Walk into any health store and the shelves go up to the ceiling. Vitamins, minerals and herbs, each one promising more energy, better immunity or a longer life. It's an old question whether these are really necessary or just expensive placebos.
The honest answer is a bit worse than that. A few of them have been tested on tens of thousands of people, at great expense, by researchers who fully expected them to work. And in two of the biggest, the people taking the pills did worse than the people on a dummy pill. A placebo would have been a bargain.
So before you decide what you need, it's worth knowing how that happened.
The promise
In 1981 a group of eminent researchers, Richard Peto and Richard Doll among them, published a paper with a question for a title: could dietary beta-carotene materially reduce human cancer rates? People with more of it in their diet had less cancer. It's the orange pigment in carrots, it was cheap and it looked harmless. The authors were careful. They said that if it was truly protective, controlled trials could test it.
So the trials were run, and they were enormous.
The trials
In Finland, 29,133 male smokers aged 50 to 69 were assigned to beta-carotene, vitamin E, both or a dummy pill, then followed for five to eight years. The expectation was fewer lung cancers. Among the men taking beta-carotene, there were 18% more. The vitamin E made no difference to lung cancer at all.
Two years later came the American trial. 18,314 smokers, former smokers and asbestos workers took beta-carotene with vitamin A or a dummy pill. Lung cancer was up 28%. Deaths from lung cancer were up 46%, and deaths from any cause were up 17%. It was stopped 21 months early on the strength of those findings.
Keep in mind what was in that pill. It was a vitamin, from a respectable manufacturer, taken in good faith by people trying to protect themselves.
In 2022 the US Preventive Services Task Force gave its verdict. It recommends against beta-carotene or vitamin E for preventing heart disease or cancer, and says the evidence isn't good enough to judge multivitamins or most other single supplements.
The men and women in those trials were followed for years afterwards, and there's some comfort in it. In Finland, 18 years of follow-up among 25,563 men found no significant effects once the pills had stopped. In the American trial the risks stayed somewhat above normal for a while, at 1.12 for lung cancer, and fell back faster for heart deaths. So the damage seems to fade when you stop, and that's a good reason to stop.
Why it fooled everyone
The first clue had come from comparing people. The ones with more beta-carotene in their diets had less cancer. But people who eat more of anything tend to differ in a hundred other ways, and a comparison like that can't untangle them. Only a trial can, by handing out the pill at random.
There's a second problem. A compound in a food isn't the same thing as that compound in a capsule, taken alone, at a level no meal would deliver. Why beta-carotene did this to smokers still isn't fully settled. What matters is that it took a trial on people to find out.
It wasn't a one-off
Why Your Fruits and Vegetables Deliver Less Than You Think has the pooled antioxidant tests: 68 of them, 232,606 people and no fewer deaths. Why Your Mineral Supplements Keep Canceling Each Other Out has the selenium that made aggressive prostate cancer more likely in men who already had plenty, and the vitamin E that did the same. The Quiet Signals of Mineral Deficiency has the calcium tablets and the heart attacks, and the 390,124 healthy adults whose daily multivitamin didn't help them live any longer.
The B vitamins may belong on the list too. In a study of 77,118 people, men who'd taken high levels of B6 or B12 from individual supplements for years had nearly double the risk of lung cancer, and the risk was higher still in those who smoked. There was no such link in women. That's a comparison of people, the kind of evidence that started the beta-carotene story, so it isn't proof. But you'd want a good reason to take those amounts.
Even the two most popular pills of the moment have had their fair test. 25,871 people took vitamin D, omega-3s or a dummy pill for a median of 5.3 years. Neither supplement lowered cancer or major heart events: 793 cancers against 824 with vitamin D, and 386 heart events against 419 with omega-3s, neither of them a significant difference. Filling a real shortage is one thing. Taking a pill to prevent disease in someone who isn't short is another, and that's what those trials tested.
B6 has a harm of its own. The NHS says too much of it can cost you the feeling in your arms and legs. It usually improves when you stop, but in a few cases, especially after large amounts for more than a few months, it can be permanent. It turns up in plenty of energy and stress products, so check each label and add them up.
And vitamin C, the most innocent bottle of the lot? Among 23,355 Swedish men followed for about 11 years, those taking vitamin C supplements had about twice the risk of kidney stones, while multivitamins showed no such link. Your kidneys were not consulted. That's a comparison again, in men only, and the authors want it repeated.
What's in the bottle
All of that is what can go wrong when the label is accurate. From 2007 to 2016, the FDA named 776 supplements with hidden drugs in them, from 146 companies. Nearly half of those were sold for sexual enhancement, and 47% of those contained sildenafil, the drug in Viagra. So some of them did work, which should have been the first clue. Most of the rest were for weight loss, where 84.9% contained sibutramine, a drug taken off most markets in 2010 over heart concerns, or muscle building, where 89.1% contained steroids or something like them.
Five Herbs That Support Liver Function — and the Specific Mechanisms Behind Each One has the other end of it: of 839 liver injury cases in one US network, 130 came from herbs and supplements, with the share climbing from 7% to 20%. Why Most Stress Supplements Fail (And the 9 Worth a Look) has why no regulator checks these products before sale in the US, and what the words on the label do and don't mean.
The pill that makes you careless
There's one more cost, and chemistry isn't part of it. In two experiments, people were given a placebo. Those told it was a dietary supplement then wanted to exercise less, preferred a buffet to an organic meal, and walked less than those told it was a placebo. Believing you've taken your vitamins seems to license the rest of the day.
How pills got here
The word is barely a century old. In 1912 the biochemist Casimir Funk coined "vitamine", from "vital amine", for the substances in food whose absence caused diseases such as beriberi. The early work was about shortage. Chickens fed polished rice fell ill, and unpolished rice prevented it.
Those were real victories, and they left a lasting idea behind: if a little of something cures a disease of lack, then more of it must make a healthy person healthier. That's the jump that has never been shown, and those trials show what it can cost. The Finnish results came out in April 1994. Later that same year, the US Congress passed the law that exempted supplements from most FDA drug rules. Catherine Price's tells the longer story of how vitamins got their reputation.
When a pill earns its place
This isn't an argument against every bottle.
Before and in early pregnancy. Folic acid is the great success story. In a trial across seven countries, among women who'd already had an affected pregnancy, it cut neural tube defects by 72%. This one isn't only for women at high risk. The NHS says to take a folic acid supplement for the first 12 weeks of pregnancy, and to start before you conceive, ideally three months before, if you're planning one.
If you don't eat animals. B12 is the obvious one, and it isn't the only one. Why Eating Well Isn't Enough Anymore, linked below, has the 689 Oxford men, and the long list of what plant eaters lack.
In a northern winter. Your skin can't make vitamin D from weak sun, and few foods carry much of it.
If you eat no seafood. Iodine is the one to watch, and good unrefined salt won't cover it.
If a test says so. Nutrient Deficiencies: Who's at Risk and Which Test to Get, linked below, has which symptoms and groups are worth testing. A real shortfall is worth treating, and a guess isn't.
Food first
The old advice is right in spirit, because no pill makes up for a poor diet. Its usual examples are oranges and whole grains, though, and they're not where the concentrated nutrition is. Liver carries ready-made vitamin A, folate and B12. Fatty fish carry the long omega-3s and some vitamin D, and are the cheapest way in. Red meat carries iron and zinc in forms you absorb well, and eggs cover a good deal of what's left.
Eat the whole animal, with Fergus Henderson's if you want ideas, and you need very little from a bottle, and the gaps are short and specific: sun in winter, and seafood or something else for iodine. Why Eating Well Isn't Enough Anymore has the longer version.
Liver is the one to respect, as it's so rich in vitamin A that a small portion is plenty. Five Herbs That Support Liver Function has the explorers who fell ill on polar bear liver in 1597, though beef liver is far milder. Vitamin A and iron are also the two supplements where more is plainly not better, so don't take either without a reason.
What to do, in order
Find out what you're actually short of. Test first, before iron or anything else in a high amount.
Empty the shelf of anything you can't justify. Ask of each bottle what it's for, and what you'd notice without it. Your wallet will notice first.
Stay away from the worst categories. Sexual enhancement, weight loss and muscle building are where the hidden drugs turn up.
If you smoke or used to, avoid beta-carotene. Check your multivitamin for it as well.
Tell whoever prescribes your medicines. Supplements can clash with them, and Why Most Stress Supplements Fail has St John's wort as the best-known offender.
Build the plate first. Meat, fish, eggs and some liver, and then see what's left to fill.
Those researchers in 1981 asked a sensible question and then did the right thing, which was to test it. Do the same with your own shelf. Pick up one bottle tonight and ask what it's for. If you can't answer, you've found your first one to stop.
Wondering what you're actually short of? Nutrient Deficiencies: Who's at Risk and Which Test to Get — who is genuinely at risk, which test to ask for, and what to ignore.
Want to see what the plate can do by itself? Why Eating Well Isn't Enough Anymore — why plant eaters run short, and why eating the whole animal leaves so little to fill.
Know someone whose breakfast comes with a dozen pills? Send them this, and ask what each one is for.
Disclaimer: This article is general information. For advice about your own health, talk to a qualified health professional, especially before stopping anything you've been told to take.
Affiliate Disclosure: This article contains affiliate links. As an Amazon Associate, All For Life earns from qualifying purchases, at no extra cost to you. We only link to products we would recommend without the commission.
Sources
Peto R, Doll R, Buckley JD, Sporn MB (1981). Can dietary beta-carotene materially reduce human cancer rates? Nature 290(5803):201–208. doi.org/10.1038/290201a0
Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (1994). The Effect of Vitamin E and Beta Carotene on the Incidence of Lung Cancer and Other Cancers in Male Smokers. New England Journal of Medicine 330(15):1029–1035. doi.org/10.1056/NEJM199404143301501
Omenn GS, Goodman GE, Thornquist MD, et al. (1996). Effects of a Combination of Beta Carotene and Vitamin A on Lung Cancer and Cardiovascular Disease. New England Journal of Medicine 334(18):1150–1155. doi.org/10.1056/NEJM199605023341802
US Preventive Services Task Force (2022). Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer. JAMA 327(23):2326–2333. doi.org/10.1001/jama.2022.8970
Virtamo J, Taylor PR, Kontto J, et al. (2014). Effects of α-tocopherol and β-carotene supplementation on cancer incidence and mortality: 18-year postintervention follow-up of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. International Journal of Cancer 135(1):178–185. doi.org/10.1002/ijc.28641
Goodman GE, Thornquist MD, Balmes J, et al. (2004). The Beta-Carotene and Retinol Efficacy Trial: Incidence of Lung Cancer and Cardiovascular Disease Mortality During 6-Year Follow-up After Stopping β-Carotene and Retinol Supplements. Journal of the National Cancer Institute 96(23):1743–1750. doi.org/10.1093/jnci/djh320
Brasky TM, White E, Chen CL (2017). Long-Term, Supplemental, One-Carbon Metabolism–Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort. Journal of Clinical Oncology 35(30):3440–3448. doi.org/10.1200/JCO.2017.72.7735
Manson JE, Cook NR, Lee IM, et al. (2019). Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease. New England Journal of Medicine 380(1):33–44. doi.org/10.1056/NEJMoa1809944
Manson JE, Cook NR, Lee IM, et al. (2019). Marine n−3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. New England Journal of Medicine 380(1):23–32. doi.org/10.1056/NEJMoa1811403
NHS. B vitamins and folic acid. nhs.uk
Thomas LDK, Elinder CG, Tiselius HG, et al. (2013). Ascorbic Acid Supplements and Kidney Stone Incidence Among Men: A Prospective Study. JAMA Internal Medicine 173(5):386–388. doi.org/10.1001/jamainternmed.2013.2296
Tucker J, Fischer T, Upjohn L, et al. (2018). Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With US Food and Drug Administration Warnings. JAMA Network Open 1(6):e183337. doi.org/10.1001/jamanetworkopen.2018.3337
Wikipedia. Sibutramine. en.wikipedia.org
Chiou WB, Yang CC, Wan CS (2011). Ironic Effects of Dietary Supplementation. Psychological Science 22(8):1081–1086. doi.org/10.1177/0956797611416253
Wikipedia. Vitamin. en.wikipedia.org
Wikipedia. Dietary Supplement Health and Education Act of 1994. en.wikipedia.org
MRC Vitamin Study Research Group (1991). Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study. The Lancet 338(8760):131–137. doi.org/10.1016/0140-6736(91)90133-A
NHS. About folic acid. nhs.uk