Basic Description

Vitamin C may be the most familiar of all of the nutrients. Although most adults would be hard pressed to name a good food source of biotin or riboflavin, most everyone can name citrus fruits good sources of vitamin C. It is also a commonly used nutritional supplement, with many outsized claims for its clinical efficacy.

The first use of modern scientific methods to assess disease treatment was when the British navy used foods containing vitamin C (although the vitamin itself would remain undiscovered for nearly two centuries) to prevent scurvy among sailors. You could make a good case that this nutrition experiment is among the most important scientific findings in human history.
Protection against Free Radicals

Vitamin C is probably best known in the modern world as an antioxidant. This is a word that we use frequently but is surprisingly hard to understand or define. If we define free radicals as a smoldering fire creating damage to body structures, then antioxidants are best described as a fire extinguisher, able to neutralize these radicals, and dispose of them without creating any damage along the way. Dietary vitamin C has been shown to fit this description well. Some of the items possibly protected by dietary vitamin C include the lens of the eye, cholesterol in the blood stream, and DNA in your cell nucleus.

One interesting application of vitamin C as an antioxidant is its ability to reduce iron into a state that is better absorbed in the intestine.

Collagen Vitamin C is required to produce collagen, a protein that plays a critical role in the structure of our bodies. Collagen is the framework for our skin and our bones, and without it, we would quite literally fall apart.
This is exactly what we see with severe vitamin C deficiency, or scurvy. People who have this condition lose teeth, bleed easily, and lose the strength of their bones. Luckily, it doesn’t take much vitamin C to prevent this problem. As we’ve known for more than two centuries, a single lime per day should be enough. Brain Health

Vitamin C is necessary to make certain neurotransmitters. These neurotransmitters are the signals that carry thoughts, feelings, and commands around our brains.

In particular, we need vitamin C to produce serotonin, the neurotransmitter that is affected by the most commonly used medications for depression. While we are not suggesting that vitamin C from foods or from supplements would have a similar effect to drug therapies for depression, we do recommend including fresh fruits and vegetables in the diet regularly as part of an overall mood support strategy.

Relationship with Other Nutrients

Vitamin C increases the absorption of iron (especially the iron found in plant foods) and may help those at risk for iron deficiency stay out of deficit. Although some sources suggest that this should be supplemental vitamin C, the nutrient derived from food will do this, too. For those at risk of iron overload, you may need to be careful about combining foods rich in iron with those rich in vitamin C.

Antioxidants in foods tend to work together in important and synergistic ways to provide protection against free radical damage. The most well-known of these connections is that between vitamin E and vitamin C. Specifically, vitamin C helps to protect vitamin E in people, such as smokers, who have chronic overproduction of free radicals.

Storage:

Store at room temperature. Protect from heat, light and moisture. Keep away from reach of children.