Industrial, not fruit fructose intake is associated with the severity of liver fibrosis in genotype 1 chronic hepatitis C patients

Abstract

To the Editor: Prof. Kitson’s comments give us the opportunity to clarify some issues that were not completely dealt with in our manuscript. In the study we reported a link between fructose intake and the severity of liver fibrosis in a cohort of Italian patients with genotype 1 chronic hepatitis C (CHC) [1], with an association found for industrial, but not for fruit fructose intake. Our results were in keeping with data already reported in patients with nonalcoholic fatty liver disease [2,3]. Prof. Kitson and his colleagues question firstly the appropriateness of using a web-based calculator of U.S. origin (www.healthdiet.us/fructose) to assess fructose intake in the Italian population, due to a presumed much lower fructose consumption in the latter. Actually, we considered industrial fructose as any amount of fructose derived from food sources containing high fructose corn syrup (beverages like soft drink and fruit juices, processed foods like fast-food, especially when enriched with industrial sauces). The U.S. database for the calculation of fructose intake is most likely valid also for use in Italian patients, since the majority of foods and beverages with added fructose are produced by multinational companies, and the concentration of fructose does not change among countries. In addition, our data on fructose consumption are in keeping with another Italian report [4]. Prof. Kitson and colleagues also question the validity of a three-day food diary. It has been reported that a three-day diary record correlates closely with a longer 9-day diary [5], providing a solid dietary assessment. In a cross-sectional analysis no inference can be made regarding a possible causal relationship, but this possibility may be postulated. We have simply described the positive association between industrial fructose and advanced fibrosis, but the two conditions might also share common pathogenic mechanisms. As a second point, our study was performed in an Italian population, not in an Australian or U.S. population, where much higher rates of fructose consumption are recorded. The accuracy of our computation of fructose intake is in keeping with the industrial fructose intake reported in the Italian population [4], Open access under CC BY-NC-ND license.