Research on vitamin D supplementation and health effects

Supplementing with Vitamin C enhances the body's ability to absorb iron, promotes wound healing, and helps the repair and maintenance of healthy bones, teeth, and cartilage (Wax, 2015). Other benefits of Vitamin C supplementation may include shorter durations of common colds, and "somewhat milder symptoms," although there is no evidence that supplementation reduces the risk of catching a cold (Wax, 2015). Vitamin C supplementation may be especially helpful for smokers, many of whom have low levels of Vitamin C because smoking cigarettes depletes Vitamin C from the body (Erlich, 2013). Low levels of Vitamin C are associated with a number of adverse health effects; low levels of Vitamin C increases the risk of high blood pressure, arteriosclerosis, gallbladder disease, stroke, and even some cancers (Erlich, 2013). Anemia, bleeding gums, dry hair and skin, and swollen joints may all be indications of deficiency (Wax, 2015). Therefore, supplementation might decrease the risk for these and other conditions.

Because Vitamin C is water soluble, it does not build up in the body and adverse side effects are "very rare," (Wax, 2015). Therefore, there is no officially high upper intake level but high doses -- above 2000 mg per day, can cause stomach upset or diarrhea (Wax, 2015).