Some clinically proven supplements reduce carbohydrate absorption except glucose and fructose - since the area under the curve = AUC of glucose after ingesting carbs other than simple sugars is reduced by the now much less prescribed antidiabetic drug Acarbose, an Alpha-glucosidase inhibitor.
Acarbose isn't taken up by the body, has the structure of a sugar, and inhibits the enzyme alpha-glucosidase by Competitive inhibition present in the small intestinal Brush border that is needed to break down oligosaccharides, trisaccharides and disaccharides (e.g. sucrose in beet and cane sugar) to simple monosaccharides so they can be absorbed into the body, this compound also inhibits the enzyme pancreatic amylase that is needed to break down starches into oligosaccharides so that they can be further broken down by alpha-glucosidase, (as shown in image)
This slows down the digestion of complex carbohydrates (not the simple sugars like glucose or fructose) and if dosed high enough will cause loss of undigested carbohydrates into the large bowel causing the notorious side effects being bloating, flatulence and diarrhea. What is lost won't be absorbed.
Alpha-glucosidases are present in many plants, one of the commercially available substances is at present not well researched Quercetin we know too little about.
