Dietary plants, gut microbiota, and obesity: Effects and mechanisms

Obesity is a leading contributor to numerous diseases, such as diabetes mellitus, cardiovascular diseases, and cancers. Therefore, seeking effective and safe approaches to control obesity is essential. Gut microbiota has been demonstrated to play a critical role in the occurrence of obesity via the regulation of energy metabolism. The composition and abundance of gut microbiota can be altered by the diet. Recently, many dietary plants have been demonstrated to exert anti-obesity effects through bioactive components that modulate gut microbiota, which has drawn increasing research attention. In this review, the obesity-associated gut microbiota has been summarized and classified into obesogenic and anti-obesity categories. Subsequently, some anti-obesity dietary plants with gut microbiota-modulating activities and the mechanisms of action of their bioactive components are discussed. The effects of gut microbiota on obesity have been found in most animal and some human studies. Certain strains of Firmicutes, Lactobacillus, and Bacteroidetes are positively associated with obesity development, while Bifidobacterium, most Lactobacillus, and some Bacteroidetes show anti-obesity activities. Some dietary plants, such as grapes, berries, apple, turmeric, chili, soy, sorghum, and barley, show anti-obesity efficacy through increasing the diversity of gut microbiota, up-regulating anti-obesity gut microbiota and down-regulating obesogenic gut microbiota. This review may stimulate further development of functional foods to treat obesity through modulating gut microbiota. Future work will rely on the exploration of more dietary plants and their components with anti-obesity and gut microbiota-modulating effects, and further investigation of related mechanisms as well as clinical trials.