The bacteria of the human digestive system have been likened to tiny factories that ingest raw materials — food — and processing them into finished products — nutrients — that our bodies can absorb and use. In fact, many of the complex carbohydrates and proteins critical for life cannot be absorbed unless first digested by bacteria. Yes, we may all be stardust, but not, it seems, before we are microbial excrement.
Scientists refer to this complex community as the “gut biome,” a stew of hundreds, perhaps thousands of species of bacteria that live in the human gastrointestinal tract. Like many communities, not all inhabitants are there for good. Sometimes, things go awry. Understanding what happens then, and how to correct things when they do, is the life work of Stanford’s Michael Fischbach, associate professor of bioengineering.
Fischbach says that many afflictions, from Crohn’s to cardiovascular disease, may be caused by dysfunction or imbalances in our microbial communities. The solutions, ranging from the severe, such as scorched-earth antibiotics that kill everything in sight, to the creative, such as fecal transplants from healthy guts to ill, are reshaping our understanding of life and medicine.