The human microbiome consists of about 100 trillion microbial cells, outnumbering human cells 10 to 1.[55] It can significantly affect human physiology. For example, in healthy individuals the microbiota provide a wide range of metabolic functions that humans lack.[56] In diseased individuals altered microbiota are associated with diseases such as neonatal necrotizing enterocolitis,[57] inflammatory bowel disease[58] and vaginosis.[59]