Vitamin C for Colds?

Okay, since I talked again about vitamin D last week, why not talk about a few more vitamins? What about Vitamin C for colds? Should it be taken as prevention, or as a cure? Can you get too much?


Honestly, the medical literature has gone back and forth on vitamin C and colds. Large studies have shown little benefit in prevention, unless you are an extreme athlete or living in very cold temperatures. For people in those categories, it appears Vitamin C in doses greater than 200mg per day can indeed decrease the frequency of upper respiratory infections. Skiers, perhaps you should start your morning with a big glass of juice instead of hot chocolate or coffee!

Where there does seem to be benefit across the board is when Vitamin C (again in doses greater than 200mg per day) is taken once you develop cold symptoms. At that point, Vitamin C seems to decrease the duration of symptoms.

How much is too much? The RDA is 75mg for women and 90mg for men. Supplements come in 100, 200 and 500mg tablets, plus I'm sure you've seen and maybe taken the mega-dose vitamin C packets that come in powder packets. These typically have 1000mg of Vitamin C (along with a handful of other vitamins). While C is water-soluble, which means that "extra" vitamin C not used by your body will simply exit in your urine, it is possible for megadoses (often exceding 2000mg per day) to cause kidney damage by precipitating a special type of stone formation in the kidneys.

What type of Vitamin C is best? As always, you are better off getting your vitamin C from whole foods-fruits like berries, red peppers, guavas, kiwis, and yes, oranges. You will NOT overdose from these natural sources!

BOTTOM LINE: Vitamin C may help shorten the duration of a cold, and could help with prevention for those in cold climates or if you will be doing "extreme" physical activity.