Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
20.5.1.2 Fructose Intolerance
Fructose is metabolized without insulin. Therefore, it is a safe sweetener and energy
source for diabetics. Fructose intolerance, however, also occurs. It is an inherited
metabolic disorder resulting from the lack of fructose-1-phosphate aldolase. When
the disorder is diagnosed, a fructose-free diet is recommended. 7
20.5.1.3 Oligosaccharide Intolerance
Low activity of disaccharidases in the gut causes suppressed hydrolysis of disaccharides
in its anterior part. Nonhydrolyzed disaccharides serve as nutrients for
bacteria in the posterior part of the gut. Excessive fermentation in the large intestine
produces abdominal bloating, flatulence, and borborygmi and is caused by gaseous
products of bacterial fermentation. Unabsorbed disaccharides increase the osmotic
tension of intestinal content, causing a water shift to the lumen of the gut. Osmotic
tension also accelerates transit time, producing diarrhea and other abdominal complaints.
Primary and secondary lactose intolerances are serious medical problems. In
primary hypolactasia, children are born with normal lactase activity, which then
starts declining at the age of three. Approximately 70% of adults in non-White
populations are susceptible to lactase deficiency; among the Whites, however, the
percentage drops to below 40%. Secondary hypolactasia is usually a transient phenomenon.
It occurs as a consequence of damage to the small intestine mucosa. With
restoration of the mucosa, lactase activity improves. 8 Sucrose intolerance has been
reported in Eskimos.
20.5.2 OBESITY
With the exception of certain single-gene disorders, the etiology of obesity depends
on a number of factors or causes and results from overloading with energy. Storage
of glucose as glycogen is limited. Usually, in adult persons, reserves of glycogen
do not exceed 100 g in the liver and 150 to 400 g in the muscles; as a consequence,
excess of consumed sugars is converted into triglycerides. Accumulation of lipids
in the human body seems to be unlimited. A number of obese people carry over 100
kg of fat in their body. Eating meals with unrestricted levels of carbohydrates,
especially simple carbohydrates, produces simple obesity. Epidemiological research
points to NIDDM occurring more frequently in obese people than in lean people. 9
20.5.3 CARIES
Epidemiological data show that the risk of caries is lower in countries where the
annual sugar consumption is below 10 kg per person. Particularly, sucrose in food
with texture permitting adhesion to the teeth produces high risk of dental caries.
Therefore, some other carbohydrates and carbohydrate-derived sweeteners, such as
polyols (sorbitol, maltitol), which are not metabolized by oral microorganisms, are
more desirable.