Everyone hates being sick. And when our offices and clinics are packed with sneezing, sniffling, coughing families, we desperately wish there was something effective we could recommend that would avoid the colds and coughs. Some may tell you that taking vitamin C or echinacea or zinc will keep you from getting a cold. Unfortunately, the science does not suggest that any of these things are going to help you very much.
Vitamin C
Vitamin C was discovered back in the 1930s, and people have been suggesting that it helps alleviate respiratory illnesses and colds ever since—and we can’t blame you for believing that it works. After all, two-time Nobel Prize–winner Linus Pauling thought the same thing and told everyone to load up on vitamin C. Are we claiming to be smarter than a Nobel Prize winner? No. (Well, maybe Aaron.) What Dr. Pauling did in the 1970s was exactly what we are doing now—he looked at the scientific studies of vitamin C and said that the results indicated that vitamin C worked to keep people from getting colds. The advantage that we have over Dr. Pauling is that many more studies have been done since that time. When the studies are combined, the results tell us much more definitively that taking vitamin C every day will not prevent a healthy person from getting a cold.
However, if you run marathons every weekend, routinely plummet down Alpine slopes, or engage in subarctic military training exercises, then be our guest and take vitamin C regularly. Only those individuals exposed to short periods of very extreme physical stress, extremely cold conditions, or both, seem to have less of a chance of getting colds if they take vitamin C regularly.
What about all the people out there who aren’t super-human athletes training in extreme temperatures? If you take vitamin C every day, your cold might be a little shorter (we’re talking hours shorter—not days). But if you start taking vitamin C after you feel sick, your cold will not be any shorter or any less severe (based on the results of eleven studies of more than 6,000 people). Most studies that examine vitamin C efficacy are randomized, placebo-controlled trials. In a review that combined thirty of these great studies and included more than 11,000 people, taking 200 mg. of vitamin C or more per day was shown to be completely ineffective in preventing sickness. So, for the average Joe, there’s no need to bother with the extra vitamin C.
Echinacea
Echinacea has been so widely touted as a cold treatment that it has become one of the most commonly used herbal products. The science and studies of echinacea leave us with some questions. What is clear to us is that echinacea does not cure colds. Colds are caused by respiratory viruses, and there is no science to suggest that echinacea gets rid of the viruses that cause colds. However, it is possible that echinacea might shorten the lifespan of your cold. The conclusion of a 2006 Cochrane Systematic Review was that echinacea does not work. When the Cochrane Systematic Review looked at sixteen studies of the herb, echinacea was no better than a sugar pill at preventing colds. One of the studies was published in the prestigious New England Journal of Medicine; doctors examined almost 400 volunteers either taking echinacea or taking a sugar pill, and found that the echinacea did not change the severity of your cold systems or how the infection progressed. Some of these studies did suggest that echinacea works to shorten colds in adults when taken at the very first sign of a cold. In children, echinacea was not found to prevent or shorten colds.
The research didn’t stop there. After the Cochrane Systematic Review was published, two other groups of researchers tried to compile newer studies to answer the question. Because many of the studies have used different techniques, it is hard to compare the results from one study to another. One group looked at studies where researchers actually put gobs of the cold virus right into the study participants’ nostrils and then checked to see if the herb did anything to stop the individuals from getting sick (doesn’t that sound like fun?). Echinacea didn’t work in those studies.
In 2007, yet another group of researchers examined existing studies, and they concluded that echinacea works. They looked at fourteen studies, and decided that echinacea reduces your chance of developing the common cold and shortens how long you experience cold symptoms by almost a day and a half. Unfortunately, other researchers have criticized this study and don’t agree with its conclusions. The researchers combined studies that might be too different from each other to put together—they tried to compare apples and oranges. We are not necessarily saying this study is wrong, but we do think that it might not give us the best answers and so we are not yet convinced that echinacea really works. Echinacea is not the cure to the common cold, but it may help you feel a little better.
Zinc
Once you’ve given up on the vitamin C and the echinacea, you probably decided to try zinc. Unfortunately, there is no evidence that zinc will cure your cold.
The results of zinc studies have been very inconsistent. Some studies have found that zinc lozenges are helpful and some say just the opposite. In a systematic review that examined fourteen of the best zinc studies, half of those studies said that the zinc did nothing at all, and half of the studies reported that the zinc helped. How do we decide which studies to believe? The quality of the studies was evaluated using a set of eleven strict criteria. Only four of the studies met all eleven of these criteria and could be called well designed. Looking only at the four well-designed studies, two reported no effects from zinc lozenges, one reported no effect from zinc nasal spray, and only one reported a positive effect. So, three of the four good studies did not find zinc to be effective.
The one good study that did show a positive effect for zinc was a study of zinc nasal gel, which was found to improve your cold symptoms and how long they last. The only problem—and it’s a big one—is that putting this zinc nasal gel in your nose ultimately resulted in a $12 million settlement in 2006 from 340 lawsuits, claiming that the zinc nasal gel damages the sense of smell for users. Unless you are willing to give up your sense of smell (and your sense of taste, which goes with it), don’t put zinc in your nose!
You also might be interested to know that edible zinc (zinc lozenges) often don’t taste very good. Plus, the most common side effect of zinc lozenges is nausea. If you can stomach the wretched taste and the sick-to-your-stomach feeling, even then zinc only has a small chance of helping you feel better. And the two best studies of zinc lozenges showed that it won’t help your cold at all. We suggest you ditch the zinc.