| Vitamins
Vitamins are nutrients required for essential metabolic reactions in the body. Vitamins can act both as catalysts and participants in the chemical reaction. The body typically assembles vitamin-dependent catalysts from a variety of building blocks including amino acids, sugars, phosphates, and vitamins. Each vitamin is typically used in multiple different catalysts and therefore has multiple functions. The role of a catalyst is to participate in a chemical reaction without being altered itself. Catalysts function like knitting needles, which convert yarn to mittens without undergoing any change themselves.
Until the 1900's, vitamins could only be obtained by eating food. Each food source contains different ratios of vitamins. Therefore if the only source of vitamins is food, a change in diet from season to season, year to year, or day to day changes the doses of vitamins. Ordinary people do not sense any change in health as a consequence. This leads to the conclusion that the nervous system maintains a feeling of normalcy across a wide range of vitamin dosages.
Vitamins have only been produced as commodity chemicals and made widely available as inexpensive pills for a few decades. For the first time in human history, parents are empowered to independently control the doses of vitamins eaten by themselves and their children. Because the catalytic action of vitamins is ordinarily imperceptible except at the extremes of deficiency and overdose, the vast majority continues to depend upon food as the sole source of vitamins.
Vitamins can be classified as either water soluble, which means they dissolve easily in water, or fat soluble, which means they are absorbed through the intestinal tract with the help of lipids.
Some vitamins can also be obtained from precursors which can be obtained in the diet. Examples include vitamin A, which can be produced from beta carotene and niacin from the amino acid tryptophan.
The term vitamin does not encompass other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor is it used for the large number of other nutrients that merely promote health, but are not strictly essential.
In humans, there are thirteen vitamins, divided into two groups, the four fat-soluble vitamins (A, D, E and K) and the nine water-soluble vitamins (eight B vitamins and vitamin C).
| Vitamin Name |
Chemical Name |
Solubility |
Deficiency Disease |
Overdose |
Estimated Average Minimum Daily Requirement
(male, aged 19-30) |
| Vitamin A |
Retinol |
Fat |
Night-blindness, Keratomalacia |
7.5 mg |
620 µg |
| Vitamin B 1 |
Thiamine |
Water |
Beriberi |
n/a |
1000 µg |
| Vitamin B 2 (G) |
Riboflavin |
Water |
Ariboflavinosis |
n/a |
1100 µg |
| Vitamin B 3 (PP) |
Niacin |
Water |
Pellagra |
2500 mg |
12000 µg |
| Vitamin B 5 |
Pantothenic acid |
Water |
Paresthesia |
n/a |
10000 µg |
| Vitamin B 6 |
Pyridoxine |
Water |
n/a |
400 mg |
1100 µg |
| Vitamin B 7 (H) |
Biotin |
Water |
n/a |
n/a |
30 µg |
| Vitamin B 9 (M) |
Folic acid |
Water |
n/a |
1 mg |
320 µg |
| Vitamin B 12 |
Cyanocobalamin |
Water |
Pernicious Anemia |
n/a |
2 µg |
| Vitamin C |
Ascorbic acid |
Water |
Scurvry |
n/a |
75000 µg |
| Vitamin D 1 –D 4 |
Lamisterol, Ergocalciferol, Calciferol, Dihydrotachysterol,
7-dehydrositosterol |
Fat |
Rickets |
1.25 mg |
2 µg (for all Vitamin D) |
| Vitamin Er |
Tocopherol |
Fat |
n/a |
33000 mg |
12000 µg |
| Vitramin K |
Naphthoquinone (not to be confused with Ketamine) |
Fat |
Bleeding diathesis |
n/a |
75 µg |
|