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 K K, and primary deficiency is rare in healthy adults. Newborn infants are at an increased risk of deficiency. Other populations with an increased prevalence of vitamin K deficiency include those who suffer from liver damage or disease (e.g. alcoholics), cystic fibrosis, or inflammatory bowel diseases, or have recently had abdominal surgeries. Secondary vitamin K deficiency can occur in people with bulimia, those on stringent diets, and those taking anticoagulants. Other drugs associated with vitamin K deficiency include salicylates, barbiturates, and cefamandole, although the mechanisms are still unknown. Vitamin K deficiency has been defined as a vitamin K-responsive hypoprothrombinemia which increase