Title says all. Plant cells are covered by cell wall made of cellulose. The human body doesn’t have the enzyme cellulase to digest it, so why do we eat them? Do they just pass through us? If so, why are they ‘healthy’?
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They contain other forms of energy as well. Cellulose is pretty low in energy, so to live off it we’d need to eat lots of it and slow down digestion. We favor more efficient nutrients like sugar, starch, fat and protein, luckily many plants include them too. (The plant stores energy in that form for example)
The cellulose just passes through us, and that is actually also not a bad thing, we know it as “fibre” wich helps our body flush stuff through our digestive tract.
Because we can get a variety of other vitamins and nutrients from them. There isn’t much in the cell wall for us to get, so it just passes through. Overall, plants are healthy for all the nutrients we get and the cellulose doesn’t hurt us.
The plant cell wall is made of cellulose, which we can’t digest. However, the plant cells also contain other nutrients like proteins and carbohydrates that we can digest.
Firstly we can break the cell walls by mechanical action, chewing. And then in the stomach the cell walls gets broken down by acid. The acid itself does not break down the cellulose and pectin and other molecules in the cell wall but changes them and breaks the connections between them. Essentially we are not destroying the bricks but picking away at the mortar between the bricks so we get through the wall. And we do not have to dissolve the entire cell wall to get to the content of the cell, we only need to get one hole in the cell wall to get the content out. And when the remains get into the later stages of digestion there are lots of bacteria and some of them might produce their own version of cellulase that can help digest cellulose for us. However most of the cellulose we eat still end up in the toilet, but with the content of the cell removed from it.
Humans have ability to cook food. That drastically alters bioavailability of nutrients and digestion is easier etc. Some might even go so far and say it’s one of the most important abilities that made us human.
Fiber is great for you. It’s where bacteria multiply well and maintain/develop your biome. Also this article.
https://labblog.uofmhealth.org/lab-report/gut-bacteria-eat-colon-lining-when-starved-for-fiber
Just because we can’t digest cellulose doesn’t mean it isn’t healthy for us. Herbivorous animals like cows produce cellulase to break down cellulose into sugar, because that’s how they sustain themselves on nothing but grass and other leafy plants all day long.
We, however, are omnivores and are adapted to have a much more diverse diet, so we don’t really need to digest cellulose. Cellulose still plays a role in our digestion precisely because it doesn’t get broken down, and because it is very absorbent. We rely on the presence of cellulose in our diet to retain water in our stool. Without it, you’ll tend to get extremely constipated because your intestines will extract too much water from your stool and it will become rigid.
Besides that, cellulose is only one form of carbohydrate in plants. There are also simple sugars and starches which we can digest, but in today’s society, getting enough carbs is usually the least of our concerns. That’s the real reason why vegetables that are low in carbs and high in other vital nutrients are generally considered the healthiest foods.
Why do we buy stuff in cardboard boxes, if we have no use for cardboard boxes?
Perhaps it’s the contents?
Or we move.
Humans only ate plants out of survival depending on the geographical location where there wasn’t much animal protein around. I don’t think plants want to be eaten, which is why they release “plant defense chemicals” which can be harmful to humans in large amounts.
I don’t see any real reason to eat plants when you can get all of the bioavailable nutrients you need from organic animal products.
“we” do very little of the actual digestion of our food. Most of it is done by the microbes living in our gut and the fiber in the plants gives them more surface area to grow and helps move things along so our guts can collect the nutrients easier
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