Biotin Deficiency
Various microorganisms, including bacteria, yeasts, and molds, require biotin; it is a vitamin for these organisms. It is also a required dietary vitamin for man, monkey, dog, rat, rabbit, turkeys, chickens, and some other species. It was early postulated that egg white in the intestinal tract combined with and held in an unabsorbable form the protective factor of the diet. This was based on various observations including the fact that feces from rats showing egg white injury were protective only after heating. Other workers concluded somewhat the same thing in studies on chicks, and later they showed that a constituent of rave-egg white rendered biotin unavailable for yeast growth. Wooiley and Langsworth prepared an amorphous fraction from egg white that was 15,000 times ,as active as egg white.
Avidin occurs combined with nucleic acid and carbohydrate. The free protein is highly basic and has a molecular weight of 60,000 to 70,000. One molecule combines with two molecules of biotin. In animals biotin deficiency cannot always be produced by maintaining them on diets deficient in this factor, presumably on account of bacterial synthesis in the intestinal tract.
Many experiments have indicated a greater excretion than dietary intake of biotin. This has also been demonstrated in human beings. Besides feeding egg white diets, the symptoms have been produced by incorporating a sulfonamide drug in the diet (to minimize intestinal bacterial growth) or by supplementing the diet with one of the various biotin antagonists. Hamsters fed a diet containing 40 per cent egg white supplemented with sulfaguanidine showed extreme deficiency in six weeks, Weight gain was far below normal, and the animals were 'table and nervous. They showed jerky movements and dragged their hind legs. The eyes "re sealed shut with incrustations, and the mouth and nose were swollen. They became ::.early hairless.
Symptoms disappeared rapidly following daily injections of 4 Ilg of biotin. Boas fed rats on zets high in raw egg white and observed a dermatitis, loss of hair, and loss of muscular control. Secific studies on nervous tissue and muscle of deficient animals were reported by Sullivan d others. Experimental studies on human biotin deficiency have been reported . .sydenstricker and associates fed egg white-containing diets to adult volunteers. After three -- four weeks a transient dermatitis was seen, and shortly thereafter lassitude, anorexia, uscle pains, and hyperesthesia were observed.
The administration of 150 to 300 mg daily of a biotin concentrate relieved these symptoms a few days. During the course of the experiment the urinary excretion of biotin decreased md rose abruptly upon therapy with the vitamin. Other investigators have not confirmed i.e production of human biotin deficiency symptoms by feeding egg white or avidin ncentrates. Follis has reviewed the symptomatology of deficiency in animals and in man.
