Questions tagged [digestion]

The physiological process of breaking down food into its constituent parts to provide nutrition for the body.

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Understanding certain limited biochemical impacts of egg yolk

I am researching the use of isolated egg yolk lecithin (EYL) in food preparation. I am interested in its ability to act as an emulsifier without having ancillary negative impacts. I am aware that some ...
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Does poop have protein?

Popular health advice suggests that one shouldn't consume >30g of protein at a time (without a gap of ~3 hours, or otherwise depending on the type of protein), because only so much can be digested ...
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Is ghrelin only secreted when the stomach is empty?

Several texts indicate that ghrelin is secreted when the stomach is empty. However, some(not all) texts also indicate that ghrelin is secreted when blood sugar levels are low. Is the second statement ...
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Would fewer cows mean less methane emission?

Rotting grass produces the same amount of methane as cows that digest grass (see this source). So if cows did not eat the grass, it would still emit methane. Therefore, if there were fewer cows, would ...
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Why is livestock bad for the climate?

It is always told that eating meat is bad for our climate. This is most often explained by mentioning following reasons (Source): Methane is produced when digesting the food and also the faeces of ...
Lockhart 's user avatar
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Why does biomagnification of mercury occur more in large fish?

I love tuna so this question has been bugging me senselessly. I am aware that larger fish tend to have more mercury concentration in their flesh than their prey, however, I don't understand how this ...
Jordan Regan's user avatar
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Is raw meat or raw vegetables easier for humans to digest?

Which one is easier for a human digestive system to digest, raw meat or raw vegetables? I have heard some of my friends who say that raw (or uncooked) meat is easier to digest than raw (or uncooked) ...
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is pepsin able to break down proteins into amino acids in human stomach? [closed]

I'm trying to find out if pepsin can break down proteins into amino acids after they are converted to peptides. Is pepsin able to separate amino acid monomers from the peptides? can you please show me ...
Parham Moieni's user avatar
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Why can't humans digest dietary fiber when we can digest starch?

So, I can see that there's a couple of questions touching on this subject already, but none of them answer the aspect that I'm curious about: Dietary fiber is a polymer composed of multiple starch ...
nick012000's user avatar
2 votes
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Does baking soda interfere with digestion when cooked into food?

Baking soda is useful for tenderizing meats and leavening baked goods. In the case of meats, it allegedly breaks down proteins/amino acids. However, does this usage pose a risk to digestion? Could the ...
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Does Chewing Food Properly Ensure that we gain Less Fat?

We recently went to a fast-food corner and I was told by my sibling that even if we chew a burger properly(slowly) converting it into a fine bolus, then it would not affect the amount of fat gained by ...
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How are monosaccharides and amino acids absorbed in jejunum?

Duodenum receives bile from liver and Pancreatic juice from pancreas. Intestinal glands secrete Intestinal juice which acts at the ileum. Most of the absorption of food materials takes place in the ...
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Does hydrolysis of carbohydrates, proteins, and fats occur in the small intestine?

Does the hydrolysis of carbohydrates, proteins, and fats occur in the small intestine? I have researched this and just cannot seem to get a clear-cut answer. Perhaps I am misunderstanding something? ...
ASA MATTHEWS's user avatar
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Why can we eat salty food, but can't stomach salty water?

I know that too much sodium is bad for our health. However, it struck me as odd that we like to add salt to pasta sauce or other foods we eat, yet trying to drink salt water can bring on the gag ...
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Parasympathetic effects on digestive tract - motility versus absorption

The parasympathetic nervous system's purpose is often referred to as "rest and digest." As part of this purpose, parasympathetic innervation increases motility in the digestive tract to move ...
Nicholas Hassan's user avatar
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Do Termites and Silverfish metabolize cellulose the same way?

I am fascinated with silverfish and would like to understand more about their metabolism. I learned that they can survive on a diet of cotton which is nearly pure cellulose. Do they metabolize ...
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What do spider digestive fluids look like?

What is the general appearance of the fluids that spiders use to digest their prey before they ingest it into the body?
Ichthys King's user avatar
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Why aren't the antibodies in the mother's milk digested by the infant's digestive system?

Why aren't the antibodies in the mother's milk digested by the infant's digestive system? Enzymes like pepsin have been found to be present in infant's digestive system(1). Though the pH in the ...
trinitrotoluene's user avatar
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Why do nattokinase and serratiopeptidase remain effective when given orally, but not insulin?

Why do nattokinase and serratiopeptidase not break down in the stomach and intestines? Article says that serratiopeptidase is absorbed in rats intestines after oral intake - https://iubmb....
Serhii Kushchenko's user avatar
1 vote
1 answer
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Do humans emit more carbon through respiration or defecation?

Where does most of the carbon we ingest go? I understand that a large amount is exhaled as carbon dioxide, but what percent is defecated (and theoretically deposited in the ground)?
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Why do vertebrates have an oesophagus?

As far as I know, the oesophagus in vertebrates has no digestive or absorptive function. It is simply a conduit from the mouth to more distal parts of the gastrointestinal tract. Why have it at all, ...
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How do Apes get their Omega 3s in the wild given so few plant sources? Are they able to convert it to DHA?

Given so few plant sources(around 6-7) of ALA, how do Apes get ALA in the wild? Are they able to convert it into DHA in satisfactory amounts?
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Does animal based food contain molecules that behave like dietary fiber for humans?

I have read that dietary fiber is beneficial to human health in many ways, for example that it can help to reduce risk of colorectal cancer. However, when I look at nutrition labels on food it seems ...
David Ruffner's user avatar
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Is the "first pass effect" diminished more by some foods than others?

This effect and its considerations are fairly well known but it's never been clear to me whether it's a greater consideration with some types of food than others.
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Relationship between immunologic response to specific gluten epitopes and clinical antibody testing

Celiac disease is understood to be an immune response to certain proteins which occur in a group of cereals; most commonly they are glutens (wheat), secalins (rye) and hordeins (barley). A clinical ...
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How are proteins reused in the body? [duplicate]

Part of what we eat are proteins, and our body is in part build of proteins. Are the proteins of the body build based on proteins in food at all? Are proteins in food directly reused in the body, or ...
Volker Siegel's user avatar
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What happens when a human ingests a large meal, and after a short time follows it up with a large amount of indigestible carbs?

A human eats a large meal and indigestible carbs (IC) with such a timing that the IC arrive to the small intestine when it is already full and busy breaking down and absorbing the meal. What would ...
budgiebeaks's user avatar
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Is brewer's yeast a good source of protein for humans?

I read that brewer's yeast protein is not a "real protein" and is not usable by non-ruminants. Is that true? If yes, how can I know what kind of protein is good for humans (especially athletes)
Sorb's user avatar
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Do we excrete waste in same order of food intake?

Obviously I do not expect we poop out molecule by molecule in exact order. All I am asking is, is it possible for us to pass stool's of today's food before we poop yesterday's food. Does our GI tract ...
Karthick S's user avatar
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Why are nutrients from food absorbed more efficiently? [duplicate]

It seems to be common knowledge that micronutrients such as vitamins are more easily absorbed by your body when in your diet versus supplements such as pills. I am wondering what the reasons for this ...
Jakob Abfalter's user avatar
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Cellulase Sample Digestion Protocol?

Is there an effective way to use cellulase(s) and/or lignase(s) to remove unwanted plant debris from a sample? I'm working with a series of fresh water grab samples for environmental assessment. The ...
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How can we digest lactose even though it has Beta glycosidic linkages?

I have Read that we cannot digest cellulose because we do not have enzymes to digest Beta glycosidic linkages in Cellulose Then how is it that we have an enzyme called Lactase to digest the Beta ...
Sudhanshu Bharadwaj's user avatar
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1 answer
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Human evolutionary innovation for rapidly restoring glycogen, and link to cardiovascular disease?

I'm a physicist, not a biologist, but I'm interested in human evolution and its link to the physiology of endurance sports. Circa August 2019, I read an article in the newspaper whose contents I'll ...
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7 votes
1 answer
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Why is sugar absorbed very fast into the blood stream?

Recently, I heard from a pregnant person I know that immediately after she eats something sugary/sweet, the baby starts kicking and moving around, as if reacting to the sugar. She told me (...
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What are the differences between mammal and insect digestion of cellulose?

I know that digestion of cellulose is difficult in mammals and requires a lot of steps. But I am fascinated by the idea of one day achieving human digestion of cellulose. Which got me thinking about ...
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Are casein proteins in UHT milk digestable for infants or toddlers?

As a novice cheesemaker, I have read that Ultra High Temperature prosessed milk is unsuitable for cheesemaking, as casein proteins are denatured and cannot be curdled with rennet. I have verified that ...
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23 votes
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Why are sugars in whole fruits not digested the same way sugars in juice are?

In this paper of the WHO, it is claimed that we should limit our consumption of free sugars: WHO recommends a reduced intake of free sugars throughout the lifecourse. [...] Free sugars include ...
Pierre's user avatar
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9 votes
2 answers
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How does the stomach handle continuous eating?

In biology class, we learned this familiar story: Food enters the stomach, the stomach churns it with acid and enzymes, and then, somehow, the stomach senses when the stew is ready and releases it ...
SlowMagic's user avatar
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2 votes
2 answers
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What allows grass eaters to digest cellulose?

Scientists are saying that it was a small step for the Panda to move from a meat diet to a grass diet. The article only refers to differences in the Panda's skull, presumably for better chewing. I've ...
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40 votes
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Why are prions in animal diets not destroyed by the digestive system?

According to CBC: Mad cow disease is the common name for a condition known technically as bovine spongiform encephalopathy, or BSE. [...] The only known source of mad cow disease is from animal-...
Dare to ask-I dnt mind punishm's user avatar
5 votes
2 answers
8k views

Is sugar absorbed into the bloodstream through the walls of the mouth?

If you let a piece of candy melt in your mouth, but did not swallow it, would the sugar be absorbed through the walls of your mouth?
Jeff Wade's user avatar
2 votes
1 answer
152 views

How is fructose absorbed into the body

I’m finding contradicting methods of Fructose transfer to blood page no 264(10)One of which saYs fructose is absorbed by simple diffusion And another sources like this say that fructose is ...
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How much does calcium reduce iron absorption?

Generally calcium inhibits the absorption of iron, but to what extent? One atom of calcium will not block 100% of iron absorption, that clearly isn't feasible. On the other hand, if someone ate 10 ...
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Why are Chloride Anions necessary for gastric acid functioning?

Why do parietal cells of the gastric mucosa release Chloride anions along the H+-ions, which are pumped into the lumen by the proton-pump. Wouldn't the presence of protons alone be enough to denature ...
gregattac's user avatar
15 votes
1 answer
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Do sharks fart?

My son is 5 and I'm encouraging him to be curious and ask questions of the world around him. He asked if sharks fart and how does it smell? He feels that it would smell of fish and be disgusting. He ...
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How does the digestive system determine what to absorb [as nutrients] into the bloodstream?

If you put an egg into a sausage machine it will try to make sausages out of it because that's its job. Does the digestive system attempt to digest everything it receives? Furthermore, does it attempt ...
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21 votes
3 answers
5k views

Why is wombat scat (feces) shaped like cubes?

I've heard that wombat scat is cube shaped, but I don't understand how that can happen. Has anyone studied the phenomenon? What would the evolutionary pressure have been to cause this?
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6 votes
1 answer
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Is gut bacteria Succinivibrionaceae's low methanogenesis understood well enough for GM of cattle gut bacteria to be considered?

After watching the Periodic Table of Videos episode linked in this question I watched the episode Wallabies and Methane where Sir Poliakoff says (a bit after 02:00):...
uhoh's user avatar
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Could a mammal convert ingested dissolved CO2 to usable energy?

I'm trying to find out if it's possible that a mammal could orally ingest dissolved CO2 and convert it to energy for body heat, organ function, etc. Unfortunately, most of the scientific sources I've ...
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Micelles Sticking Together

I have a quick question regarding micelles. I have tried googling the answer but can't seem to find the answer. The question is, during digestion lipids are emulsified into micelles in order to ...
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