Vitamin

A Vitamin is an organic molecule required by a living organism in minute amounts for normal health. An organism deprived of all sources of a particular vitamin will eventually suffer from disease symptoms specific to the missing vitamin.

Pseudo-vitamins

• Vitamin F was the designation originally given to essential fatty acids that the body cannot manufacture. They were "de-vitaminized" because they are fatty acids. Fatty acids are a major component of fats which, like water, are needed by the body in large quantities and thus do not fit the definition of vitamins which are needed only in trace amounts.
• Although there is no Vitamin S, the suggestion has been made that salicylic acid may qualify for the criteria needed to be defined as a vitamin, and that in this case the designation "Vitamin S" could be used to describe it.
• Herbalists and naturopaths have named various herbs and chemicals "vitamins", even though they are not, including Vitamin T and Vitamin U.
• Some authorities say that Ubiquinone, also called Coenzyme Q₁₀, is a vitamin. Ubiquinone is manufactured in small amounts by the body, like Vitamin D.
• Pangamic acid and the related substance dimethylglycine are sometimes referred to as Vitamin B₁₅.
• Laetrile is sometimes referred to as Vitamin B₁₇. Both pangamic acid and laetrile were first proposed as vitamins by Ernst T. Krebs; neither are recognized by the medical community as vitamins.
• Flavonoids are sometimes called Vitamin P.
• A few substances were once thought to be B-complex vitamins and are referred to as B-vitamins in older literature, including B₄ (Adenine) and B₈, but are no longer recognized as such.