How Much Vitamin C Can I Take A Day?

Humans are among the few mammals incapable of creating their own vitamin C and must receive it through diet or supplementation. Vitamin C, also called ascorbic acid, is a potent antioxidant linked to protecting the body against environmental pollutants. Vitamin C is also thought to strengthen the immune system and support the formation of skin, bones, teeth and blood vessels. Theories conflict regarding how much vitamin C is necessary and safe on a daily basis.

Megadose Recommendations

Dr. Linus Pauling published a 1970 book entitled "Vitamin C and the Common Cold" in which he advocated daily megadoses of vitamin C of up to 10 g. Through a series of other books, Pauling continued to argue his case despite receiving criticism for his claims. Many modern practitioners support this method of treatment, and because vitamin C supplements are readily available, many people follow Pauling's controversial advice.

FDA Recommendations

The FDA sets dietary standards, called recommended daily allowances, based on the body's minimum requirements for nutrients. The RDA for vitamin C is set at 90 mg for men and 75 mg for women. Critics of these standards, however, state that this is the bare minimum the body needs to prevent deficiency diseases such as scurvy and is not enough to maintain optimum health.

Expert Insight

Doctors Ronald Klatz and Robert Goldman in their book "The Official Anti-Aging Revolution" recommend 2,000 mg for long-term use and 3,000 mg for short-term use as maximum daily dosages. The doctors warn that people with heart and kidney disease or a history of kidney stones should consult their doctor before beginning supplementation with vitamin C.

Potential Copper Deficiency

A study published in the "American Journal of Clinical Nutrition" found documented that high levels of vitamin C reduced the body's supply of copper. Copper is a vital mineral used to control cholesterol and the deficit in copper caused by vitamin C brought about an increase in cholesterol. However, this study was published in 1981 and did not state what constitutes a high does of vitamin C. Despite the age of this study, even proponents of vitamin C megadoses recommend coupling it with a copper supplement.