Chemical and Functional Properties of Food Saccharides

20.5.4 ARTERIOSCLEROSIS
There is no clear evidence that a high-carbohydrate diet leads directly to coronary
heart disease; nevertheless, the progression from overeating, through obesity and
diabetes mellitus, to coronary heart disease, is well known.
20.5.5 EFFECTS OF CARBOHYDRATE MALNUTRITION
Carbohydrate deficiency caused by fasting, improperly balanced diet, or diabetes
mellitus leads to ketosis: the consequence of unequal rates of β-oxidation and
oxidation of acetyl CoA in the tricarboxylic acid cycle. Except in the case of diabetes
mellitus, carbohydrate content in a diet that satisfies daily allowances maintains the
rates of both processes and prevents ketosis.
20.6 FIBER
© 2004 by CRC Press LLC
20.6.1 NONDIGESTIBLE SACCHARIDES AS ENERGY SOURCES FOR
COLONIC BACTERIA
Prebiotics are defined as nondigestible substances, the dietary fiber, maintaining
biological activity within the human organism by selective stimulation of growth or
bioactivity of beneficial microorganisms either naturally present or therapeutically
introduced to the intestine. They are nondigestible saccharides such as resistant
starch; nonstarchy polysaccharides such as pectins, guar gum, or oat gum; oligosaccharides;
sugar alcohols; and endogenic carbohydrates such as mucin and chondroitin
sulfate. In the intestine, prebiotics undergo fermentation by microflora. Currently,
particular attention is paid to saccharides belonging to the inulin group:
GlcpFruf [α-D-glucopyranosyl-(β-D-fructofuranosyl)n-1-D-fructofuranose]; Frup-
Fruf [β-D-fructopyranosyl-(β-D-fructofuranosyl)n-1-D-fructofuranose] where n =
10 to 60; fructooligosaccharides, FOS (apart from oligofructose with n = 2 to 9,
and, eventually, with D-xylose, D-galactose, D-glucose, and mannose residues); and
nondigestible oligosaccharides, NDO. Oligofructoses are present in wheat, onion,
garlic, artichoke tubers, endive, leek, asparagus, topinambur, and bananas. Mother's
milk contains relatively high levels, 3 to 6 g/l, of oligosaccharides. FOS and NDO
are selectively digested by bifidobacteria and stimulate growth of their colonies.
Therefore, in the gastric tracts of infants fed with the mother’s milk, the population
of bifidobacteria is ten times higher than in infants fed with formulae.
Intake of prebiotics promotes the growth of probiotic bacteria. It results in
inhibition of the growth of pathogenic bacteria, bacterial digestion of nutrients,
particularly proteins, and in reduction of their allergogenicity. Probiotics also synthesize
vitamins of the B-group and K as well as cytoprotective short-chain fatty
acids and polyamines such as putrescine, spermine, and spermidine. Probiotics also
metabolize some drugs. Probiotics reduce symptoms of lactase deficiency. Moreover,
probiotics degrade fiber, which osmotically increases the volume of stool and
improves action of the colon. 10