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Alexa Evenson


Perceived Stress, Cortisol, Breath Hydrogen, and Gastrointestinal Symptoms After Consumption of Gluten and Inulin in Adults With and Without Irritable Bowel Syndrome. S.L. Stovern, L.P. Metelmann, J.R. Milstroh, and A.L. Evenson, PhD., RDN, CFS. Nutrition Department. College of Saint Benedict/Saint John's University, Saint Joseph, MN.

Background: Stress is often thought to play a role in breath hydrogen and gastrointestinal symptoms.

Objective: Investigate the relationship between cortisol, perceived stress, breath hydrogen, and gastrointestinal symptoms after consumption of gluten and inulin in those with and without IBS.

Methods: A randomized, controlled crossover design was conducted with 24 non-IBS and 14 IBS participants. Fasted participants consumed a control low FODMAP smoothie and treatment smoothies that consisted of the low FODMAP base (control) with gluten (5g) or inulin (5g). Cortisol and breath hydrogen were measured at baseline (0), 1, 2, and 3 hours. GI symptoms were measured at baseline (0), 0.5, 1, 1.5, 2, 3, 12, and 24 hours. Perceived stress was measured for each treatment. Salimetrics ELISA assays were used to determine cortisol values. Variables were analyzed by the Area Under the Curve, Spearman rho, Repeated Measures ANOVA, and Simple Effect Tests with significance set at p<0.05.

Results: Cortisol differed in the non-IBS group between control vs gluten treatments (MD=-0.313; p=0.004) and control vs inulin treatments (MD=-0.150; p=0.031), with control having lower cortisol concentrations. Perceived stress did not differ between treatments or IBS groups (p>0.05). GI symptoms differed between gluten and inulin treatments in non-IBS group, with gluten producing fewer GI symptoms (MD=-4.362; p=0.013). IBS group had more total GI symptoms than non-IBS group for control (MD=73.219; p=0.001), gluten (MD=54.571; p<0.001), and inulin (MD=56.338; p=0.032) treatments. There were no differences in breath hydrogen between treatments or groups (p>0.05).

Conclusion: In this sample of participants, the restriction of gluten and inulin in the diet (at 5 grams) is not warranted for those with and without IBS, as neither treatment produced a significant increase in breath hydrogen or GI symptoms. In those with IBS, there were increased GI symptoms to start with, indicating more GI distress but not related to the consumption of gluten or inulin at the 5-gram level. While perceived stress did not differ between non-IBS and IBS groups, physiological stress (cortisol) was higher with gluten consumption in non-IBS participants. More research is needed as the relationship between cortisol, breath hydrogen, and GI symptoms is still unclear.