Most of us have a blurry idea of how digestion works: we eat food, break it down (that’s the scientific term, right?) and, somehow, profit. But without a better understanding of what goes on in there, we’re liable to believe a few bizarre myths that have become common.
Our digestive tract is a complex system with many parts that communicate with each other and the rest of our body. It’s also very adaptable to what we consume, and doesn’t need specific food combinations or “cleanses” to keep working at its best. Here is a myth about digestion, debunked by Dr. Bhatti.
Some digestion happens in the stomach, but food passes through a series of stations on its way through our body, of which the stomach is only one. Here’s the cheat sheet:
The mouth is the first stop, and actually plays an important role. Tastes and smells signal the rest of the digestive system that food is on its way. We chew food to give it more surface area (the better for enzymes later on to do their job) and saliva helps us taste and swallow, as well as keeping our mouth healthy in between meals.
A swallow sends food on a trip down the esophagus, which pushes it tube-of- toothpaste style toward the stomach. (The trip takes about eight seconds.) This motion, called peristalsis, ends by triggering the stomach’s entrance to open.
In the stomach, food is drenched in an acid wash. This helps to kill microbes and partially unravel proteins. A few enzymes, specialized to work in the acid environment, can do their jobs: mainly chopping up proteins.
The small intestine is actually where most of this action happens: enzymes breaks down fats, proteins, and carbohydrates into their components (fatty acids, amino acids, and sugars, respectively). Giving the body tiny building blocks instead of large chunks of macronutrients, allowing the small intestine’s cells to absorb them and pass them through to the bloodstream. From there, they are transported to where they are needed. We either burn them for energy, store them as fat, or in some scenarios, use them to build components of our own bodies—like when we use the amino acids from food protein to build more actin and myosin in our muscles.
In the large intestine, trillions of microbes devour what we couldn’t—mainly fiber and other “prebiotic” carbohydrates. That’s good news for us, since these microbes’ waste products are essential to our health. They’re where we get most of our vitamin K, for instance.
The whole process of digestion is mysterious and awesome, and way bigger than what happens in any one organ. The entire route your food takes is known as your gastrointestinal (or GI) tract, and scientists often call it simply the “gut.”