Water-Soluble Vitamins

Vitamins are organized into fat-soluble and water-soluble categories. The fat-soluble vitamins require a fat-based environment in which to function, and the water-soluble vitamins require a water-based environment. To one degree or another, we have the capacity to store all vitamins. That is to say, if we ate a meal 2 days ago that contained a large amount of vitamin C but ingested no vitamin C in the foods we consumed yesterday, we wouldn't expect to suffer from symptoms of vitamin C deficiency today. Cells that require vitamin C are able to store more than they need, although there are no clear storage depots where large amounts of the vitamin can be stored. Fat-soluble vitamins, however, do have a large storage capacity. This difference in storage capacity is responsible for the commonly repeated recommendation that water-soluble vitamins should be consumed every day because they are not stored. It has also led to the myth that any excess in water-soluble vitamin intake is without problems because the excess is excreted in the urine. Although it is true that excess intake of fat-soluble vitamins, especially vitamins D and A, can produce severe toxicity, taking excess water-soluble vitamins may also lead to difficulties. A prime example of this is peripheral neuropathy (loss of feeling in the fingers), a neurological problem caused by excess intake of vitamin B₆ (500 milligrams per day over time is enough to create permanent damage). Another problem is that humans are adaptable to intake. Therefore, the more you take, the more you may need to get the same biological effect. A discussion of individual water-soluble vitamins follows.

Vitamin B₁

Vitamin B₂

Niacin

Vitamin B₁₂

Folic Acid

Biotin

Pantothenic Acid

Vitamin C