Vitamins are a group of substances that are needed for normal cell function, growth, and development. There are 13 essential vitamins:
Vitamin A (retinol, retinal, 4 carotenoids)
Vitamin C (ascorbic acid)
Vitamin D (D3 - Cholecalciferol, D2 - Ergocalciferol)
Vitamin E (tocopherols, tocotrienols)
Vitamin K (phylloquinone, menaquinones)
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12 (cyanocobalamin)
Fat-soluble vitamins are stored in the body's fatty tissue: vitamins A, D, E, K.
Water-soluble vitamins - the body must use almost all water-soluble vitamins right away - vitamins B1, B2, B3, B5, B6, B7, B9 and C. Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years.
Carotenoids are a class of more than 750 pigments synthesized by plants, algae, and photosynthetic bacteria. These richly colored molecules are the sources of the yellow, orange, and red colors of many plants. Fruit and vegetables provide most of the 40 to 50 carotenoid phytonutrients found in the human diet.
The most common carotenoids in North American diets are α-carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene.
Provitamin A carotenoids - α-carotene, β-carotene, and β-cryptoxanthin - can be converted by the body to retinol (vitamin A), but not lutein, zeaxanthin, and lycopene.
Dietary lutein and zeaxanthin help maintain optimal visual function - they absorb damaging blue light that enters the eye.
The results of observational studies suggest that diets high in carotenoid-rich fruit and vegetables are associated with reduced risks of cardiovascular disease and some cancers. But high-dose β-carotene supplements did not.