In the 1930s, scientists began to search for a missing member of the B family--this one, a vitamin that could cure acrodynia, a skin disorder in rats that appeared to resemble the human disease, pellagra. Pellagra was already known to be a deficiency disease that could be prevented or cured by adding niacin (vitamin B3) to the diet. Logically, then, niacin should work on acrodynia as well. But in 1934, Paul György (1893-) discovered that it didn't work at all. Moreover, György--a Hungarian-born physician who emigrated to the United States--had earlier learned that neither vitamin B1 (thiamine) nor vitamin B2 (riboflavin) has much effect on the rat- pellagra either. György was so convinced that a curative factor did exist, however, that he proposed the name vitamin B6 for it, if and when it was found.
And a few years later,in 1938, five separate groups of researchers— including György and several coworkers, and Richard Kuhn --finally did isolate a crystalline material from rice bran or yeast that, among other things, could both prevent and cure acrodynia. Duly named vitamin B6 (or pyridoxine). The new vitamin's structure was determined in 1939 and, in that same year, its synthesis was accomplished by S. A. Harris (1902-) and Karl Folkers, industrial chemists working for a well-known pharmaceutical company.
Although scientists originally believed B6 was a single compound, they soon discovered the new vitamin is actually a complex of closely related compounds that act as coenzymes in several types of reactions. The primary role of B6 apparently is to help promote protein metabolism (it helps convert tryptophan to niacin, for one thing). It also assists in the synthesis of hemoglobin and of two important neurotransmitters (chemical messengers), serotonin and gamma-aminobutyric acid (GABA).
Although deficiencies of B6 are rare in healthy adults, they can sometimes be seen in infants on inadequate diets. In fact, the need for B6 in humans was first definitely established back in the 1950s when several hundred infants around the country suddenly developed convulsive seizures. The cause of the seizures was traced to a canned infant formula that, through improper heat treatment, had lost most of its B6 content. A number of medications--such as oral contraceptives and anti- tuberculosis drugs--can also affect B6 status. And, because the need for B6 appears to increase in pregnancy, B6supplements are often given to expecting mothers. In the early 1990's, deficiencies in B6, and other vitamins, were reported in Cuba as a result of the U.S. trade embargo. Between 1989 and 1995 the daily caloric intake for the citizens of this country went down a third, and serious problems with malnutrition, low birth weights, and vitamin deficiencies occurred as a result.
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