FERMENTABLE OLIGOSACCHARIDES, DISACCHARIDES, MONOSACCHARIDES AND POLYOLS AND THEIR ROLE IN FOOD DIGESTION

Oligosaccharides containing fructose (fructans, inulin), galactose (galactans, stachyose, raffinose), disaccharides enclosing galactose (lactose), monosaccharides and mixtures of monosaccharides encompassing fructose (fruit sugar, honey) and saccharide polyols (mannitol, malbitol, sorbitol), are considered as safe to be consumed and beneficial to health. Gradually, however, their presence in the human diet reaches amounts that are indigestible by the small intestine, causing an osmotic load on the intestinal lumen. Subsequently, they pass into the large intestine, where they are fermented by intestinal bacteria to undesirable products such as gaseous carbon dioxide, hydrogen, methane, sulfane, and short chain fatty acids. Indigestible fermentable oligosaccharides, disaccharides, monosaccharides, and polyols may cause undesirable symptoms such as an increased flatulence, bloating, abdominal pain, alterations to the intestinal physiology, cessation of peristalsis, or diarrhea, which are manifested by a wide array of diseases of the gastrointestinal tract, such as the irritable bowel syndrome or small intestinal bacterial overgrowth. Fruits, vegetables, dairy products, legumes, some cereals, as well as honey or various sweeteners are among the most common food sources of these carbohydrates.