Effects of dietary education, followed by a tailored fructose-restricted diet in adults with fructose malabsorption

OBJECTIVE: Fructose is absorbed by GLUT transporters in the small intestine. If this process is inadequate, abdominal symptoms because of fructose intolerance may arise. The effect of a tailored fructose-restricted diet on gastrointestinal complaints was assessed in patients with fructose intolerance. MATERIALS AND METHODS: Following an abnormal fructose breath test (50 g), 107 patients (64 also with lactose intolerance) entered three study periods: weeks 0-32 (free diet), weeks 32-36 (progressive increasing amount of fructose up to quantity inducing symptoms, 'trigger dose'), and weeks 36-48 (tailored fructose-restricted diet according to the 'trigger dose'). A subgroup of 15 patients underwent additional fructose breath tests (35, 25 g) to compare three different doses. RESULTS: At baseline, the most frequent symptoms were bloating and abdominal pain, and were more severe with combined fructose and lactose intolerance. During the free diet, patients reported eliminating (48%) or reducing (52%) fructose-containing foods, with a significant improvement in symptoms (abdominal pain from 79.7 +/- 1.3 to 19.3 +/- 1.8 mm; bloating from 83.1 +/- 1.3 to 19.4 +/- 1.8 mm; number of evacuations/day from 3.9 +/- 0.16 to 1.1 +/- 0.04; Bristol score from 5.1 +/- 0.14 to 3.8 +/- 0.1, P < 0.00001). During the tailored fructose-restricted diet, the consistent improvement in symptoms persisted and was similar to the improvement on free diet (abdominal pain 23.6 +/- 1.9 mm; bloating 19.4 +/- 1.8 mm; number of evacuations/day 1.7 +/- 0.07; Bristol score 3.5 +/- 0.06, P<0.00001 vs. baseline). A dose-dependent effect of fructose was observed on symptoms during the fructose breath test. CONCLUSION: In our setting, individuals with fructose intolerance show an inappropriate dietary self-management. By contrast, a tailored fructose-restricted diet improves gastrointestinal symptoms without senseless food deprivation.