Previous studies showed that high FODMAP meals induced a higher frequency of transient lower esophageal sphincter relaxation and reflux symptoms in patients with overlapping IBS and GERD. We aim to evaluate low FODMAP dietary advice efficacy for GERD patients with normal and abnormal 2-H postprandial reflux.
Methods: Patients with typical reflux symptoms, who had baseline Reflux Disease Questionnaire (RDQ) score >3 after 2-week run-in without acid suppressants and consuming >7 FODMAP items/week, were randomized to SILFD plus usual advice (SILFD+) vs. usual advice alone (UA). Patients with overlapping IBS per Rome IV criteria, were excluded. SILFD+ included identifying high-FODMAP items from the 7-day diary and replacing them with low-FODMAP ones by choosing from the provided menu. UA included weight reduction for obese patients, avoiding late meals, refraining from smoking, and elevating the head of the bed for nighttime symptoms. Responders were defined as those with an RDQ score ≤3 at week 4. Gastrointestinal Quality of Life Index (GIQLI) and 2-H pH-impedance study after lunch, along with H2 breath tests after self-prepared breakfast and lunch, were compared between 2 groups. Abnormal postprandial reflux was defined as ≥6 reflux episodes/2-H post-lunch.
Results: 38 patients were enrolled [20 SILFD+: 14F, age 51(32-65); 18 UA: 15F, age 48(35-59)]. Baseline RDQ score, and number of FODMAP items/week were similar between groups. Both groups showed significant improvements in RDQ and GIQLI scores at week 4, with no significant differences between groups (p>0.05). Prevalence of responders was similar (SILFD+ 25% vs. UA 22.2%, p>0.05). After 4 weeks, SILFD+ group showed a significant lower number of FODMAP item intake (16 vs. 24 items/week, p<0.001) and lower post-lunch breath H2 at 15 minutes, p =0.04. Six patients were excluded from pH-impedance analysis because they took <50% of usual meals. There were 13 patients [age 49(30-61), 13F] with normal and 19 [age 41(34-58), 13F) with abnormal baseline postprandial reflux frequency. In abnormal baseline postprandial reflux group, at week 4, SILFD+ group (n=10) exhibited a significantly lower postprandial reflux frequency [5(2.8-8) vs. 8(5.5-13.5) times/2-H, p=0.02] and tended to have lower acid contact time than UA group (n=9) [22.5 (7.9-37.9) vs. 45.8 (26.5-97.1), p=0.08]. In contrast, there were no significant different between post-treatment postprandial reflux frequency and acid contact time in normal baseline postprandial reflux group (p>0.05).
Conclusion: SILFD+ significantly reduced FODMAP intake and lower postprandial breath H2 than usual advice. In GERD patients with frequent postprandial reflux, SILFD was associated with a significantly lower postprandial reflux frequency. These findings highlight the potential benefits of incorporating low FODMAP dietary advice in the management of GERD.

Table 1: baseline characteristics and outcomes at 4-week in patients with abnormal and normal baseline postprandial reflux comparing between Structural Individual Low FODMAP Dietary Advice plus usual advice (SILFD+) vs. usual advice