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Vitamin C & Cold Prevention: Helpful or Hopeless? 



By Akhila Yadalam








November 13, 2008

Introduction: What is the “Common Cold?”

Sneezes, sniffles, runny noses, sore throats, congestion, persistent coughs…the “common cold” has caught us all. Scientifically speaking, the “common cold”, or acute viral nasopharyngitis, is a highly contagious, viral infectious disease of the upper respiratory system, primarily caused by certain types of viruses, such as rhinoviruses or coronaviruses. ( Basically, it’s not something anyone looks forward to having. Though symptoms generally cease after about a week, they can last for up to two.  

In the United States, the common cold leads to approximately 500 million cases per year and 100 million doctor visits, leading to a cost estimate of $7.7 billion dollars a year. Moreover, we spend almost $3 billion dollars on over-the-counter drugs and another $400 million on prescription drugs for symptom relief. What’s even worse is that over 1/3rd of the patients who saw doctors received prescription medicines, which contributes to  pointless costs and also increases antibiotic resistance with overuse. When the economic impact of cold-related work loss is added to the mix, the total impact of the “common cold” in the US reaches almost $40 billion dollars annually! (

How Do We Catch It?

Is your mom still telling you that you’ll catch a cold when you go out in the cold weather with wet hair or without warm clothing? Well, she’s wrong. Colds are caused by infection, which cannot be caught from cold weather. People mainly get colds from being in contact with other people who have colds. The germ has to be directly given to you or has to be on something that you touch. ( These viruses can also be transmitted via air. When droplets containing the viral particles are exhaled into the air by a person with a cold, the virus can be spread to others. If the droplets touch the eye, nose, or mouth of the other person, he/she will be exposed to the virus and becomes susceptible to it. ( is Vitamin C?

Vitamin C, also known as ascorbic acid, is an essential nutrient for the human body. Because we do not have the ability to produce it on our own, we must obtain Vitamin C through our diets. This water-soluble vitamin has numerous biological roles, functioning as an important antioxidant, and as protection from LDL cholesterol from oxidative damage.  Vitamin C also appears to have an effect on wound healing, lowering blood pressure, and preventing heart attacks, in addition to others health problems. Sources of Vitamin C include citrus fruits, broccoli, red peppers, strawberries, potatoes, and parsley. (


The RDA, or recommended daily allowance, for Vitamin C is 75 mg per day for women and 90 mg per day for men. The RDA value is the dietary intake level that is sufficient to meet nutrient requirements of 97-98% of healthy individuals. According to nutritional surveys taken in April, 2000 by the Institute of Medicine (National Academy of Sciences), around 11% of women and 21% of men in the US do not meet the recommended intakes of Vitamin C. (

Vitamin C: Claim to Fame, how exactly did Vitamin C get linked to cold prevention?


The sole two-time, undivided, Nobel Prize winning chemist in history, Linus Pauling, was the first to make the connection. In 1970, he wrote the book Vitamin C and the Common Cold which popularized the concept that this vitamin could prevent one of the most common illnesses affected by the population. Though literary critics argued that the book was accompanied by little scientific backing and lacked substantial evidence, the book’s message stuck and the idea still resonates today. (


Although Pauling’s instinct was accurate, basing his notion on the fact that Vitamin C strengthens immune functioning and can therefore be seen as a preventative method for the contraction of colds, many doctors have performed clinical studies on the correlation between Vitamin C intake and cold prevention and the data is still being debated upon (Wintergerst et. al, 2005). Dr. Michael T. Murray, author of Natural Alternatives to Drugs, writes, “While the vitamin C studies have consistently demonstrated results superior to over-the-counter cold medications, manufacturers of Vitamin C products are prevented from making any claims for their product, while the makers of OTC common-cold medications spend hundreds of millions of dollars brainwashing the American public into believing these products are the answer to the common cold." (


Does Vitamin C have any effect on the prevention of the “common cold?”

Public Outcome: Products & Popular Belief

Companies never miss a chance to capitalize on a situation, especially health situations. Once word was out that Vitamin C could possibly prevent and/or treat colds, the mass production of supplements began. Two of the most common products of this belief are Airborne and Emergen-C.


Airborne is a dietary supplement that claims to prevent colds by supporting the immune system through the product’s combination of 17 vitamins, minerals, and herbs. Airborne contains 1000 mg of Vitamin C, 1667% of the recommended daily value. There are 11 different kinds of Airborne, ranging from the original version to the night-time version to a soft-chew version. The product also comes in three flavors, Original Zesty Orange, Lemon-Lime, and Pink Grapefruit. (


Emergen-C also contains 1,000 mg of Vitamin C, in addition to 32 mineral complexes and B Vitamins. Emergen-C is a powder that is mixed with water, and it comes in various flavors as well. With a slogan of “Feel the Good”, the promotion tactics of Emergen-C are upbeat and extremely unscientific, appealing to a teenage audience. (


As for popular belief, according to a recent survey taken in January, 2002 as part of a clinical study that tested the relation of Vitamin C supplementation with the number of colds, days sick, and the severity per subject, 67% of the general public believed that taking Vitamin C reduced cold symptoms (Spiers, 2002).


What Does Research Show?


Scientific research has a lot to say on this controversial topic. Countless studies have been performed, and both hypotheses have been argued and tested for. In one such study, the daily oral dosage of 0.2 grams of Vitamin C and whether or not it reduced the incidence, duration, or severity of the common cold when used as either a continuous prophylaxis or after the onset of the cold symptoms was tested for, and compared to that of a placebo (Hemilä et. al, 2007). The study size was enormous, having thirty trial comparisons involving 11,350 study participants. When compared to the placebo trials, however, no significant effect was observed. The failure of the Vitamin C supplementation to decrease the occurrence of colds indicates that a routine “mega” dosage of the vitamin is not justified. On the other hand, evidence did suggest that Vitamin C could be taken in large quantities for people exposed to brief periods of rigorous physical exercise or cold-like environments.

In another trial that also tested ascorbic acid in the treatment of the common cold, participants were given 1 gram tablets of Vitamin C and asked to record their symptoms. Four tablets were taken per day for a total of 24 days. Volunteers were asked to begin taking the Vitamin C tablets as soon as they experienced any warning signs of the “common cold.” The results of this experiment showed that Vitamin C had no effect on lessening the symptom severity or duration, or from stopping the cold from returning (Tyrrel et. al, 1977).

In another investigation that was conducted over a period of 5 years, participants were given Vitamin C capsules of either a low dosage or a high dosage, and instructions were given to them as to how to take the tablets. The subjects were monitored at a public health center every three months where nurses observed their health. Additionally, their participation in the study was monitored by counting the number of unconsumed tablets. This study showed that the incidence of contraction of the common cold was lower in the participants who took the higher dose of Vitamin C. However, no reduction in symptoms or severity was shown amongst the Vitamin C users (Sasazuki et. al).

The Final Verdict: Does it Work?

So, does Vitamin C have any effect on the prevention of colds? The answer is no! The use of Vitamin C in the prevention and treatment of the common cold and respiratory infections remains controversial, despite all of the studies that have been performed. The research found showed that Vitamin C did very little to reduce the symptoms, length, and severity of colds among the sample populations. One study, however, did find that the risk of catching a cold could lower among people whose bodies were under severe physical stress, like soldiers or marathon runners. For the average person, though, a Vitamin C supplement or extra glass of orange juice isn’t going to do much.

Though the “cold-killing” idea may not be true, there is no reason to erase this belief as Vitamin C is an essential to the human body and is not posing any serious public threats. Some studies have even shown that the antioxidant properties of Vitamin C have decreased the prevalence of some cancers. Ultimately, you should drink your orange juice or take your Vitamin C, but don’t do it under the pretense that you are protected from colds!




Harri, H., Elizabeth, C., Barbara, T., & Bob, D. (2007). Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, 3, 1-5. Retrieved Oct. 10, 2008.


Sasazuki, S., Sasaki, S., Tsubono, Y., Okubo, S., Hayashi, M., & Tsugane, S. (2006). Effect of vitamin C on common cold: randomized controlled trial. European Journal of Clinical Nutrition, 60, 10,11,12. Retrieved Oct. 10, 2008.


Spiers, P. (2002). On the Prevention of the Common Cold: No Help from Vitamin C. Epidemiology, 13(1), 5. Retrieved Oct. 10, 2008.


Tyrrell, D., Craig, J., Meada, T., & White, T. (1977). A trial of ascorbic acid in the treatment of the common cold. Journal of Epidemiology and Community Health, 31(3), 189, 190, 191. Retrieved Oct. 10, 2008, from the PubMed database.


Wintergerst, E., Maggini, S., & Hornig, D. (2005). Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Annals of Nutrition & Metabolism, 50(2), 87, 88. Retrieved Oct. 10, 2008, from the PubMed database.



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