” ods.od.nih.gov
- National Institutes of Health, Office of Dietary Supplements. “Dietary Supplements: What You Need to Know (updated January 4, 2023).” ods.od.nih.gov
- U.S. Department of Agriculture and U.S. Department of Health and Human Services. “Top 10 Things You Need to Know About the Dietary Guidelines for Americans, 2020-2025.”
- The Journal of Clinical Endocrinology and Metabolism (verified via PubMed). “Demay MB, Pittas AG, Bikle DD, et al. "Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline." J Clin Endocrinol Metab, 2024;109(8):1907-1947. PubMed. DOI: 10.1210/clinem/dgae290.” doi.org
- Surgery for Obesity and Related Diseases (verified via PubMed). “Parrott J, Frank L, Rabena R, Craggs-Dino L, Isom KA, Greiman L. "American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients." Surg Obes Relat Dis, 2017;13(5):727-741. PubMed. DOI: 10.1016/j.soard.2016.12.018.” doi.org
- JAMA (verified via PubMed). “Klein EA, Thompson IM, Tangen CM, et al. "Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT)." JAMA, 2011;306(14):1549-1556. PubMed. DOI: 10.1001/jama.2011.1437.” doi.org