Discovered due to it’s importance in preventing scurvy, the plague of sailors in the Age of Exploration, vitamin C is an essential element of a healthy diet. It acts as a cofactor in the production of a multitude of biologically important molecules, from collagen to dopamine.
Nowadays, scurvy isn’t as big an issue and vitamin C is valued for its efficiency and potency as an antioxidant. This water-soluble vitamin is actually such a good antioxidant that it recycles other antioxidants after these compounds are themselves oxidized.
Now, something this important sounds like something we should be able to manufacture ourselves, yes? For almost all animals, including most mammals, vitamin C can be manufactured by the organism itself. However, in some primates, including all humans, vitamin C must be acquired through diet.
In studies, both supplemental and dietary vitamin C have been shown to lower cardiovascular disease related deaths. Additionally, it can lower both LDL cholesterol (without effecting HDL) and blood triglyceride levels. That is nothing to sneeze at, since the Centers for Disease Control cites heart disease as the leading cause of death among American women, causing 1 in 4 women’s deaths.
What about vitamin C and the common cold? Studies have shown that in an otherwise healthy person, the common cold may be shorter in duration, but not in severity. Furthermore, taking vitamin C isn’t going to prevent getting the common cold (unless you are a bit deficient, in which case it will help).
Peppers, broccoli, kale, cabbage, peas, guava, and black currents are all better sources of vitamin C than citrus fruits. You can check out the list here.
De Tullio, M. C. (2010) The Mystery of Vitamin C. Nature Education 3(9):48
Higdon, Jane. (2006) Vitamin C. Linus Pauling Institute. Updated November 2013 by Alexander J. Michels, Linus Pauling Institute Oregon State University.
Women and Heart Disease Fact Sheet from the Centers for Disease Control
Vitamin C and Immune Function. Abstract. Med Monatsschr Pharm. 2009 Feb;32(2):49-54; quiz 55-6.