Vitamin C is certainly one of the most popular vitamin supplements around. But ask a dozen different nutritionists what an optimal vitamin C dosage should be and chances are, you'll get a dozen different answers.
Human beings are one of the few animals, along with apes, that do not produce vitamin C in their body and must rely on dietary sources. The reason for this has been the subject to much speculation and debate over the years. Some scientists think that it may have stemmed from a genetic mistake related to the diet of early primates millions of years ago, but it is not known for sure.
In any event, part of the argument for megadoses of vitamin C stem from the fact that mammals who are able to manufacture vitamin C produce massive amounts when under extreme stress. This led some scientists to hypothesize that maybe humans need an equally high vitamin C dosage under certain conditions.
Some thirty years ago, Linus Pauling made vitamin C a household topic with his book, Vitamin C and the Common Cold. Dr. Pauling claimed that taking one gram of vitamin C daily would prevent the common cold. At the time, this seemed like an extreme idea, but these days, one gram a day seems like a pretty typical vitamin C dosage for those who take it. Vitamin C supplements are commonly sold in 500mg and 1 gram doses.
Whether he was right or wrong, Dr. Pauling created a new field — orthomolecular medicine — that was based on the premise that nutrients and vitamins should not only be used to prevent deficiency diseases, but could be also used at higher doses to achieve optimal health, and even treat diseases.
The missing piece of the puzzle. At the time that Dr. Pauling presented his theories, science did not know much about the antioxidant network. We now know that many of the benefits Dr. Pauling attributed to vitamin C may actually be a result of its enhancing effects on vitamin E and the other network antioxidants. To his knowledge, vitamin C acted in isolation.
Vitamin C strengthens immune system. We do know that one of the benefits of vitamin C is its function as a critical component of a well-functioning immune system. By strengthening the thymus and lymph glands, vitamin C benefits may reduce the frequency and severity of colds and viruses and bolster the body's ability to resist cancer.
Are there benefits to vitamin C megadoses? As mentioned above, proponents of megadoses (1 gram or more a day) of vitamin C point to the fact that animals that make their own vitamin C can manufacture much more than normal when under stress. Some alternative practitioners routinely prescribe several grams daily to patients suffering from conditions such as heart disease, arthritis, and cancer, and contend that it is helpful either alone or with other supplements.
Is there a consensus on a optimal vitamin C dosage? Despite 30 years of research on the benefits of vitamin C, there is still not any agreement about what the optimal daily amount is. It's most likely that individual needs will vary widely. People who are in poor health and under a great deal of oxidative stress may require higher amounts, but we don't know how much more. Smokers in particular suffer from low levels of vitamin C. Since this is a water-soluble vitamin, there's no need to be concerned with too high a vitamin C dosage, within reason; any excess that you take will just be eliminated in your urine.
Other pages on this website about vitamin C: