Vitamins are a general description for a class of unrelated organic compounds required in trace quantities by a living organism for the proper regulation of reproduction, growth, health and metabolism. They do not include dietary minerals or essential fatty and amino acids and are not a direct source of calories. Humans require around 13 essential vitamins. Except for vitamins D and K, which can be synthesized by the body, they must be obtained through the diet or from man-made supplements. Vitamins are classified as either fat-soluble (A, D, E, K) or water-soluble (B, C). They can be obtained from fruits, vegetables, grains and cereals. Vitamin D is present in milk or sometimes added to milk as a supplement and can also be synthesized by cells in the skin using ultraviolet light from the sun. The water-soluble vitamins are readily lost during cooking. Vitamin deficiencies are the cause of diseases like scurvy (C deficiency), anemia (A deficiency), rickets (B deficiency) and various birth defects. Consuming more than the minimum daily requirement has not been shown to provide any significant health advantage and may be harmful in the case of vitamins like A that can accumulate in fatty tissue in the liver.
- ascorbic acid (Vitamin C)
Ascorbic acid (Vitamin C) is an essential nutrient found in fruit juices and used as a vitamin supplement in food. It is most often measured using colorimetry and HPLC.
Niacin (nicotinic acid)is an essential nutrient found in meats and cereals and used as a dietary supplement in foods. It is most often measured colorimetrically and by HPLC.
Riboflavin (vitamin B2)is a vitamin found naturally in foods and added to enriched flours. It is most often measured using HPLC.
- thiamine (Vitamin B1)
Thiamin (Vitamin B1), a coenzyme essential for carbohydrate metabolism, is found in all plants and also produced synthetically. It is most often measured usng fluoresence and HPLC techniques.
- vitamin A
Vitamin A, an essential nutrient required for growth and vision is obtained commercially from fish oil. It is most often measured using spectrophotometry and HPLC.
- vitamin D2
Vitamin D2 is an essential nutrient that maintains plasma calcium and phosphate levels. It is most often measured using colorimetry and HPLC.
- vitamin D3
Vitamin D3 is an essential nutrient that facilitates caclium and phosphate absorption. It is most often measured using colorimetry and HPLC.
- vitamin E
Vitamin E (alpha-tocopherol) is an antioxidant found in vegetable oils. It is most often measured using GC/FID and HPLC.
- vitamin K
Vitamin K, synthetically derived from 2-methyl-1,4-naphthoquinone and phytol is used to treat blood coagulation disorders. It is most often measured using GC/FID and HPLC.