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"DISCOVERY" OF XYLITOL
In September, 1890, the German chemistry professor Emil Herman Fischer and his assistant, Rudolf Stahel, separated from beech chips a new compound which was named Xylit, the German word for xylitol (Fischer and Stahel, 1891). Later, in 1902, owing to his versatile chemical achievements, Dr. Fischer was awarded the Nobel Prize in chemistry.
Almost simultaneously with Fischer, the French chemist M.G. Bertrand had managed to isolate xylitol syrup by processing wheat and oat straw (Bertrand, 1891). The "discovery" of xylitol must therefore be credited to two groups of researchers.
During the next five decades, xylitol received little attention. During the 1950s, however, Dr. Oscar Touster, who worked at that time in Nashville, Tennessee, found by accident that the metabolism of xylitol in humans is associated with pentosuria.
That the history of xylitol was indeed quite "eventless" for the first 50 to 60 years after its first description in 1891 is reflected, for example, by an early statement that "these compounds [pentitols] have never been studied physiologically" (Cart and Krantz, 1945). Dr. Touster's work was to change that situation remarkably. By the mid-1950s, he and his co-workers had concluded that xylitol is formed in the human body. This discovery stemmed from investigations on L-xylulose, the characteristic urinary sugar in essential pentosuria. This is a harmless, rare, recessive genetic disorder initially found in Jews and Arabs. Dr. Touster reasoned that essential pentosuria involved the accumulation and excretion of a metabolite which is readily disposed of in normal, but not in pentosuric, individuals. Eventually, the product was isolated and characterized as xylitol (Touster and Shaw, 1962).
THE DAWN OF THE CARIOLOGIC INSIGHT
To me as a biochemist, the most intriguing chemical characteristics of the xylitol molecule are its "polyol properties". These include the ability of xylitol to form complexes with certain canons, such as Ca(II), Cu(II), and Fe(II) (Angyal et al., 1974). Another interesting feature of the xylitol molecule is its capacity to displace water molecules from the hydration layer of proteins and also from that of the above-mentioned cations (Lewin, 1974; Gekko and Satake, 1981). In 1969, xylitol was introduced to me as a possible sugar substitute. There was no clinical information on the possible effects of xylitol on dental caries, however. In...