The small intestine is the organ where most of the action related to Fructositis disease is thought to occur. When Fructose Malabsorbers fail to adequately absorb excess free fructose, levels build, become concentrated and reactive. It is thought that in this environment, fructose when combined with dietary proteins can undergo a chemical reaction referred to as the Maillard Reaction. This reaction is thought to be implicated in the biochemical pathway leading to Fructositis Disease. It may yield well studied end products, known as Advanced Glycation End-products (AGE), which presently serve as bio-markers for average blood glucose levels in diabetic patients and are measured via a test known as Hba1c. In Fructositis disease conditions in the small intestine (pH 8–9) appear favorable for the reaction.
Research indicates that fructose contributes to AGE formation more than glucose. It has been estimated that fructose produces ten times more AGEs than does glucose.