Vitamin C is a water-soluble vitamin that is necessary for many bodily processes. It is involved in energy production, the reduction and storage of iron, the activation of folic acid, the synthesis of collagen and elastin, and the synthesis of several neurotransmitters and hormones. It is also an antioxidant that neutralizes the free radicals that can often damage bodily tissues.
In a recent review of numerous studies of vitamin C, it was reported that vitamin C can reduce the length of the common cold. The review examined the incidence of colds in patients taking preventative doses of vitamin C that were participating in 30 different studies. In the review, vitamin C reduced the incidence of colds in the study patients by 8%. The RDA (recommended daily allowance) of vitamin C is 75mg per day for women and 90 mg per day for men. The tolerable upper limit is 2000 mg per day for women and men. Foods that are high in vitamin C are green peppers, citrus fruits and juices, strawberries, tomatoes, broccoli, leafy green vegetables, sweet and white potatoes, and cantaloupe.