Ascorbic acid is better known in everyday terms as vitamin C, and it forms an essential part of our daily diet. Indeed, doctors recommend that adult men take at least 90 mg of vitamin C per day while, for adult women, the recommended intake is 75 mg per day.

Vitamin C has many therapeutic qualities, and was first widely used aboard sailing ships, where it was carried in the form of either limes or lemons, and given to the sailors as part of their daily ration to both treat and prevent scurvy. Today, it is perhaps best known for its ability to help prevent or cure the common cold, although there is no scientific proof that it actually does either. It is however known to act as a powerful antioxidant and can lower the risk of suffering from both cardiovascular disease and strokes, by reducing systolic blood pressure.

Ascorbic acid and citric acid are, for all practical purposes the same thing, and ascorbic acid, in the form of citric acid, is widely used within the food industry, alongside other vitamins and minerals to fortify food. However, it is most commonly used as an additive in soft drinks, to which it brings a sour and tangy flavor.

In addition to adding citric acid to soft drinks, benzoic acid is also frequently added as a preservative, and the addition of both must be careful regulated. The reaction between ascorbic acid and benzoic acid can lead to the formation of benzene, which is far from desirable. Guidelines to prevent, or to minimize, the production of benzene have been issued by the International Council of Beverages Associations.

Ascorbic acid produces very few side effects, but care needs to be taken if you have high levels of iron in your system, as vitamin C assists iron absorption and can lead to iron poisoning. It has also been suggested that ascorbic acid can cause kidney stones and that it can suppress the important production of progesterone during pregnancy. In both cases there is little evidence to support these assertions.