Written by Patrick Massey, M.D., Ph.D.

“Doctor, should I take vitamin C during the cold and flu season?” If you were to ask 10 doctors this question, you might get 12 different answers.

There is substantial medical research demonstrating that vitamin C is beneficial for viral infections and in preventing pneumonia. At the same time, there is a lot of research suggesting no benefit. These differences may be explained by how much vitamin C per day was used.

Vitamin C is a dietary nutrient that prevents a disease called scurvy. In the 1940s and 1950s, medical research showed high-dose vitamin C to be effective against influenza, leprosy, tuberculosis and even polio. But with the advent of antibiotics, vitamin C therapy was used infrequently and the clinical expertise was gradually lost with each new generation of physicians.

Vitamin C is necessary for a variety of metabolic functions. Besides its role as an antioxidant, it also used in tissue repair, brain chemical production, adrenal function, wound healing, immune function, heart disease, diabetes, lung function, detoxification and cancer prevention.

All animals – except for humans, primates and guinea pigs – make vitamin C. The daily-recommended dose of vitamin C is 500 mg, the minimal amount needed to prevent scurvy. The optimal dose is not known.

However, the average, 40-pound barnyard goat makes 10,000 mg on a daily basis and more than 100,000 mg when stressed. One could postulate that we are under-dosed and that a 170-pound person certainly needs more than 500 mg per day.

So, do we need more than 500 mg of vitamin C during the cold and flu season? The answer is yes. In studies based on 1,000 mg of vitamin C per day, the majority of research indicates fewer and less severe colds. In the research using less than 1,000 mg per day, there doesn’t seem to be any benefit.

What is really interesting is what happens when vitamin C is given intravenously. Vitamin C given intravenously can easily achieve the high blood levels of the goat. In those studies, vitamin C was curative for infectious diseases such as polio.

Intravenous vitamin C also seems to improve healing and stress-related conditions, and some professional and amateur athletes use intravenous vitamin C to minimize fatigue and improve recovery time.

For many of my patients, intravenous vitamin C has proven benefits. High doses of vitamin C orally can cause diarrhea and should not be done in children. Intravenous vitamin C is contraindicated for people with certain enzyme deficiencies and kidney stones and should only be done under the direction of a physician.

Posted December 5, 2008.