The Effect of Bacillus coagulans Induced Interactions among Intestinal Bacteria, Metabolites, and Inflammatory Molecules in Improving Natural Skin Aging

Background: Lactic acid bacteria consumption serves several health benefits to humans. However, their effect on natural skin aging is still unclear. Methods: This study examined the effects of skin naturalization (particularly skin drying) by administering a spore-bearing lactic acid bacteria (Bacillus coagulans) in mice for 2 years. Results: B. coagulans administration improved the natural skin of mice and significantly increased proportions of the genera Bacteroides and Muribaculum, among other intestinal bacteria. As metabolites, increases in nicotinic acid, putrescin, and pantothenic acid levels and a decrease in choline levels were observed. Increased hyaluronic acid, interleukin-10, and M2 macrophage levels indicate aging-related molecules in the skin. Intestinal permeability was also suppressed. Thus, these changes together improved natural skin aging. Conclusions: This study revealed that B. coagulans administration improved the natural skin aging in mice. This enhancement might be induced by the interaction of alterations in intestinal flora, metabolites, or inflammatory substances.