Relationships between barley consumption and gut microbiome characteristics in a healthy Japanese population: a cross-sectional study

Abstract

Background Barley contains abundant soluble beta-glucan fibers, which have established health benefits. In addition, the health benefits conferred by the gut bacteria have attracted considerable interest. However, few studies have focused on the barley consumption and gut bacteria of the Japanese population. In this study, we aimed to identify the relationship between the barley consumption and gut bacteria composition of the Japanese population. Methods In total, 236 participants were recruited in Japan, and 94 participants with no complications of diabetes, hypertension, or dyslipidemia were selected for the study. We analyzed fecal samples from the participants, their medical check-up results, and responses to questionnaires about dietary habits. The participants were grouped according to their median barley consumption. Then, we assessed the relative abundance of 50 genera. Characteristic bacteria were evaluated for their relationship with barley consumption by multiple regression analysis, adjusted for disease and dietary habits, in all participants. We also analyzed the networks and clustering of the 20 selected genera. Results According to the comparison between barley groups, Bifidobacterium, Butyricicoccus, Collinsella, Ruminococcus 2, and Dialister were characteristic candidate bacterias of the group that consumed large amounts of barley (P < 0.05). The relationship between barley consumption and Bifidobacterium remained after adjusting for disease and dietary habits, and that of Butyricicoccus remained after adjusting for disease. Furthermore, network and cluster analyses revealed that barley consumption was directly correlated with Bifidobacterium and Butyricicoccus. Conclusions Barley consumption generates changes in the intestinal bacteria of the Japanese population. We found that Bifidobacterium and Butyricicoccus abundance was positively associated with barley consumption.

Gut dysbiosis in autoimmune diseases: Association with mortality

“…In contrast, Ruminococcus_2 is associated with the improvement of metabolic dysfunction. For example, the consumption of barley for eight months in subjects with metabolic dysfunction improved blood sugar levels and cholesterol levels, which accompanied the enrichment of Ruminococcus_2 and Dialister in the subjects' gut (Matsuoka et al, 2022). This suggests that the depletion of these commensal bacteria may be associated with the development of metabolic dysfunction.…”

“…Thus, B. fragilis enrichment in patients with SLE might be associated with enterotoxigenic strains. Among the 22 altered gut bacterial genera, Bacteroides, Escherichia, Ruminococcus, and Streptococcus have known functions associated with the induction of inflammatory response or autoimmunity in immune-related diseases (Vatanen et al, 2016;Cunningham, 2019;Henke et al, 2019;Qiu et al, 2019), whereas Faecalibacterium and Ruminococcus_2 have anti-inflammatory mechanisms of action (Houtman et al, 2022;Matsuoka et al, 2022). More details about this phenomenon have been described in Section 2.6.…”

Ruminococcaceae_UCG-013 Promotes Obesity Resistance in Mice

“…A significant negative correlation was found between Ruminococcaceae_UCG-013 and TG levels and a significant positive correlation was found between HDL-C and Ruminococcaceae_UCG-013 [ 40 ]. By interacting with barley, Ruminococcaceae_UCG-013 may ameliorate dyslipidemia in people with a high barley intake [ 41 , 42 ]. Based on a cross-sectional study on the relationship between the gut microbiota and childhood obesity, Ruminococcaceae_UCG_013 may play an important role in weight loss in children [ 43 ].…”

Characteristic Gut Bacteria in High Barley Consuming Japanese Individuals without Hypertension

“…Individual differences in the impact on host health are a crucial problem of functional foods [ 15 , 16 ] that has been recently explained, although partially, by the microbiome composition. Barley contains high levels of β-glucan, a soluble dietary fiber, and is a food with potential functions to improve gut bacteria [ 17 , 18 ] and lower postprandial blood glucose levels [ 19 , 20 ]. However, a meta-analysis of 18 randomized control studies suggests that the anti-diabetic effects of β-glucan vary by regions and disease history [ 21 ].…”