Reviewing the The Role of Anti-oxidants lesson may help with some of the terminology in this lesson.
Ascorbic acid is probably the star of all the vitamins, simply because of the huge amount of exposure it has received over the last 30 years. However, a deficiency in any nutrient existing will affect the body, and the amount of the deficiency determines the negative effects on the body.
Vitamin C uses only water to go through the body and helps the body to create certain hormones, helps the brain to function properly, helps break down the fatty acids from both food and supplement sources, and helps the body's connective tissue to be rebuilt via collagen.
In addition, it is also an antioxidant and helps vitamin E be an antioxidant as well (see that lesson). Because the immune system is so crucial to our overall health, and is continually being exposed to threats, we can be particularly thrilled about vitamin C--it is a key antioxidant to keep it clean of free radicals.
Because vitamin C is water-soluble, it is excreted via the kidneys through the urine. It is said by some that "all vitamin supplements do is make people have very expensive pee." It is my opinion that this statement is not fair. Because the body is continually trying to maintain homeostasis, there is no way to know what vitamin C needs the body has at any given moment. Perhaps the brain needs more help with its neurotransmitting. Maybe there is a need for the thyroid hormone. Maybe there is an urgent need to help the body to create the protein collagen and maintain the collagen that is already there. Eating vitamin C-rich food is easy and fairly tasty. While the best supplementation is liquid whole food, arguments can be made for consumption of vitamin C in other forms.