Gut microbiota, dietary phytochemicals and benefits to human health

In this review, we discuss the roles of the gut microbiota, dietary phytochemicals in improving human health. Recent studies have reported that the human gut microbiota can be altered by dietary phytochemicals including phenolics, carotenoids, and dietary fibers. In addition, both pathogenic and nonpathogenic bacteria show regulatory effects with phytochemicals, suggesting potential synergistic effects in the improvement of human gut health and prevention of chronic diseases.

Numerous studies have been conducted on gut microbial alterations induced by phytochemicals, such as phenolics and carotenoids. Butyrate, a short-chain fatty acid produced via bacterial fermentation in the colon, also shows a significantly beneficial effect in the maintenance of gut microbial homeostasis. However, the molecular mechanisms underlying the effects of diets and the interactions of the gut microorganisms remain poorly understood. The gut microbiome profile changes have been observed in chronic inflammation-induced diseases including colitis, Crohn's disease, immune dysfunction, colon cancer, obesity and diabetes. The anti-inflammatory effects of dietary phytochemicals against these diseases may be partially mediated by regulation of microbial profiles. Latest advances in biomedical technology such as the next-generation sequencing (NGS), and continuous cost reduction associated with these technologies, enabled researchers to perform ever-increasing number of large-scale, high-throughput computational analyses to elucidate the potential mechanism of phytochemical-microbiome interactions.

Information obtained from these studies may provide valuable insights to guide future clinical research for the development of therapeutics, botanicals and drug efficacy testing, many of which will be discussed in this review.