Abstract

Human health cannot be understood without considering the associated microbes, designated microbiota. Some ofthe recognized health-stimulating dietary ingredients, the pre- and probiotics, may affect consumer health either directly or viamodulation of its intestinal microbiota. The introduction of new molecular technologies, such as bar-coded pyrosequencing, hascreated a revolution in our capabilities to describe and understand the intestinal microbiota. We have discovered thousands ofspecies in a composition that is determined by a variety of factors, including anatomical location within the intestine, thegenetics of the host, the diet, and the health status. The microbiota description beyond the level of its species composition isemerging, and includes determination of its genetic content and most importantly its (metabolic) activity. The current challengeis to recognize which microbial interactions principally drive our health, or in other words, to decipher the causal relationsbetween the microbiota composition and function in relation to human health or disease. Such knowledge can be used todevelop diagnostic tools that assist in determination of a person’s health status, but can also provide leads to improve a person’shealth through dietary or pharmaceutical interventions.