Title: Alternative Sweeteners

260 Eberhardt
occurring colonic bacteria. Evidence of colonic fermentation has been shown
using the hydrogen breath test (7). The absorbed glucose and sorbitol are taken
up into the bloodstream. Sorbitol is converted to fructose, which is then used
through the glycolytic pathway. A review of the metabolism of sorbitol can be
found in Chapter 18.
A. Cariogenicity
It is widely accepted that prolonged exposure of the teeth to acid produces dental
caries. Sugars and starches are fermented by oral bacteria, producing organic
acids that can solubilize tooth enamel and result in decay. Because of obvious
ethical restrictions in conducting most tests of cariogenicity in human subjects,
screening for proper conditions for cariogenic potential is conducted.
‘‘Cariogenic potential’’ was defined at the Scientific Consensus Conference
on Methods for the Assessment of the Cariogenic Potential of Foods as, ‘‘the
ability of a food to foster caries in humans under conditions conducive to caries
formation’’ (8). This group also reached an agreement on a line of testing that
could be used to establish that a food had either no cariogenic potential or low
cariogenic potential. Consensus is that ‘‘foods assessed by two recommended
plaque acidity test methodologies that result in pH profiles statistically equivalent
to those generated by sorbitol would be deemed as possessing no cariogenic potential’’
(8). Demineralization of tooth enamel definitely occurs below a pH of
5.5; between 5.5 and 5.7 is a transition range, where some demineralization may
begin.
The FDA has authorized the use of the ‘‘does not promote tooth decay’’
health claim for sugar-free food products sweetened with polyols (9). The regulation
provides that ‘‘when fermentable carbohydrates are present in the sugar alcohol–containing
food, the food shall not lower plaque pH below 5.7 by bacterial
fermentation either during consumption or up to 30 minutes after consumption,
as measured by the indwelling plaque test found in ‘Identification of Low Caries
Risk Dietary Components,’ T.N. Imfeld, Volume 11, Monographs in Oral Science
(1983)’’ (10).
The relative acidogenicity of test products may be predicted on the basis
of the component makeup of the compounds. Theoretically, HSH with higher
hydrogenated saccharides (molecules DP4 and larger) would be more likely to
result in the release of free glucose after hydrolysis, which is readily fermentable
by oral bacteria (11). Because HSH products differ in their saccharide profile,
studies have been conducted to examine the cariogenicity of each HSH. Although
HSH with higher concentrations of higher DP saccharides show a greater drop
in pH than those with lower DP fractions, each has been shown to remain above
the 5.7 ‘‘safe for teeth’’ value (3,11).