Sugar Alcohols

[Desertthorn]

Cleo wrote a great article about sugar alcohols. Check it out
Low Carb Examiner: What you need to know about sugar alcohols: Not so sweet

[myabigail]

What is a laxative threshold? I've tried googling this, but I just get research papers. I'm looking for a layman's definition.

Thanks!

[Georgiana]

Originally Posted by myabigail

What is a laxative threshold? I've tried googling this, but I just get research papers. I'm looking for a layman's definition.

That's the average amount of a certain sugar alcohol a person has to consume before being "punished" in the bathroom.

[not2late]

Here's something I copied out of a nutrition book a couple of weeks ago. It's been posted on ADBB too.


Sugar Alcohols

Sugar alcohols are used as anti-reduced-cariogenic substitutes for sugars, as reduced calorie substitutes for starch or sugar, and as bulking agents when starch or sugar is removed from foods. Sugar alcohols are naturally present in fruits and vegetables. For commercial food ingredient purposes, they are generally prepared by the catalytic hydrogenation of the parent sugars.

The digestion, absorption, and metabolism of the sugar alcohols differ among the alcohols and are generally less complete than that of the parent sugars. The portion of the ingested sugar alcohols that reaches the colon undergoes anaerobic fermentation by the colonic microflora to the colon generates some usable energy but generally less than would be obtained by the parent sugar. The production of short chain fatty acids and lactic acid also lowers the pH of colonic material and may change the species distribution of colonic microorganisms. The reduced and anticariogenic properties of sugar alcohols, as compared with the caloric sweeteners, is related to their resistance to fermentaion by the oral microflora and production of rediced quantities of plaque.

Mannitol

Approximately 25% of ingested D-mannitol is absorbed via passive diffusion. Once absorbed, it is oxidize by mannitol dehydrogenase or L-iditol 2-dehydrogenase to fructose and undergoes normal fructose metabolism. The net energy value of mannitol may be low as 1.5 kcal/g.

Sorbitol

Approximately 50% of ingested sorbitol is absorbed through passive diffusion in the small intestine and up to 85% of this is metabolized. Sorbitol is absorbed more slowly than glucose. When consumed in large quantities, a laxative effect may be observed. Approximately 50% of ingested sorbitol reaches the colon, where it is rapidly fermented to short chain fatty acids, hydrogen, and methane. Estimates of the caloric value of sorbitol range from 2.0 to 3.9 kcal/g.

Xylitol

The absorption of xylitol occurs by simple diffusion and ranges from 13% to 95%. The unabsorbed xylitol is metabolized in the liver. The metabolizable energy from xylitol is approximately 2.5 to 2.9 kcal.g.

Erythritol

Erythritol has a unique metabolic fate in animals, presumably because of its low molecular weight. The sugar alcohol is almost completely absorbed in the small intestine and quantatively excreted unchanged in the urine. The result is a bulking agent with no caloric value.

Isomalt

Isomalt is an equimolar mixture of alpha-D-glycopyranosyl-1-6-d-aoebitol and alpha-D-glucopryanosylk-1,5-mannitol. Although both components are slowly hydrolyzed by various glucan 1,4-alpha-glucosidases, including jejunal mucosal enzymes, most of the energy derived from them is the result of fermentation in the colon. The energy value is approximately 3 kcal/g.

Lactitol

Lactitol is rapidly hydrolyzed to D-galactose and D-sorbitol by microbial enzymes; however, hydrolysis in the gastrointestinal tract is slow. Lactitol undergoes little or no absorption in the stomach or small intestine. Lactitol in the colon is readily fermented. Lactitol is estimated to provide approximately 2 kcal/g.

Maltitol

In the stomach, maltitol is hydrolyzed to glucose and sorbitol, both of which are readily absorbed. A substantial portion of maltitol reaches the large intestine and is fermented to short chain fatty acides. The net energy value for maltitol is approximately 3 kcal/g.

----Pediatric Nutrition Handbook 6 th Edition published by the American Academy of Pediatrics. pp 508-510. Referenced material: Finley, JW, Leveille GA. Macronutrient substitutes. In: Zeigler EE, Filer LJ Jr. eds. Present Knowledge in Nutrition. 7th ed. Washington DC: International Life Sciences Institute Press. 1996:581-595 and Henken J. Sugar Substitutes: Americans opt for sweetness and lite. FDA Consum. 1999: 33(6):12-16

[shelly808]

Thanks for the replies. Not2late, sorry but I do not understand that! Do you? If so, what does in mean in lay terms? Thank you!