Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
20.4.2 SACCHARIDE DAILY ALLOWANCES
Saccharides make up 25 to 52% of energy requirements of newborns whether fed
naturally or by formula. Mother's milk includes lactose, and formula contains glucose,
lactose, or maltodextrins, or all three. These components are the most suitable
for infants because of the low activity of their amylolytic enzymes. A residual activity
of amylase can be found in pancreatic juice in the third month of an infant's, life
which slowly increases in the following months. 5 In the adult diet, carbohydrates
should make up over 50 to 65% of the energy requirements, which corresponds to
320 to 460 g of saccharides daily. In humans, a diet consisting mainly of polysaccharides
can provide up to 70% of energy needs. The main rule of dietetics is to
limit intake of mono- and disaccharides and to increase the level of complex carbohydrates
in the diet. A daily fiber intake of 27 to 40 g is recommended. In Europe,
grain products are the most common source of carbohydrates. A considerable amount
of carbohydrates is ingested with sweets, cakes, and soft drinks. Carbohydrates from
fiber-rich fruits and vegetables constitute a minor part of ingested saccharides.
Honey, candied fruits, and products of processed potato starch are the foods richest
in saccharides (Table 20.1).
20.5 CARBOHYDRATES AND HEALTH
20.5.1 CARBOHYDRATE INTOLERANCE
Some pathogenetic and symptomatic diseases cause carbohydrate intolerance. Glucose
intolerance resulting from the shortage of insulin is the most common. Intolerance
to disaccharides is activated by the absence of specific enzymes in the gut.
20.5.1.1 Glucose Intolerance and Diabetes
Glucose intolerance relates to diabetes and impaired glucose tolerance. The latter is
a stage between normal glucose homeostasis and diabetes. Frequently, impaired
glucose tolerance is a prediabetic stage.
Diabetes can be an insulin-dependent diabetes mellitus (IDDM), insulin-independent
diabetes mellitus (NIDDM), and a few other specific types. Insulin facilitates
the transfer of glucose from blood to the cells. Shortage of insulin results in
high concentration of glucose in blood and low level of this energy-producing
material in the cells. A high glucose level in blood changes its osmolality, producing
some clinical symptoms. More important, the low level of glucose in the cells
impairs their metabolism. IDDM is caused by immunodestruction of pancreatic
islets. In NIDDM, the shortage of insulin is relatively insignificant. It results from
resistance of cells to insulin, impaired insulin secretion, and excessive glucagon
secretion. The relationship between NIDDM and diet is not clear. Some papers
demonstrate that a diet rich in simple carbohydrates and animal fat is more diabetogenic
than a diet rich in complex carbohydrates; however, several papers contradict
this point of view. 6