8.1 Vitamins

Vitamins

The name vitamin comes from Casimir Funk, who in 1912 thought vital amines (NH₃) were responsible for preventing what we know now are vitamin deficiencies. He coined the term vitamines to describe these compounds. Eventually it was discovered that these compounds were not amines and the ‘e’ was dropped to form vitamins1.

Vitamins are classified as either fat-soluble or water-soluble. The fat-soluble vitamins are:

• Vitamin A
• Vitamin D
• Vitamin E
• Vitamin K

VitaminCommon NameB1ThiaminB2RiboflavinB3NiacinB5Pantothenic AcidB6*PyridoxineB7Biotin
The water-soluble vitamins are vitamin C and the B vitamins, which are shown in Table 8.11. Table 8.11 The B vitamins and their common names

*Normally used instead of common names

Before they even knew that vitamins existed, a scientist named E.V. McCollum recognized that a deficiency in what he called ‘fat-soluble factor A’ resulted in severe ophthalmia (inflammation of the eye) 1. In addition, a deficiency in ‘water-soluble factor B’ resulted in beriberi (a deficiency discussed more later)1.

Figure 8.11 Factor A deficiency led to ophthalmia, factor B deficiency led to beriberi

Factor A is what we now know as vitamin A. However, researchers soon realized that factor B actually consisted of two factors that they termed B₁ and B₂. Then they realized that there are multiple components in B₂, and they began identifying the wide array of B vitamins that we know today1.

You might be thinking “but the numbers on the B vitamins still do not add up.” You are right, vitamins B₄, B₈, B₁₀, and B₁₁ were discovered and then removed leaving us with the B vitamins shown in Table 8.11.

Relative to other scientific milestones, the discovery of vitamins is a fairly recent occurrence, as shown in Table 8.12.

Table 8.12 Vitamin, year proposed, isolated, structure determined, and synthesis achieved up to 19441

* Was established long before it was known to be a vitamin

A number of B vitamins serve as cofactors/coenzymes. The following table lists the cofactors/coenzymes formed from B vitamins that will be discussed in more detail in the following subsections.

Table 8.13 Cofactors/coenzymes formed from B vitamins

References & Links

1. Carpenter K. (2003) A short history of nutritional science: Part 3 (1912-1944). J Nutr 133(10): 3023-3032