At the first signs of a cold, many of us pour a big glass of OJ on the assumption that loading up on vitamin C is a surefire way to kick just about any bug. Modern-age nose-blowers may also reach for “immunity boosters” like Airborne and Emergen-C to cure the sniffles. But does vitamin C—and the supplements that tout its benefits—really work to prevent (or cure) the common cold?Researchers have studied the role vitamin C plays in preventing and treating the common cold for more than 60 years. Most experts say there is still little proof that increasing vitamin C intake will help cut down on sick days. Still, the research isn't conclusive. One study found that taking a daily vitamin C supplement reduced the frequency of catching a cold, while another discovered that it has an antihistamine effect that could reduce cold symptoms.Another study found that vitamin C made a big difference in preventing colds in those exposed to brief periods of intense cold or extreme physical exercise (like skiers, military personnel, and marathon runners) but not the general population.
And a different study suggests that upping vitamin C intake could reduce the severity and duration of a cold—and hopefully erase the need for that economy-size tissue box.So it looks like some vitamin C, which is found naturally in superfoods like oranges, bell peppers, and strawberries, certainly won't do us any harm. But what about the massive doses found in products like Airborne and Emergen-C? Created by a schoolteacher in 1997, each tablet of Airborne contains 1,000 mg of vitamin C (equivalent to 11 glasses of OJ) along with zinc, vitamins A and E, selenium, and a blend of herbs including ginger and echinacea. Emergen-C also contains 1,000 mg of vitamin C (1,667 percent of the daily recommended value) and recommends users take it up to two times daily. Each serving also includes B vitamins, zinc, and electrolytes, which is why it claims to enhance energy (without the caffeine crash). While neither of them outright say they can prevent or cure colds (anymore!), the mega doses of vitamin C are generally the reason many cold-sufferers sniffle their way to the supplement aisle.
While there are no product-specific studies testing Airborne and Emergen-C’s effectiveness in preventing and treating the common cold, research that looks at ingredients like vitamin C and zinc can give us some insight into how well the products work. As we've shown, the research on vitamin C is mixed, though many professionals maintain that it's not an effective treatment. Research on zinc also remains pretty inconclusive: Multiple studies suggest that it is not effective at treating colds, though one study did conclude that it may be at high doses. Obviously more research is needed before anyone goes around touting zinc as the latest miracle cure. So it looks like taking these immunity boosters is likely neither seriously beneficial nor harmful. But there are still a few things to consider before overdoing it on the fizzy drinks. Too much vitamin C, for example, can cause diarrhea, nausea, stomach cramps, and kidney stones (the National Institutes of Health suggest that adults consume no more than 2,000 mg of the vitamin each day).
Similarly, too much vitamin A (which is often included in these immune boosters) might do more harm than good. In excess doses (defined by the NIH as more than 10,000 IU per day) can cause dizziness, nausea, headaches, coma, and (in rare cases) death. In other words, it is possible to have too much of a good thing. So when it comes to catching a bug, it’s probably best to save money on the hype and listen to the classic recommendations: get lots of sleep, keep your hands clean, and cook some chicken soup.While regularly consuming adequate amounts of vitamin C may help reduce the frequency of catching colds, there's little evidence that it can actually help prevent or treat sickness once it's already set in. Originally published December 2011. It's our birthday next week and we're celebrating with a HUGE sale. Sign up to get early access and even bigger discounts. Your e-mail is safe with us. We don’t share personal data. Colds suck, and the flu sucks much worse. So the million-dollar question is: what (if any) supplements actually work to prevent or ameliorate the symptoms of a cold?
Vitamin C is marketed as the go-to supplement for preventing and treating colds. A recent meta-analysis took a look at the data. It looked at two different populations: The general public and … Athletes who engage in “periods of severe physical exercise”, such as competitive skiers and marathoners. While regular supplementation did not reduce the NUMBER of colds, it was able to reduce duration (by 8% in adults and 14% in children) and the severity of cold symptoms. That being said, decreases in cold symptoms were very minor. And supplementation after cold symptoms were present did not produce a reduction in cold length or symptoms severity. In an athletic population, daily supplementation produced a 52% decrease in the number of colds. But as with the general population, vitamin C didn’t produce any benefits after symptoms had presented. These effects were most pronounced in athletes that perform regular or acute bouts of intense training. The most common dosage employed during all of these trials was 200 mg, but some did range up to 2,000 mg.
There has been some research indicating very large doses of vitamin C (as high as 8,000 mg) after cold symptoms have manifested may be able to reduce the duration. More studies are needed on these higher dosages. Unlike vitamin C, zinc has shown more promise in lessening the duration of the common cold, when taken within 24 hours of symptom onset. Zinc lozenges were the method most commonly used during studies, and were effective at reducing cold duration at a dose of 75mg. Dosages should be split throughout the day. Zinc is an important component for strengthening your immune system, so if you happen to be susceptible to catching colds, ensuring sufficient dietary intake is a good idea. Athletes or those who sweat a lot may also be more at risk of zinc insufficiency. Studies have also noted that supplementation with zinc lozenges is associated with changes in taste perception and some cases of nausea. These symptoms went away after supplementation ceased. Additionally, zinc nasal sprays have been suspected to cause a loss of smell.
Because there is no data indicating that the sprays are more effective than the lozenges, the sprays are not recommended. Elderberry or Sambucus is known for its antioxidant properties, and has been indicated as a potential treatment for influenza. A few human trials have shown the herb to reduce the symptoms of the flu. But many of these studies had small sample sizes and some were of low methodological quality. If you choose to prepare elderberry yourself rather than supplementing, note that the berries must be properly cooked before ingestion, as they can cause nausea or increase the risk of cyanide toxicity when eaten in an uncooked state. The leaves and roots can also be particularly poisonous and should not be utilized when preparing supplements such as elderberry juice. In contrast to some of the above-mentioned supplements, Pelargonium sidoides appears to be primarily used to reduce the symptoms of the cold or flu rather than as a preventative measure. This herb contains compounds known as Prodelphinidins that can help prevent bacteria from attaching to the lining of the throat and lungs.
A preliminary study has shown that 30 drops three times daily for up to 10 days can reduce the duration and symptoms of a cold. However, these results have yet to be replicated, and further research is warranted to determine if Pelargonium sidoides taken daily would provide any preventative protection. These two supplements get a lot of attention as “immune boosters”. But the available data in regards to the cold and flu are less clear. Echinacea is an herb that has gained popularity for its ability to reduce the risk of upper respiratory tract infections, and it may reduce sickness length if taken daily. However, these results have not proven to be consistent across studies. When examining the trials using Echinacea as a preventative measure, a positive but statistically insignificant trend was observed. Echinacea also has the potential to interact with medications, particularly with immunosuppressive drugs. Consult with your doctor if you’re intending to try this supplement.
Glutamine has also been billed as an immune booster. This supplement can serve an important role in the critically ill, as demand and usage of glutamine increases. Glutamine supplementation may also benefit those that participate in prolonged cardiovascular exercise such as ultra-marathons. Decreased concentrations of glutamine brought about by these long exercise periods may suppress immunological functions. With regards the glutamine's ability to fight off the common cold, the jury is still out. While it’s possible that glutamine could potentially have beneficial effects, quality data examining this question is lacking. Reaching for a supplement or two can seem like a quick and simple method for defending yourself against the cold and flu. But even the best supplements are much less important for cold prevention and treatment than basic fundamental methods like … Eating a healthy and nutrient-dense diet Sleeping enough and managing stress Getting a yearly flu shot