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How Much C Is Enough?
The Recommended Dietary Allowance (RDA) for vitamin C is 75 milligrams a day for women, 90 for men. But these recommendations are based mainly on Cs role in preventing a deficiency diseasescurvyrather than an amount that might promote optimal health and prevent chronic disease.
For smokers, the recommendations jump to 110 milligrams daily for women and 125 for men. Smokers C needs are higher because they are under increased oxidative stress from cigarette smoke, leading to lower blood levels of C.
For such an easy vitamin to get, its surprising to learn that up to 17% of Americans are vitamin C deficient. And nearly one-quarter have depleted blood levels of C, even though they are not clinically deficient. One study found that smokers, people who dont take a multi and African-American men are most at risk for being deficient in C.
To keep blood levels high, you need vitamin C daily. Start your day off with a C-rich fruit or juice, then eat at least 2½ cups of fruits and vegetables to get the recommended 200 milligrams of C.
Research on optimal health suggests that the RDA for vitamin C may be set too low, particularly for women. Some researchers believe intakes of 100 to 200 milligrams are needed to saturate cells with vitamin C, while others believe it takes at least 400 milligrams, an amount thats hard to get without a supplement. Erring on the high side is not a problem, as most evidence points to a maximum safe dosage of 2,000 milligrams a day.
All fruits and vegetables contain some vitamin C, but some more than others. Eating 2 ½ cups of fruits and veggies each day provides about 200 milligrams or more of C.
Source: USDA Nutrient Database, Release 20 (2008)
