Lactose and fructose malabsorption in children with recurrent abdominal pain: results of double-blinded testing

Aim: To investigate malabsorption of lactose and fructose as causes of recurrent abdominal pain (RAP). Methods: In 220 children (128 girls, mean age 8,8 4.1–16.0] years) with RAP, hydrogen breath tests (H₂BT; abnormal if ΔH₂ > 30 ppm) were performed with lactose and fructose. Disappearance of RAP with elimination, recurrence with provocation and disappearance with re‐elimination, followed by a 6‐month pain‐free follow‐up, were considered indicative of a causal relation with RAP. For definite proof, a double‐blinded placebo‐controlled (DBPC) provocation was performed. Results: Malabsorption of lactose was found in 57 of 210, of fructose in 79 of 121 patients. Pain disappeared upon elimination in 24/38 patients with lactose malabsorption, and in 32/49 with fructose malabsorption. Open provocation with lactose and fructose was positive in 7/23 and 13/31 patients. DBPC provocation in 6/7 and 8/13 patients was negative in all. However, several children continued to report abdominal symptoms upon intake of milk or fructose. Conclusion: Lactose intolerance nor fructose intolerance could be established as causes of RAP, according to preset criteria including elimination, open provocation and DBPC provocation. However, in clinical practice, persistent feeling of intolerance in some patients should be taken seriously and could warrant extended elimination with repeated challenges.