Sorbitol is a sugar alcohol and is poorly digested or absorbed by the small intestine. It passes through to the colon where it produces an osmotic purge that can lead to diarrhea, dehydration and consequently malabsorption of nutrients. Undigested food means bacterial fermentation and hydrogen production, which can result in bloating, cramp and gas. Part of the hydrogen produced is absorbed and subsequently excreted through the lungs. Sorbitol is a natural laxative found in pears, apple, red grapes, prunes and other fruits.
Raffinose is a complex sugar (composed of galactose, fructose, and glucose). Poorly digested raffinose causes fermentation in the colon, gas and intestinal distress. Several foods contain the carbohydrate raffinose including beans, cabbage, Brussels sprouts, cauliflower, broccoli and others.
Fructose is characterized by the inability of the small intestine to absorb fructose efficiently. As a consequence fructose arrives in the colon were it is fermented by colonic bacteria, and gases like hydrogen, carbon dioxide and methane are produced. People with fructose intolerance can experience bloating, cramps, osmotic diarrhea and other symptoms. Fructose occurs naturally in onions, artichokes, wheat, and fruits.
Individuals with lactose intolerance are unable to digest significant amounts of lactose because of an inadequate amount of the enzyme lactase. Without adequate amounts of this enzyme, much of any lactose consumed goes undigested into the large intestine. In the colon it becomes fermented by bacteria, resulting in gas, diarrhea and abdominal cramps. The problem is that these halitosis bacteria can break down the lactose proteins (full of sulfur) to cause smell and bad tastes. Lactose is the predominant sugar in milk and other dairy products.
Sucrose is a complex sugar (composed of glucose and fructose). In sucrose intolerance, sucrase, an enzyme necessary for proper metabiolization of sucrose, is not made in the small intestine. As consequence the body produces excessive gas and diarrhea. Also malabsoption.
Gluten (Celiac Disease)
People who have gluten or celiac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley. When people with celiac disease eat food containing gluten, their immune system responds by damaging or destroying the villi (tiny, fingerlike protrusions) on the lining of the small intestine, which are responsible for the absorption of food into the bloodstream.