Dietary Patterns in a Nationwide Cohort of Patients with Hereditary Fructose Intolerance

Background/Objectives: Hereditary fructose intolerance (HFI) is an inherited metabolic disorder caused by a deficiency of the enzyme fructose-1,6-bisphosphate aldolase. Treatment consists of a lifelong diet restricted in fructose, sucrose, and sorbitol (FSS). The aim of this study was to determine dietary intake of FSS and to analyze the consumption patterns of vegetables, fruit, legumes, pulses, and dried fruit in a nationwide cohort of HFI patients. Methods: Overall, 36 HFI patients and 28 age-, sex- and BMI-matched healthy control subjects participated in this study. A self-administered three-day dietary record and an adapted quantitative food frequency questionnaire (FFQ) including frequency and portion sizes were collected. FSS intake was calculated using the DIAL Nutritional Calculation Program (ALCE INGENIERÍA). Total fructose intake was calculated as the sum of free fructose, 50% of sucrose, and sorbitol. Results: Protein intake was significantly higher in HFI patients compared to the controls (92.43 g/day [65.1-165.03] vs. 70.39 g/day [35.21-133.83]; p = 0.001). In most patients, total fructose intake was within the recommended limits (9.79 mg/kg bw/day [0.29-59.09]), with no significant differences between children and adults (p = 0.325). Although the established dietary recommendations did not always match the actual intake observed in a real-life setting, in general, foods with higher fructose content were consumed less frequently and in smaller quantities. Conclusions: Further research on the fructose content of various foods, particularly fruits and vegetables, and updated dietary recommendations for HFI patients are warranted to provide the best tools for the nutritional management of the disease.