How can we digest a seemingly huge variety of foods at the same time?
I was at a wedding function and there were all kinds of foods, milk based, solids, hot, cold, meat, desserts and of course raw meats and veggies. It boggles my mind how our intestine can digest all of these if eaten at the same time. How did we get to this? I don’t seem to know any other species capable of this.
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we have a wide variety of bacteria living in our guts that help with digestion, as well as different enzymes for different kinds of foods. (lactose intolerance means lack of enzyme for digesting dairy).
More broadly humans and many other apes are omnivores, we evolved to eat lots of different things, depending on what is available in a given location and season. Bears and pigs are omnivores too.
Those foods are made up of a relatively small number of types of molecule. Most of the molecules in food are starches, proteins, or fats, and your digestive tract contains enzymes that attack those whole classes of molecule. Specifically:
* Your saliva contains amylase(s), a (class of) enzymes that break down starches. Usually you don’t chew for long enough for this process to complete, but this breakdown is why starches taste sweet.
* Your gastric juices (“stomach acid”, but acid isn’t all it is) contain pepsin, an enzyme that breaks down proteins.
* And then your upper small intestine contains bile from your liver (which breaks down fats) and pancreatic juice (which contains multiple enzymes that break down all three of fats, proteins, and starches).
All of those various different foods really aren’t all that different at a molecular level. At the end of the day, most foods are just a series of carbon, hydrogen, oxygen, and nitrogen molecules strung together in different ways.
When it enters your stomach acid, the foods will all be broken down into those component parts. Most mammal stomachs and intestines can break down these basic components pretty easily.
All those foods are goupy slime after your stomach is done with them. Think of a brown-green soup when you throw up – all digestible food turns into that in your gut.
Imagine if you had a lego house made up of red, blue, yellow and green lego blocks. You want to make a car that is red, blue and yellow. What do you do?
You break apart the lego house, then pick out the pieces you want. All the green pieces that you won’t use for the car, get put to the side.
When you eat, you break apart the food with chewing, acid and enzymes. Then your intestines pick out the parts that it wants. Proteins, fats, carbohydrates, vitamins and minerals. All the parts that it doesn’t use, get pooped out.
While carnivores/herbivores specialize in eating certain things they can still digest some of the stuff that’s outside their typical diet.
Omnivores have a more generalist diet. Humans, pigs, dogs, chickens, raccoons, bears, ants, mice, catfish and tons of other animals out there could have eaten most, if not all, of the food that you had at that wedding.
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