With trillions of bacteria, each with their own thousands of genes, the microbiome is like a four-pound superorganism living inside of you. These bacteria digest much of the fiber we eat, using enzymes our own cells can’t make and producing short-chain fatty acids that our cells absorb and use for energy. Our microbiome also digests other stuff that escapes the small intestine, aids in immune system activity, helps produce vitamins and other essential nutrients, and keeps the digestive tract running properly.
