{"url":"https://whatshealthyandwhy.com/multivitamins/should-you-take-a-multivitamin","path":"/multivitamins/should-you-take-a-multivitamin","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/multivitamins/should-you-take-a-multivitamin.json","markdown":"https://whatshealthyandwhy.com/multivitamins/should-you-take-a-multivitamin.md"},"topic":{"slug":"multivitamins","name":"Multivitamins","url":"https://whatshealthyandwhy.com/multivitamins"},"slug":"should-you-take-a-multivitamin","order":1,"title":"Should You Take a Multivitamin?","question":"Should you take a multivitamin?","answer":"Probably not if you eat well: large trials show little protection against heart disease, cancer or early death, though some groups clearly benefit.","description":"What the largest trials of a daily multivitamin found for heart disease, cancer, memory and lifespan, and who actually benefits from taking one.","confidence":4,"confidenceNote":"Two large, long randomized trials agree on heart disease and death; cancer and memory results differ, and both trials enrolled mostly well-nourished older US adults.","evidenceSummary":{"rctCount":4,"observationalCount":4,"metaAnalysisCount":2,"totalParticipants":"500,000+","replicated":true,"newestStudyYear":2024},"category":{"categoryTitle":"What's Good For You","categorySlug":"good-for-you","subcategoryName":"Supplements & Vitamins","subcategorySlug":"supplements","url":"https://whatshealthyandwhy.com/explore/good-for-you/supplements"},"actions":["Build your nutrition from food first: in a large US cohort, lower death rates tracked with nutrients eaten, not with supplements taken [1].","If planning pregnancy or able to become pregnant, take folic acid (400+ micrograms daily), alone or in a prenatal vitamin; it cut neural tube defects by about two thirds [2].","If you eat no animal foods, use a B12 supplement or B12-fortified foods, because deficiency was common in vegetarians of every age studied [3]."],"cautions":["Pregnant? Pick a prenatal formula and avoid products with over 10,000 IU a day of preformed vitamin A (retinol), linked to birth defects in a large cohort [4].","Skip add-on beta-carotene and vitamin E: the US Preventive Services Task Force advises against both for preventing heart disease or cancer [5].","If you take prescription medicines, ask a pharmacist to check any new multivitamin against them."],"simpleText":"For most healthy adults, a daily multivitamin does not clearly protect against heart disease, cancer or early death. Two large trials of more than 36,000 adults over 50 found no clear effect on heart attacks, strokes or lifespan [6][7], and the US Preventive Services Task Force calls the evidence insufficient [5]. It does help if you could become pregnant or eat no animal foods [2][3]. Older adults may gain a small memory boost, but results conflict [8][9].","mediumText":"How it works\n\nA multivitamin bundles many vitamins and minerals, each near the recommended daily amount. It is meant to fill gaps, not to act like a drug, so it works best where gaps are real.\n\nGaps are common. In a nationally representative US survey of 15,030 people, about 31% were at risk of at least one vitamin deficiency or anemia. Risk was 14% among users of full-spectrum multivitamins and 40% among non-users [10]. That comparison cannot prove cause, because people who take supplements differ in other ways.\n\nFood still does most of the work. In a cohort of 30,899 US adults, adequate intake of vitamin A, vitamin K, magnesium, zinc and copper went with lower death rates, but only when the nutrients came from food, not from pills [1].\n\nWho clearly benefits\n\n- Pregnancy or planning one. Folic acid, alone or inside a multivitamin, prevents neural tube defects (relative risk 0.31 across five trials), with similar results at 400 micrograms and above [2]. Choose a prenatal formula and avoid more than 10,000 IU of preformed vitamin A a day [4].\n- Diets with no animal foods. Researchers found B12 depletion or deficiency in vegetarians regardless of age or diet type [3]. See our vitamin B12 page.\n- Older adults may get a small memory benefit. Pooled data from three COSMOS substudies showed slightly better memory and overall thinking scores [8], though an earlier trial in male doctors found none [9].\n\nWhat to look for if you buy one\n\n- A plain once-daily formula near 100% of daily values. Avoid megadose products and extra beta-carotene or vitamin E [5].\n- A third-party testing seal. Our guide to telling if a supplement is pure explains what the seals mean.\n- Take it with a meal. Spacing rules for iron, calcium and thyroid medicine are in our supplement timing guide.","deepText":"The evidence in detail\n\nPhysicians' Health Study II\n\nThe longest trial of a multivitamin randomized 14,641 male US physicians aged 50 or older (mean age 64.3) to a daily multivitamin or placebo and followed them for a median of 11.2 years. Total cancer was modestly lower with the multivitamin: 17.0 versus 18.3 events per 1,000 person-years (hazard ratio 0.92, 95% CI 0.86 to 0.998). That barely cleared the threshold for statistical significance, and there was no effect on prostate cancer (HR 0.98) or colorectal cancer (HR 0.89, not significant) [11].\n\nIn the same men, a multivitamin did not change major cardiovascular events (HR 1.01, 95% CI 0.91 to 1.10), heart attack (HR 0.93), stroke (HR 1.06), cardiovascular death (HR 0.95) or total mortality (HR 0.94, 95% CI 0.88 to 1.02) [6]. A cognitive substudy of 5,947 men aged 65 or older, tested by telephone up to four times over 12 years, found no difference between groups (global score change -0.01 standard units, 95% CI -0.04 to 0.02). The authors noted that the doses may have been too low, or the men too well nourished, to benefit [9].\n\nCOSMOS\n\nCOSMOS randomized 21,442 US adults (12,666 women aged 65 or older and 8,776 men aged 60 or older) in a two-by-two design with cocoa extract. Over a median of 3.6 years, the multivitamin did not significantly change invasive cancer (HR 0.97, 95% CI 0.86 to 1.09), cardiovascular disease (HR 0.98, 0.86 to 1.12) or all-cause mortality (HR 0.93, 0.81 to 1.08). Lung cancer was lower (HR 0.62, 0.42 to 0.92), but that was one of several site-specific secondary outcomes and needs confirmation. No safety concerns emerged [7].\n\nMemory and thinking\n\nPooling three non-overlapping COSMOS cognitive substudies (573 + 2,158 + 2,472 participants), the multivitamin improved global cognition by 0.07 standard units (95% CI 0.03 to 0.11) and episodic memory by 0.06 (0.03 to 0.10), which the authors equated with about two years less cognitive aging. In the in-person clinic substudy alone, the global gain (0.06, 95% CI -0.003 to 0.13) was not significant, although memory was (0.12, 0.002 to 0.23) [8]. The effects are small, follow-up was two to three years, and the male-only PHS II trial found nothing [9]. This is a promising signal, not a reason by itself to start a multivitamin.\n\nObservational data\n\nLoftfield and colleagues pooled three US cohorts (390,124 adults, 164,762 deaths, up to 27 years of follow-up) and tried to account for healthy-user bias and for people starting vitamins when ill. Multivitamin use was not linked to lower mortality: HR 1.04 (1.02 to 1.07) in the first half of follow-up and 1.04 (0.99 to 1.08) in the second [12]. In NHANES data linked to deaths (30,899 adults, median 6.1 years), supplement use showed no mortality benefit, and calcium supplements of 1,000 mg a day or more went with higher cancer mortality (rate ratio 1.53, 95% CI 1.04 to 2.25) [1]. Both are observational and can be confounded.\n\nSpecific groups\n\nA Cochrane review of folic acid before and early in pregnancy pooled five trials in 7,391 women. Neural tube defects fell (relative risk 0.31, 95% CI 0.17 to 0.58; high-quality evidence) and so did recurrences (RR 0.34, 0.18 to 0.64), with no clear effect on other birth defects. Only one of the five trials had a low risk of bias [2]. A cohort of 22,748 pregnant women found that more than 10,000 IU a day of supplemental preformed vitamin A carried a prevalence ratio of 4.8 (95% CI 2.2 to 10.5) for defects arising from the cranial neural crest; the authors estimated that about 1 infant in 57 born to those users had a malformation attributable to the supplement [4]. A review of 18 studies found B12 depletion or deficiency in vegetarians of all ages, with rates from 11% to 90% among older vegetarians [3].\n\nWhere the evidence disagrees\n\nThe two large trials disagree on cancer (slightly lower in PHS II, no difference in COSMOS) and on thinking skills (nothing in PHS II, a small gain in COSMOS). Age, sex, length of follow-up and baseline nutrition differ between them, so neither is a clean test of the other [11][7]. The Task Force's 2022 review judged the evidence for multivitamins insufficient (an \"I statement\") and recommended against beta-carotene and vitamin E; it predates the pooled COSMOS cognition analysis [5][8]. The nutrient-gap data are the best argument for \"insurance\" use, but they are associations [10], and the large trials did not target people with documented deficiencies, so they say little about whether closing real gaps helps [6][7].\n\nBottom line (confidence 4 of 5). In well-nourished adults a multivitamin neither prevents heart disease or early death nor does much harm; cancer and memory findings are small and inconsistent. For pregnancy planning and for diets lacking B12 the case is strong. Food first, a plain formula second.","deepTruncated":false,"references":[{"id":"1","title":"Association Among Dietary Supplement Use, Nutrient Intake, and Mortality Among U.S. Adults: A Cohort Study","authors":"Chen F, Du M, Blumberg JB, et al.","year":2019,"journal":"Ann Intern Med","pmid":"30959527","url":"https://pubmed.ncbi.nlm.nih.gov/30959527/"},{"id":"2","title":"Effects and safety of periconceptional oral folate supplementation for preventing birth defects","authors":"De-Regil LM, Peña-Rosas JP, Fernández-Gaxiola AC, et al.","year":2015,"journal":"Cochrane Database Syst Rev","pmid":"26662928","url":"https://pubmed.ncbi.nlm.nih.gov/26662928/"},{"id":"3","title":"How prevalent is vitamin B(12) deficiency among vegetarians?","authors":"Pawlak R, Parrott SJ, Raj S, et al.","year":2013,"journal":"Nutr Rev","pmid":"23356638","url":"https://pubmed.ncbi.nlm.nih.gov/23356638/"},{"id":"4","title":"Teratogenicity of high vitamin A intake","authors":"Rothman KJ, Moore LL, Singer MR, et al.","year":1995,"journal":"N Engl J Med","pmid":"7477116","url":"https://pubmed.ncbi.nlm.nih.gov/7477116/"},{"id":"5","title":"Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement","authors":"Mangione CM, Barry MJ, Nicholson WK, et al. (US Preventive Services Task Force)","year":2022,"journal":"JAMA","pmid":"35727271","url":"https://pubmed.ncbi.nlm.nih.gov/35727271/"},{"id":"6","title":"Multivitamins in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial","authors":"Sesso HD, Christen WG, Bubes V, et al.","year":2012,"journal":"JAMA","pmid":"23117775","url":"https://pubmed.ncbi.nlm.nih.gov/23117775/"},{"id":"7","title":"Multivitamins in the prevention of cancer and cardiovascular disease: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial","authors":"Sesso HD, Rist PM, Aragaki AK, et al.","year":2022,"journal":"Am J Clin Nutr","pmid":"35294969","url":"https://pubmed.ncbi.nlm.nih.gov/35294969/"},{"id":"8","title":"Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS","authors":"Vyas CM, Manson JE, Sesso HD, et al.","year":2024,"journal":"Am J Clin Nutr","pmid":"38244989","url":"https://pubmed.ncbi.nlm.nih.gov/38244989/"},{"id":"9","title":"Long-term multivitamin supplementation and cognitive function in men: a randomized trial","authors":"Grodstein F, O'Brien J, Kang JH, et al.","year":2013,"journal":"Ann Intern Med","pmid":"24490265","url":"https://pubmed.ncbi.nlm.nih.gov/24490265/"},{"id":"10","title":"Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States","authors":"Bird JK, Murphy RA, Ciappio ED, et al.","year":2017,"journal":"Nutrients","pmid":"28672791","url":"https://pubmed.ncbi.nlm.nih.gov/28672791/"},{"id":"11","title":"Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trial","authors":"Gaziano JM, Sesso HD, Christen WG, et al.","year":2012,"journal":"JAMA","pmid":"23162860","url":"https://pubmed.ncbi.nlm.nih.gov/23162860/"},{"id":"12","title":"Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts","authors":"Loftfield E, O'Connell CP, Abnet CC, et al.","year":2024,"journal":"JAMA Netw Open","pmid":"38922615","url":"https://pubmed.ncbi.nlm.nih.gov/38922615/"}],"wordCount":1183,"source":{"path":"src/content/topics/multivitamins/should-you-take-a-multivitamin.md"},"citeAs":"“Should you take a multivitamin?.” What's Healthy and Why. https://whatshealthyandwhy.com/multivitamins/should-you-take-a-multivitamin","notice":"General information backed by peer-reviewed research, not medical advice."}