Does Higher Doses Of Vitamin C Really Lower Your Risk of Catching a Cold?

Does high doses of vitamin C really lower your risk of catching a cold?

The sniffles are inconvenient any time of year, but you’re more likely to catch a cold during the chilly fall and winter months. Why are stuffy noses and sore throats more common in the winter? Scientists used to believe the risk of getting an upper respiratory infection went up because people spend more time indoors in close quarters when it’s cold. However, more recent research shows cold viruses actually replicate more efficiently inside your nose when it’s cooler. So, these nasty viruses can gain a better foothold as the temperature drops.

The worst time to have a cold is when? Around the holidays, of course. It’s hard to be of good cheer when your nose is stuffy and your head feels the size of a bowling bowl. You might wonder what you can do to lower your risk of catching a cold this winter?  The idea of taking a vitamin C supplement probably comes to mind. It was Linus Pauling who proclaimed that high doses of vitamin C lowers the risk of colds and he stood behind this idea his entire life. In fact, he took high doses of vitamin C himself to ward off colds. Wonder how many colds he actually got? He never revealed this information.

Should you follow in Linus Pauling’s footsteps and take vitamin C? Does vitamin C really lower the risk of colds and upper respiratory infections?

High Doses of Vitamin C For Colds

It’s easy to see why people think vitamin C prevents colds. Vitamin C is a vitamin you need for healthy immune function. Several types of immune cells, including ones that fight viruses, need vitamin C to work properly. But, it’s one thing to say that you need enough vitamin C for healthy immune function and quite another to say you’ll get added benefits if you take more than the recommended amount.

How much vitamin C do you need? Recommendations are to get 75 milligrams of vitamin C daily. This corresponds to the amount most people need to avoid deficiency. Linus Pauling, on the other hand, advocated taking 15 to 20 times this amount each day. To get this, you would need a supplement. Was Linus Pauling right? Can getting a high dose of vitamin C lower your risk of catching a stuffy, sneezy cold virus? Back in the 1970s, a study found that kids living in the Alps got fewer colds when they took 1,000 milligrams of vitamin C each day. Unfortunately, subsequent research failed to show significant benefits, at least in terms of prevention.

More optimistically, some research showed taking vitamin C when you first feel cold symptoms coming on MAY shorten the duration of symptoms. These studies suggest that you may recover a day or two faster if you take a vitamin C supplement. It’s not exactly curative but, depending on your perspective, it might be worthwhile. Other research shows that supplementing with vitamin C as soon as cold symptoms develop may reduce the severity of the symptoms.

More recently, a meta-analysis of more than 50 well-conducted studies looking at vitamin C and colds yielded some interesting insights. It showed that supplementing with vitamin C doesn’t lower the incidence of the common cold in healthy people. However, in those who did strenuous physical labor or are exposed to extreme cold, vitamin C supplementation cut the number of colds by half. So, if you work in a very cold environment or plan on running a marathon, you might consider supplementing with vitamin C short-term to avoid colds. To get the benefits, you have to supplement beforehand – not after the symptoms develop.

All in all, the evidence that vitamin C prevents colds for the average person Is weak. However, boosting vitamin C MAY reduce the severity of symptoms and shorten their duration by a day or two.

Why It’s Better to Get Vitamin C from Diet

Although the benefits of taking high doses of vitamin C for cold prevention aren’t overly compelling, it’s important to get enough of this antioxidant vitamin for your health. A deficiency of vitamin C, which was once common, leads to a devastating and fatal condition called scurvy. As you know, many fruits and vegetables are an abundant source of vitamin C. Of the two, eating fruit is a more reliable way of meeting your body’s vitamin C requirements. That’s because cooking vegetables destroy some of the vitamin C inherent in these foods.

The benefit of getting vitamin C from diet, rather than supplements, is you get an additional “perk” – the natural flavonoids so abundant in vegetables and fruits. Dietary flavonoids may be more important than you think when it comes to keeping colds in check. A study from the University of Auckland found that these compounds, present in fruits and vegetables but also cocoa, red wine, and green tea, have potential activity against cold viruses. This study showed adults who consumed more flavonoids or took flavonoid supplements were 33% less likely to develop the common cold.

Some of the best sources of vitamin C and flavonoids are:

·       Papaya

·       Broccoli

·       Strawberries

·       Pineapple

·       Kiwifruit

·       Citrus fruits

·       Cantaloupe

·       Cauliflower

·       Red peppers

·       Green peppers

Remember, cooking cauliflower or broccoli, especially using high heat or large amounts of water, may destroy a significant quantity of a food’s vitamin C. That’s why it’s a good idea to include some raw food sources of vitamin C in your diet.

Is It Safe to Take Vitamin C Supplements?

There’s really not enough evidence to support taking vitamin C as a supplement for cold prevention. Plus, taking high doses of vitamin C is linked with side effects such as nausea, stomach cramps, and diarrhea. High doses of vitamin C also increase the risk of kidney stones. Another concern is that at high doses, vitamin C can have “prooxidant” activity and potentially trigger the formation of cell-damaging free radicals, even though vitamin C has antioxidant activity at lower doses. More isn’t always better when it comes to vitamins and minerals. Fortunately, vitamin C is water soluble, so your kidneys excrete the excess.

The Bottom Line

Make sure you’re getting ENOUGH vitamin C, at least 75 milligrams a day, but get it from fruits and vegetables rather than a supplement. By doing this, you’ll get the benefits of the flavonoids in these foods and you’ll avoid the potential side effects of taking vitamin C supplements and it’s unlikely you’ll develop toxicity. On the other hand, too much of one nutrient may impact the function of others. That’s why it’s best to keep your intake balanced. Make sure you’re getting enough vitamin C but get it from healthy foods rather than supplements.



WebMD. “Why Are Colds More Likely in the Winter?”

Oregon State University. “Vitamin C”

Med Monatsschr Pharm. 2009 Feb;32(2):49-54; quiz 55-6.The University of Auckland. “Flavonoids Reduce Cough and Cold Risk”

World’s Healthiest Foods website.

Cochrane Database Syst Rev. 2013 Jan 31;1:CD000980. doi: 10.1002/14651858.CD000980.pub4.

Medscape Multi-Specialty. “Vitamin C Cures the Common Cold: Fact or Fiction”


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