Excess free fructose, apple juice, high fructose corn syrup and childhood asthma risk – the National Children’s Study

BACKGROUND: Recent research provides consistent evidence that the unexplained doubling of childhood asthma prevalence (1980–1995), its continued climb and 2013 plateau, may be associated with the proliferation of high-fructose-corn-syrup (HFCS) in the US food supply. The HFCS used in soft drinks has been shown to contain a higher fructose-to-glucose ratio than previously thought. This coincides with a preference shift from orange to apple juice among young children. Apple juice naturally contains a high (≥2:1) fructose-to-glucose ratio. Thus, children have received high excess-free-fructose doses, the fructose type associated with fructose malabsorption. Unabsorbed excess-free-fructose in the gut may react with dietary proteins to form immunogens that bind asthma mediating receptors, and/or alter the microbiota towards a profile linked to lung disorders. Studies with longitudinal childhood data are lacking. Therefore, we tested the hypothesis that excess-free-fructose intake is associated with childhood asthma risk. METHODS: Cox regression models were used to analyze prospective early childhood data (12–30 months of age) from the National Children’s Study. Intake frequencies for soda/sports/fruit drinks, and 100% juices were used for analyses. RESULTS: Greater consumption of 100% juice, soda/sports/fruit drinks, and any combination, was associated with ~two (P = 0.001), ~ 2.5 (P = 0.001), and ~ 3.5 times (P < 0.0001) higher asthma incidence. CONCLUSIONS: Given these results, prior research and case-study evidence, it is reasonable to suggest that the two-fold higher asthma risk associated with 100% juice consumption is due to apple juice’s high fructose-to-glucose ratio, and that the ~ 2.5/~ 3.5 times higher risk associated with soda/sports/fruit drinks intake is with the excess-free-fructose in HFCS.