Sugar and the Mosaic of Autoimmunity.

BACKGROUND Recent discoveries in the field of immunometabolism, and on the role of the serine-threonine kinase mTOR as a sensor of nutrients, integrator of cellular signaling pathways, and regulator of metabolism, have widened our understanding of the connection between nutrition, health, and diseases. Epidemiological studies have shown that higher sugar-sweetened beverage consumption is associated with increased risk of developing chronic diseases, including cardiovascular disease, type 2 diabetes mellitus, obesity, non-alcoholic fatty liver disease, gout, and rheumatoid arthritis and to worse symptoms in some patients with rheumatoid arthritis. Anabolic metabolism has been demonstrated to favor the differentiation of proinflammatory T lymphocytes while katabolic metabolism to favor regulatory T lymphocyte differentiation. CASE REPORT In a 66-year old male, the onset of gonarthritis and enthesitis and worsening of these symptoms 3 months later were associated with excessive intake of desserts. Two weeks after starting strict avoidance of sugar containing nutrients and beverages symptoms disappeared. During the next 6 months, on 3 occasions, the exceptional consumption of a dessert was followed by a mild and transient recurrence of the symptoms. CONCLUSIONS The repeatedly observed recurrence of enthesitis/arthritis symptoms following sugar intake and its disappearance following avoidance of sugar, represents an extreme example of a link between metabolism and local inflammation in the reported individual. The rapid absorption of the monosaccharides glucose and fructose from the intestine, where they derive from hydrolysis of the disaccharide sucrose (sugar) might lead to overactivation of mTOR if not counterbalanced by other mTOR interfering mechanisms.