Published Apr 7, 2015
By Kelly Kennedy, MS, RD, LDN
Q: I’ve always heard that taking a vitamin C supplement will decrease my risk of catching a cold, and that if I do catch a cold, I can take a higher dose supplement to make it go away. Is this true?
A: The temps outside may be getting warmer, but cold season is still lingering for many of us. It’s a smart idea to stay prepared! In fact, did you know that more than 200 viruses can cause common cold symptoms, such as runny nose, congestion, cough, sore throat, sneezing, headache, and fever? Because colds are caused by a virus, antibiotics are powerless against them, leaving under-the-weather folks desperate for reprieve. Enter vitamin C — the most popular alternative treatment since the 1970s, when Nobel Prize scientist Linus Pauling endorsed the nutrient as a cure for the common cold.
Vitamin C for Cold Prevention
So, will drinking a glass of OJ really stave off the sniffles? Since the ’70s, numerous studies have been conducted to test the effectiveness of vitamin C against colds. Unfortunately, the results have not been overwhelmingly positive. A 2010 Cochrane review of 29 trials, which included more than 11,000 participants, found that regularly taking vitamin C had no effect on how often people got the common cold. However, regular intake of vitamin C may offer a decent reduction (up to 50 percent) in risk for the common cold for people who are engaged in short periods of extreme physical stress, which is great news for marathon runners and avid skiers (myself not included).
The conclusion? Regular supplementation of vitamin C in the general population is not justified.
Once You Have a Cold
The jury’s still out on the impact vitamin C has once you become ill. For now, the research seems to suggest that if you regularly take a vitamin C supplement and you get a cold, the length of the cold may be slightly shorter than it would have been otherwise. However, there seems to be no effect if you do not regularly take a vitamin C supplement, and begin taking large doses after the first signs of a cold.
The Bottom Line on Vitamin C and Colds
Vitamin C acts as an antioxidant in the body, and aids in the formation of collagen (a protein that helps heal wounds and is important in tissue structure). It also helps the body to more easily absorb iron from plant sources. It’s a crucial part of a balanced diet and, as with any nutrient, it’s best to get it by eating a diet rich in healthy foods. Foods high in vitamin C include: citrus fruit, bell peppers, cantaloupe, kiwi, mango, papaya, pineapple, strawberries, raspberries, blueberries, and cranberries.
The National Institutes of Health Office of Dietary Supplements recommend that adult men get 90 mg of vitamin C each day (about the amount of a large orange) and women get 75 mg per day (about the amount of half of a red bell pepper). Most people get plenty of vitamin C from their diet, but if you do choose to add a supplement, stay below the recommended upper limit of 2,000 mg per day for adults. Any more than this can cause side effects such as stomach cramps, nausea, and diarrhea.
If you have a cold, try other natural remedies:
- Drink plenty of fluids (such as water and tea)
- Get plenty of rest
- Take a steamy shower or using a humidifier
- Gargle with salt water
- Apply menthol ointment
- Use saline drops or a neti pot (just be sure to use distilled or filtered water)
If all else fails, I’m still a strong believer in the healing powers of mom’s chicken soup!
Kelly Kennedy is a registered dietitian who has her bachelor’s degree and master’s degree in nutrition. She is also a licensed dietitian and nutritionist in the state of Massachusetts.