Irritable Bowel Syndrome Message Boards | Re: Carbohydrates

PMartin, I find these discussions interesting. They encourage me to review basic biochemistry and physiology. Frequently I gain new insights when I review the basics

There are different kinds of complex carbohydrates. Oligosaccharides are a particular kind of complex carbohydrate - a non-starch polysaccharide. As usual in biochemistry the same thing can have different names. Let me explain a bit more.

Carbohydrates are divided into four chemical groupings: monosaccharide, disaccharide, polysaccharide and oligosaccharide.

Here is the confusing bit. Polysaccharides consist of a number of monosaccharides linked together. Oligosaccharide are particular type of polysaccharide. They are non-starch polysaccharides consisting of 3 to 10 monosaccharides linked together.

For dietary purpose carbohydrates are simple (monosaccharide & disaccharide) or complex (oligosaccharide and polysaccharide).

Starches are complex polysaccharide carbohydrates found in potato, rice, wheat, and maize. Our body have the necessary enzymes such as salivary amylase and pancreatic alpha-amylase to break starches in simple sugars.

Dietary fiber consists of non-starch polysaccharides such as cellulose, dextrins, inulin, lignin, waxes, chitins, pectins, beta-glucans and oligosaccharides. Our bodies don't have the necessary enzymes to breakdown many of non-starch polysaccharides such as oligosaccharides into simple sugars. In particular, humans lack the intestinal enzyme alpha-galactosidase. This enzyme found in Beano from the mold Aspergillus niger diminish intestinal gas production by enhancing the breakdown of oligosaccharides before they reach the lower intestine where they would be fermented in the colon producing gas.

Complex carbohydrate intolerance (CCI) (see conclusions section in reference below) is "caused by a deficiency in enzymes to break down oligosaccharides, the difficult to digest sugar units in complex carbohydrates" As explained previously this occurs due to the absence of enzymes in the small intestine necessary for the digestion of non-starch polysaccharides high in oligosaccharide content.

Carbohydrate intolerance is a broader intolerance than CCI which includes difficulty digesting simple and complex carbohydrates such as lactose, fructose, sorbitol, starches and fibers.

The FODMAP restriction diet restricts simple and complex carbohydrates in the form of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols i.e. short chained carbohydrates that are not digested in the stomach or small intestine but reach the colon where they are fermented producing gases and byproducts.

CCI can be manage using the enzyme in Beano, lactose intolerance by taking the enzyme lactase and most of the other carbohydrate intolerances such as fructose and sorbitol malabsorption are managed by avoidance or reduced consumption.

I hope this connects a few more dots

Reference
Levine, B., & Weisman, S. (2004). Enzyme replacement as an effective treatment for the common symptoms of complex carbohydrate intolerance. Nutr Clin Care, 7(2)

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