Vitamin C helps more than the common cold
Most people readily associate vitamin C with the common cold. While there continues to be controversy on whether it really protects from colds and other viral conditions, studies have shown that it does.
Many also associate vitamin C with Linus Pauling, a two-time Nobel laureate who conducted a great deal of early research on this vitamin and fought to publicize its benefits. However, almost no one remembers that much of Dr. Pauling’s research focused on the benefits of vitamin C in cardiovascular health.
By definition, a vitamin is something that is essential to life but that our bodies cannot make, so we need to get it from our food. Oddly enough, vitamin C is not a vitamin for most other mammals; their bodies make as much of it as they need through a four-step chemical reaction that uses blood sugar as the raw ingredient.
Humans retain three of the four enzymes needed to make vitamin C, but we somehow lost the fourth one. It would seem that this resulted from an evolutionary change at a time when vitamin C was plentiful in the human diet. According to evolutionary theory, genetic changes carry a survival benefit but may also carry a hidden detriment. These changes spread at times when the benefit far outweighs the detriment – in this case the loss of a key enzyme to make vitamin C.
Complete lack of vitamin C in our diet leads to scurvy and death. The current RDA of 60 mg was established as a level that prevents the development of scurvy. However, is there an optimal need for vitamin C that is far greater than the small amount necessary to prevent scurvy? A few interesting studies suggest this very thing.
In one study (Proc Natl Acad Sci USA, 2000 Jan 18; 97 (2): 841-6), researchers took a strain of mice that had been altered genetically so that they lost the ability to make their own vitamin C. If their diet contained no vitamin C they developed scurvy, just like humans do. However, if they had enough to prevent scurvy but still less than what their bodies would normally have produced, they developed high cholesterol, clogging of the arteries and ultimately heart disease. Could this be exactly what’s happening to many of us?
Another study (Am J Clin Nutr 2004 Dec; 80 (6): 1508-20) might be even more pertinent to humans. Researchers looked at large numbers of people and found no association between intake of antioxidant vitamins in general and heart disease. There was, however, one exception to this: those who took more than 700 mg of vitamin C per day experienced significantly fewer cases of cardiovascular disease.
Does this mean that 700 mg the amount we should all take? If we extrapolate from the amount animals make based on weight, the daily intake that would seem optimal for humans is in the neighborhood of 4,000 mg per day, a far cry from the 60 mg RDA and the 700 mg in the study!
In addition, the amount of vitamin C animals produce goes up dramatically if they are under stress, have a viral illness, or are exposed to a chemical toxin. It would seem that their bodies know something.
There are virtually no risks associated with taking too much vitamin C except for people with rare genetic conditions such as G6PD deficiency. Although rare cases of kidney stones have been reported in people taking high doses of vitamin C, it is doubtful that these two events were linked in any way. When taking more vitamin C than the body needs or is able to absorb, the excess will trigger loose stools. Incidentally, this is one of the most successful natural strategies to correct chronic constipation.
