Title: Alternative Sweeteners

350 Olinger and Pepper
increased fat content, although carbohydrate-modified, are not recommended.
The addition of starch, on the other hand, increases the glycemic index of the
food and eliminates the glycemic and caloric advantage that one hoped to achieve
by using an intense sweetener. To avoid these problems, bulk sugar substitutes
like fructose, sorbitol, and xylitol may be used as an appropriate alternative.
These sweeteners produce only a slight increase in blood glucose concentration
and require only small amounts of insulin for their metabolism in both healthy
and diabetic individuals.
The effects of xylitol on blood glucose and insulin levels and its general
suitability for inclusion in foods for diabetic patients have been examined in
several acute and subchronic studies with healthy and diabetic volunteers. When
xylitol is given orally, no increase in blood glucose levels is observed even in
diabetic patients (96,177–179). Similarly, plasma insulin concentrations do not
rise at all (177) or only moderately (96,180) after oral xylitol application in normal
and diabetic subjects. These observations indicate that the conversion of
xylitol to glucose—which, in principle, is possible—is apparently too slow to
raise the blood glucose concentration to a significant extent.
In a recent study involving eight healthy nonobese men, it was observed
that ingestion of xylitol caused significantly lower increases in plasma glucose
and insulin concentrations compared with the ingestion of glucose. The glycemic
index of xylitol was determined to be 7 (181).
It has been suspected that the obvious advantage of xylitol in terms of blood
glucose and insulin requirement may disappear when it is incorporated into a
meal. Therefore, a study was conducted in which 30 g xylitol or sucrose was
substituted for an equal amount of starch in a meal of a diabetic diet regimen.
The results of this investigation demonstrate that the insulin requirement after
sucrose is significantly higher than after starch or xylitol (182).
In an early subchronic study, the application of 45–60 g/day of xylitol had
no adverse effects on the metabolic condition of 20 diabetic patients (175). These
results were confirmed in a subsequent study in which the effect of 30 g xylitol/
day on the carbohydrate and lipid metabolism of 12 well-controlled diabetic patients
(type II) was examined for a duration of 2–6 weeks (183). The urinary
glucose excretion disappeared with the xylitol diet at least in some of the participating
patients. The good tolerance of xylitol was also established in a study with
18 diabetic children (type I) who received 30 g/day of xylitol for 4 weeks (184).
Even at a dose of 70 g/day administered over a period of 6 weeks, xylitol
was well tolerated by type I and type II diabetic individuals and by healthy nondiabetic
controls. Contrary to expectations, however, no significant differences
were noted in plasma glycosylated Hb, in fasting or postprandial glucose, and
in total urinary glucose (185). In conclusion, these investigations demonstrate
that xylitol can safely be incorporated as a sweetening agent in the diabetic diet
without any negative effects on their metabolic condition.