Clinical and Microbiological Effect of a Multispecies Probiotic Supplementation in Celiac Patients With Persistent IBS-type Symptoms

Adults with celiac disease who were adherent to a strict gluten-free diet and had persistent IBS-type symptoms were enrolled in an Italian randomized, placebo-controlled trial conducted at gastroenterology units in Bari, Castellana Grotte, Foggia, and Taranto from 2013 to 2015. The active probiotic arm included 54 randomized participants in a 1:1 blocked allocation design.

A multispecies probiotic sachet was taken once daily for 6 weeks. Each sachet contained Lactobacillus casei LMG 101/37 P-17504 (5×10^9 CFU), Lactobacillus plantarum CECT 4528 (5×10^9 CFU), Bifidobacterium animalis subsp. lactis Bi1 LMG P-17502 (10×10^9 CFU), Bifidobacterium breve Bbr8 LMG P-17501 (10×10^9 CFU), and Bifidobacterium breve Bl10 LMG P-17500 (10×10^9 CFU); route of administration was not stated.

A 6-week multispecies probiotic improved IBS-type symptom severity versus placebo and was associated with microbiota changes, including an increase in bifidobacteria, with no adverse events reported. IBS-SSS fell from 295 ± 84.9 to 170.1 ± 53.4 in the probiotic arm, with a delta over baseline of -15.9% ± 14.8% (P = 0.008), and treatment success was higher than placebo in both ITT analysis (14.8% vs 3.6%, P < 0.04) and per protocol analysis (15.3% vs 3.8%, P < 0.04). GSRS also favored probiotics (12.2 ± 5.5 vs 16.7 ± 6.7 at end of treatment; P = 0.001), and Bristol Stool Charts improved (2.2 ± 1.3 vs 3.1 ± 1.9; P = 0.01). IBS-QOL did not differ significantly.

The trial was short, lasting only 6 weeks, and the active arm sample was modest. It was conducted in a limited geographic setting among adults with celiac disease on long-term gluten-free diets, which may reduce generalizability. IBS-QOL did not improve significantly, and longer-term clinical and mechanistic effects remain uncertain.