Short-term intake of fiber-rich oat bran but not spelt bran flake mix lowers bacterial endotoxin levels and improves health parameters in healthy, normal weight, young to middle-aged women

Diets low in dietary fiber have been associated with higher risks for non-communicable chronic diseases. We assessed in a single-blinded cross-over designed study if oat bran and spelt bran rich flake mixes, respectively, are suitable to increase general fiber intake in healthy women and impact intestinal microbiota composition, markers of intestinal barrier function, and general health parameters. Both interventions were associated with a significant increase in overall fiber intake but no marked changes of nutrient intake. Blood pressure was significantly lower after both interventions whereas cholesterol levels, alanine transaminase and aspartate transaminase activities in serum were only lower after the oat bran mix intervention. The latter was associated with a significant decrease of bacterial endotoxin in plasma but no change in intestinal microbiota composition. Our study suggests that fiber rich flake mixes are a suitable measure to increase dietary fiber intake, but health effects may differ between different dietary fibers.