Effect of oat ß-glucan of different molecular weights on fecal bile acids, urine metabolites and pressure in the digestive tract - A human cross over trial.

While the development of oat products often requires altered molecular weight (MW) of ß-glucan, the resulting health implications are currently unclear. This 3-leg crossover trial (n = 14) investigated the effects of the consumption of oat bran with High, Medium and Low MW ß-glucan (average > 1000, 524 and 82 kDa respectively) with 3 consequent meals on oat-derived phenolic compounds in urine (UHPLC-MS/MS), bile acids in feces (UHPLC-QTOF), gastrointestinal conditions (ingestible capsule), and perceived gut well-being. Urine excretion of ferulic acid was higher (p < 0.001, p < 0.001), and the fecal excretion of deoxycholic (p < 0.03, p < 0.02) and chenodeoxycholic (p < 0.06, p < 0.02) acids lower after consumption of Low MW ß-glucan compared with both Medium and High MW ß-glucan. Duodenal pressure was higher after consumption of High MW ß-glucan compared to Medium (p < 0.041) and Low (p < 0.022) MW ß-glucan. The MW of ß-glucan did not affect gut well-being, but the perceptions between females and males differed.

Diet, Perceived Intestinal Well-Being and Compositions of Fecal Microbiota and Short Chain Fatty Acids in Oat-Using Subjects with Celiac Disease or Gluten Sensitivity.

A gluten-free diet may result in high fat and low fiber intake and thus lead to unbalanced microbiota. This study characterized fecal microbiota profiles by 16S MiSeq sequencing among oat-using healthy adult subjects (n = 14) or adult subjects with celiac disease (CeD) (n = 19) or non-celiac gluten sensitivity (NCGS) (n = 10). Selected microbial metabolites, self-reported 4d food diaries and perceived gut symptoms were compared. Subjects with NCGS experienced the highest amount of gut symptoms and received more energy from fat and less from carbohydrates than healthy and CeD subjects. Oat consumption resulted in reaching the lower limit of the recommended fiber intake. Frequent consumption of gluten-free pure oats did not result in microbiota dysbiosis in subjects with CeD or NCGS. Thus, the high number of gut symptoms in NCGS subjects was not linked to the microbiota. The proportion of fecal acetate was higher in healthy when compared to NCGS subjects, which may be linked to a higher abundance of Bifidobacterium in the control group compared to NCGS and CeD subjects. Propionate, butyrate and ammonia production and ß-glucuronidase activity were comparable among the study groups. The results suggest that pure oats have great potential as the basis of a gluten-free diet and warrant further studies in minor microbiota disorders.