Elevated fructose in the intestines of fructose malabsorbers is thought to react with dietary proteins to form digestion resistant fragments (known as fru-AGEs). Once formed they may gain access to the blood stream (via the lymphatics) and bind receptors (RAGE) known to be enriched in the lungs, and associated with inflammation and mucus hypersecretion of the airways. The potential role that fru-AGEs and RAGE may have in triggering aberrant respiratory symptomology in fructose malabsorbers is consistent with the directional flow of fructose modified dietary peptides. Specifically, the mechanistic flow is consistent with fru-AGEs crossing the intestinal barrier, traveling back to the blood circulation via the lymphatics, back to the heart, and onto to the pulmonary circuit of the lungs. The lungs are the human tissue known to have the highest concentrations of receptors (RAGE) of fru-AGEs.
Current research indicates that RAGE over-expression occurs in all pathological conditions associated with RAGE binding and may have a role in chronic lung diseases. How these receptors contribute to pro-inflammatory disease states is a very active area of research.
Elevated fru-AGE in sera of fructose malabsorbers is thought to trigger symptoms associated with fructositis disease including dry cough, mucus hypersecretion of the airways, airway hyperreactivity, chronic bronchitis, and asthma.