Does Whole Grain Consumption Alter Gut Microbiota and Satiety?

Abstract

This review summarizes recent studies examining whole grain consumption and its effect on gut microbiota and satiety in healthy humans. Studies comparing whole grains to their refined grain counterparts were considered, as were studies comparing different grain types. Possible mechanisms linking microbial metabolism and satiety are described. Clinical trials show that whole grain wheat, maize, and barley alter the human gut microbiota, but these findings are based on a few studies that do not include satiety components, so no functional claims between microbiota and satiety can be made. Ten satiety trials were evaluated and provide evidence that whole oats, barley, and rye can increase satiety, whereas the evidence for whole wheat and maize is not compelling. There are many gaps in the literature; no one clinical trial has examined the effects of whole grains on satiety and gut microbiota together. Once understanding the impact of whole grains on satiety and microbiota is more developed, then particular grains might be used for better appetite control. With this information at hand, healthcare professionals could make individual dietary recommendations that promote satiety and contribute to weight control.

Keywords: VAS appetite assessment; bile acids; gut microbiota; obesity; satiety; short chain fatty acids; whole grains.

Figure 1

Percent of per capita availability of cereal grains in the United States. Data from the USDA Economic Research Service, 2012 [20].

Figure 2

Products that contributed to adult whole grain intake. Data represent the average consumption of different categories of whole grain foods from the National Health and Nutrition Examination Survey (NHANES) 2009–2010 [11].