Vitamin amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. The thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B (thiamine), vitamin B (riboflavin), vitamin B (niacin), vitamin B (pantothenic acid), vitamin B (pyridoxine), vitamin B (biotin), vitamin B (folic acid or folate), vitamin B (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones). Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue
Vitamin K2 activation of coagulation factors is satisfied, but there does not seem to be enough vitamin K for the carboxylation of osteocalcin in bone and MGP in the vascular system. There is no known toxicity associated with high doses of menaquinones (vitamin K). Unlike the other fat-soluble vitamins, vitamin K is not stored in any significant quantity in the liver; therefore the toxic level is not a described problem. All data available demonstrate that vitamin K has no adverse effects in healthy subjects. The recommendations for the daily intake of vitamin K, as issued recently by the US Institute of Medicine,