Nutritional and Health Aspects of Sweeteners - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 348

and, after saccharin consumption, to increase food intake. However, most investigators have found
that aspartame consumption is associated with decreased or unchanged ratings of hunger. Even
if aspartame consumption increases ratings of hunger in some situations, it apparently has little
impact on the controls of food intake and body weight. Furthermore, aspartame does not seem to
increase food intake; indeed, both short- and long-term studies have demonstrated that the con-
sumption of aspartame-sweetened foods or drinks is associated with either no change or a reduced
food intake. In addition, preliminary clinical trials suggest that aspartame may be a useful aid in
a complete diet-and-exercise program or in weight maintenance. Finally, it should be mentioned
that intense sweeteners have never been found to cause weight gain in humans (Rolls 1991). Those
indings suggest that the calorie contained in natural sweeteners may trigger a response to keep the
overall energy consumption constant.
Rodent models helped elucidate how artiicial sweeteners contribute to energy balance. Rats
conditioned with saccharin supplement had signiicantly increased total energy intake and gained
more weight with increased body adiposity compared to controls conditioned with glucose accord-
ing to Swithers and Davidson (2008).
Recent epidemiological evidence by Swithers et al. (2010) pointed to a link between a variety of
negative health outcomes (e.g., metabolic syndrome, type II diabetes, and cardiovascular disease)
and the consumption of both calorically sweetened beverages and beverages sweetened with high-
intensity, noncaloric sweeteners. Research on the possibility that nonnutritive sweeteners promote
food intake, body weight gain, and metabolic disorders has been hindered by the lack of a physio-
logically relevant model that describes the mechanistic basis for these outcomes. The researchers
suggested that, based on Pavlovian conditioning principles, the consumption of nonnutritive sweet-
eners could result in sweet tastes no longer serving as consistent predictors of nutritive postinges-
tive consequences. This dissociation between the sweet taste cues and the caloric consequences
could lead to a decrease in the ability of sweet tastes to evoke physiological responses that serve to
regulate energy balance. Using a rodent model, they have found that the intake of foods or luids
containing nonnutritive sweeteners was accompanied by increased food intake, body weight gain,
accumulation of body fat, and weaker caloric compensation compared to the consumption of foods
and luids containing glucose. They also provided evidence consistent with the hypothesis that these
effects of consuming saccharin may be associated with a decrement in the ability of sweet taste to
evoke thermic responses and perhaps other physiological, cephalic-phase relexes that are thought
to help maintain energy balance (Swithers et al. 2010).
Moreover, saccharin-conditioned rats also failed to curb their chow intake following a sweet
premeal. When a lavor was arbitrarily associated with high or low caloric content, rats ate more
chow following a premeal, with the lavor predictive of low caloric content (Pierce et al. 2007).
These studies pose a hypothesis: inconsistent coupling between sweet taste and caloric content can
lead to compensatory overeating and positive energy balance (Yang 2010).
Using both cross-sectional and longitudinal data from the Framingham Heart Study, Dhingra et
al. (2007) reported positive relationships between the consumption of diet soda and the prevalence
of the metabolic syndrome that were larger than that obtained with the consumption of regular soda.
Similar results have also been reported as part of independent studies of Lutsey et al. (2008) and
Nettleton et al. (2009). Furthermore, Fowler et al. (2008) reported that, for humans who were nor-
mal weight or nonobese (BMI < 30 kg/m 2 ) at baseline, the intake of >21 nonnutritively sweetened
beverages per week (diet sodas and artiicially sweetened coffee and tea) was associated with about
double the risk of obesity compared to nonusers at follow-up 7 to 8 years later.
11.5.6 Can Consumption of high-Intensity Sweeteners Disrupt energy Balance?
Roy et al. (2007) have suggested that rats exposed to saccharin showed an increase in body
weight and caloric intake compared to rats exposed to the caloric sweetener glucose. The authors