Should You Take Your Vitamins?

Will daily doses of vitamin C really help prevent a cold?

by Brian Dunning

Filed under Alternative Medicine, Consumer Ripoffs

Skeptoid #103
June 3, 2008
Podcast transcript | Listen | Subscribe
Also available in Russian

What do you do when someone in your household catches a cold? If you're like me, you run for the medicine cabinet and start megadosing yourself with vitamin C. Everyone knows this is the best way to stave off a cold. Everyone also seems to think that vitamins are like spinach for Popeye: Whether you need them or not, taking extra vitamins when you don't necessarily have a deficiency is perceived to bestow some sort of super-health, as if you can somehow be even healthier than healthy. If you take any vitamin supplement, and you do not have a diagnosed vitamin deficiency, please listen carefully to the following.

The idea that vitamin C is a wonder drug for preventing colds and other illnesses became widely popular around 1970, due largely to some books written by one of our greatest scientists, Linus Pauling. Along with Marie Curie, Pauling shares the distinction of being one of only two people to receive Nobel Prizes in two different fields. He received his first in chemistry in 1954 for his pioneering work characterizing the nature of chemical bonds. He received the Peace Prize in 1962 for his work warning of the dangers of nuclear weapons proliferation and radioactive fallout. Ironically, it was this type of activism that had almost prevented his being able to travel to Stockholm to accept his first prize: In those days, the United States was in the habit of denying passports to citizens who were sufficiently outspoken against nuclear weapons. Pauling's contributions to 20th century science are inestimable. He described the structure of the atomic nucleus. He was a key player in the theorized, and later proven, helical structure of DNA. He was practically the founding father of the whole science of molecular biology. He was even involved in the development of one of the first commercially available electric cars, the 1959 Henney Kilowatt.

So how is it possible that such an accomplished genius could be fundamentally wrong for much of his career? Let's set aside the notion that a scientifically brilliant mind must always be a rational, objective, and unbiased mind, and look at Pauling's later writings. In 1970, he published a book called Vitamin C and the Common Cold, in which he outlined the concept he called orthomolecular medicine. Orthomolecular means the "right molecule". Its central thesis is that megadoses of vitamin C prevent colds and can prevent or treat other conditions. He expanded this to include cancer when he wrote 1979's Vitamin C and Cancer. In 1986 he published How to Feel Better and Live Longer, in which he broadened all his concepts and claimed that megadoses of all vitamins would improve your overall health, would slow aging, and increase your enjoyment of life. It's important to note that orthomolecular medicine is not a concept shared by responsible doctors or dietitians; it is squarely in the alternative medicine camp. The Mayo Clinic tested Pauling's claims about treating cancer with vitamin C in three different randomized controlled trials, all of which showed no beneficial effect. Pauling spent years passionately trying in vain to discredit these trials, which created something of a gap between himself and mainstream medical science. In fact, despite the staggering importance of his earlier contributions to science, by the end of his life Dr. Pauling was largely regarded as a crank by his former colleagues, much like Nikola Tesla, by some accounts.

There have been at least 30 well-performed controlled trials to find out whether vitamin C at various dosages can prevent colds, or reduce their severity. What these studies have determined is that vitamin C has no preventive value at all; you're just as likely to catch a cold if you take daily megadoses as you are if you take nothing at all. A few of these trials did find small reductions in the severity or duration of the colds, but most trials did not show even this small effect.

I know all of this, but every time the cold and flu season comes around, I still catch myself eyeing that vitamin C bottle. I'm like the jungle native who's been baptised by the missionaries, but whenever the volcano erupts, I still run to the stone pagan idol. My own experience is that I've never gotten sick whenever I've been regularly taking vitamin C. And, this is the same experience reported by a lot of people. So it would seem that our own experiences support what Dr. Pauling was saying, and disputes what testing has revealed. We all have to believe our own eyes, and to believe our own first-hand experiences, right?

Well, yes, but we also have to understand the way our brain interprets our experiences. Practically the whole reason for the science of psychology is that what we think and feel is not necessarily 100% translated to the real world. It's certainly possible to misinterpret something someone tells us, so isn't it also possible to misinterpret other experiences? Well, we do misinterpret our own perceptions and our own experiences, and we all do it every day. Is it possible that you did have a minor cold, but since you were taking vitamin C the thought never entered your mind that it could be a cold? Maybe you just attributed it to seasonal allergies, and even though the facts are that you got a cold while taking vitamin C, your own perception confirms that the vitamin C was 100% effective. Is it possible that you don't exactly remember the number of colds you got last year? Of course it is. And, perceptual biases aside, is there any chance that you wouldn't have happened to catch a cold anyway? Of course that's possible too.

Thus, you can't reasonably consider your own experience as evidence that vitamin C is effective against colds. Your only evidence is anecdotal and unreliable due to a variety of perceptual phenomena; and in any case your own test of vitamin C was an uncontrolled, unblinded test with no statistical validity.

But you're not alone. A lot of people believe that vitamins will prevent colds, and the alternative medicine industry has always been quick to capitalize on this. There's a product called Airborne that is a repackaging of an ancient Chinese remedy called yin chiao. It contains undisclosed quantities of a few herbs and vitamins, including vitamins A, C, and E. Their marketing slogan is "Invented by a schoolteacher", which for some reason people view as meritorious, even though all it really means is "Invented by someone with no medical background whatsoever". For a decade they made false advertising claims that their product could prevent and treat colds. Sure enough, eventually the law caught up with them, and fined them $23 million and ordered them to refund the purchase of anyone who ever bought their product. They're still in business, although they now make the claim that Airborne boosts your immune system. As any doctor will tell you, "immune system boosting" is pure pseudoscience. It's medically meaningless, but that's a whole other subject that we'll examine in a future episode.

Not only is there a lack of evidence that these products have any beneficial effects, there is well established evidence that they can be dangerous. If you take the recommended dose of Airborne to fight a cold, you're taking enough of a vitamin C overdose to put yourself at risk of kidney stones. Although the popular folk wisdom teaches that extra vitamins are simply excreted in the urine, this is largely untrue. Vitamin overdosing is called hypervitaminosis or vitamin toxicity, and can lead to serious effects. Hypervitaminosis A can lead to birth defects, liver problems, osteoporosis, skin problems, and hair loss. Hypervitaminosis D can cause dehydration, vomiting, anorexia, hypercalcemia and kidney damage including kidney stones. Hypervitaminosis E can lead to blood problems including high cholesterol and can act as an anticoagulant. It should be noted that to be at risk of any of these conditions, you would need to significantly overdose over a long period of time. Brief or modest overdoses of any vitamin supplement are unlikely to cause problems. Interestingly, vitamin K is an effective treatment for many hypervitaminosis toxicity conditions.

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A common criticism I receive is "Why should I believe you, when upstanding companies like Airborne, and practically everyone else in the world, tells me I should take vitamins?" Well, I hope you don't trust me. I hope that if you're truly interested, you'll ask a medical doctor. And by "doctor" I don't mean a naturopath, a health food store clerk, or anyone else who's in the business of selling you vitamin supplements. The simple fact is that nearly everyone who eats anything close to a balanced diet in any developed country is extremely unlikely to have a vitamin deficiency. Thus, there is no plausible benefit to vitamin supplementation for general health or wellness.

Brian Dunning

© 2008 Skeptoid Media Copyright information

References & Further Reading

Aronson, V. The Dietetic Technician: Effective Nutrition Counseling. Westport: AVI Pub Co., 1986. 65, 85.

Barrett, S. "High Doses of Vitamin C Are Not Effective as a Cancer Treatment." Your Guide to Quackery, Health Fraud, and Intelligent Decisions. Quackwatch, 23 Oct. 2008. Web. 10 Jan. 2010. <>

Bhagavan, N.V. Medical Biochemistry, Fourth Edition. San Diego: Academic Press, 2002. 901-928.

Editors. Harvard Health Letter. Boston: President and Fellows of Harvard College, 2011. 4.

Goertzel, T., Goertzel, B. Linus Pauling: A Life In Science And Politics. New York: Basic Books, 1995.

Taylor, Eric N., Stampfer, Meir J., Curhan, Gary C. "Dietary Factors and the Risk of Incident Kidney Stones in Men: New Insights after 14 Years of Follow-up." Journal of the American Society of Nephrology. 31 Dec. 2004, Volume 15, Number 12: 3225-3232.

Weichselbaum, E. "Can supplements help prevent or treat a common cold?" Nutrition Bulletin. 1 Mar. 2010, Number 35: 26-29.

Reference this article:
Dunning, B. "Should You Take Your Vitamins?" Skeptoid Podcast. Skeptoid Media, 3 Jun 2008. Web. 31 Aug 2015. <>


10 most recent comments | Show all 89 comments

@Mud--Once again you make my heart pound with joy.

@Dick--Actually, you're wrong. There are a lot of doctors of all types who are investigating dietary medicine. For example, a prestigious American doctor recently announced that adequate amounts of vitamin D are absolutely necessary for heart health, and that a recent study had discovered that far too many people weren't getting sufficient vitamin D. Some because they don't get enough sunshine. Some because they're vitamin D resistant.

Doctors who deal in celiac disease, for another example, deal almost exclusively in dietary medicine. They use modern medical techniques to diagnose the issue, and then dietary techniques to provide relief.

The difference is that there are diseases and problems that you can't fix with diet. People ate a lot healthier 100 years ago, and exercised a great deal more. But they died in massive numbers any time a bacteria came along, because they couldn't fix it with diet and exercise.

There needs to be a balance.

HistoryTalking, The Real World
January 23, 2013 4:55pm

I wouldnt be that quick in stating that folk ate a lot healthier 100 years ago.

I would suggest that a hell of a lot of westerners over eat a healthy diet suitable to us humans.

I have spent a weekend with a fallacy generator and have heard every ludicrous claim on diet and apricots repeated ad nauseaum. Thankfully Pho chased him off for interfering with the good work that the clan generates at the slave farm

Mud, Pho's Slave palace, Gerringong the Brave, NSW
March 14, 2013 1:46am

This has nothing to do with any above posts. Most of your podcasts on health seem to side with doctors; don't most family practitioners recommend a daily vitamin to many or most patients? I was raised to distrust the medical establishment, and never took vitamins. I completely trust doctors, and as an adult, started taking a daily multi-vitamin after my doctor recommended it. Is this an unessesary waste?

Adam, Boulder
July 2, 2013 2:21pm

Actually, it's a misconception that the diets of people in the past were necessarily more nutritious or healthier. 100 years ago, there was an epidemic of pellagra, a vitamin deficiency, in the American South, where poor people, prisoners, and orphans ate nothing but corn mush. In the first half of the 20th century, 100 thousand people died and 3 million more got ill with this condition until they began fortifying corn meal with vitamins. (
Now, with fortified food and more varied diets, no one in the US dies of malnutrition unless they're neglected dependents or anorexic.

Modern diets in the USA can also be very unhealthy, its' true, but it's not because of any lack of nutrition, but rather due to excess of calories.

Kat-chan, Olywa
September 1, 2013 2:18pm

Its one of those discussions that doesnt need examples Kat-chan.

Sadly, when in glut, gluttony is the main disease.

Microwave Dizzy, Gerringong Big Ill. USO
September 13, 2013 5:49am

It's interesting that a skeptoid chose to mention some vitamin C studies that found no benefits to megadoses supplementation of Vit. C to discredit ALL vitamin supplementation. Really? Is that how a skeptic debunks pseudo-science?
Next time you have a cold try supplementing with zinc for the duration of the cold and see what happens.
And next time your doctor tells you you have arrhythmia and tries to cram down your throat dangerous prescription meds, try supplementing with MAGNESIUM CITRATE OR GLYCINATE instead and watch what happens .
Oh, yes, I forgot, but if your cold disappears and your heart returns to normal sinus rhythm, it was not the Vitaminc C or Magnesium that helped, no, it was because you just imagined you had a cold and arrhythmia! and you better believe those studies and not your own experience because your own experience is anecdotal an unreliable!
Yes, right. You better believe those studies and stay away from all these dangerous vitamin and minerals despite what your own experience tells you.
Thank you skeptoid for teaching me to believe all those studies and distrust my own experience. That's the way to navigate in this trustworthy world. Thank you!

Didi, New York
November 8, 2013 8:32am

This short youtube:

is rather precise in why, in fact, multivitamins are a very good, if not crucial, idea.

JR, Stockholm
February 25, 2014 4:10am

Great article, with one massive error. The Henney Kilowatt is far from one of the first commercially available electric cars. Around the 1900s, almost 40% of vehicles in the us were electric. It was an electric car in 1899 that broke the 62mph (100km/h) speed barrier. Many cities had electric cab fleets. And, of course, there was the Detroit Electric, able to go 375 miles in 3 days, and 83 miles on one charge.

Also, for motor buffs: around this time Ferdinand Porsche designed and built an all-wheel drive (in wheel hub) electric car that also set several records.

David, Minnesota
February 25, 2014 8:13am

I reckon the supplements industry is one of the great rip-offs of the modern world.These supplements are not properly regulated so one does not know what they really contain,and if they did contain what they claim,probably would not do you any good anyway.

nick cox, singapore
February 25, 2014 8:02pm

While this is cool, I'd really like to see a followup on vitamin H (or Biotin) which is sold as a supplement to help with hair, skin, and nails.

There's a LOAD of information out there, but as a lay person sorting studies gets a little hard. It seems like it's "not bad for you, but also probably doesn't do anything" is this true?

MrD, Providence RI
March 26, 2014 9:52pm

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