Say Hello To The Bugs In Your Gut.(obesity and intestinal microbiology)

Byline: Patrick J. Skerrett And W. Allan Walker, M.D.

Your small and large intestines are home to countless microbes that some scientists think may play a major role in determining how fat or skinny you are.

Whenever you eat, even if it's just a bowl of cereal while standing at the kitchen counter, you're feasting with trillions of your closest compadres. Bacteria, fungi and other microbes share the bounty as food churns through the vital inner tube that makes up your gut. It isn't a one-way relationship. These microscopic critters are essential contributors to our good health. They break down toxins, manufacture some vitamins and essential amino acids, educate the immune system and form a barrier against infective invaders. A provocative new avenue of research suggests that the makeup of microbes in the gut may influence our weight, too. If true, this could provide new strategies for weight control.

Which species of microbes live in the gut and what they do in there are just two of the many key questions that scientists are asking about this largely unexplored realm. "The landscape of the human gut is truly terra incognita," says Jeffrey Gordon, a genome scientist at Washington University in St. Louis whose research team is spearheading this effort. "The menagerie of microscopic organisms living there acts like an organ that carries out functions that we humans have not had to evolve."

The early work on our gut microbiota (loosely translated from Latin as "community of tiny living things") is challenging our notion of what it means to be human. From an early age, the human body is home to a huge but ever-changing…