Function and Sources. Biotinparticipates as a coenzyme in the syn-thesis of fatty acids and amino acids. Some of its best dietary sources are egg yolks, milk, poultry, fish, broccoli, spinach, and cauliflower. Biotin is also synthesized in the intestine by microorganisms, but the amount that is available for absorption is unknown.
Requirements.Biotin is measured in micrograms. The Food and Nutri-tion Board of the Institute of Medicine has established an AI of 30μg for adults (see Table 7-2).
Deficiency.Deficiency symptoms include nausea, anorexia, depression,pallor (paleness of complexion), dermatitis (inflammation of skin), and an in-crease in serum cholesterol. Toxicity from excessive intake is unknown.