Questions tagged [nutrition]

The study of the appropriate provisions required to sustain life in an organism or the provisions themselves.

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49
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11answers
26k views

Can humans survive without consuming life? [closed]

Some people say that it's awful that humans eat animals. They feel that it's barbaric, because you're killing life and then on top of that, you're eating it, and that you should eat vegetation ...
23
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2answers
4k views

Why is it advised that infants are fed mother's milk?

I have heard that mother's milk is preferred over other baby foods, because it contains immunoglobulins (secretory IgA), and other essential nutrients. But why is mother's milk so special? Any ...
23
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1answer
7k views

How can a drink contain 1.8 kcal energy while 0 g fat/carbs/protein?

How is it possible that the Red Bull Zero contains 0 gramms of fat, carbs and protein, but it still has 1.8 kcal of "energy". I always thought that the human body can gain energy only from 3 kinds of ...
18
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5answers
4k views

Has there ever been an attempt to create nutritionally tailored food for adult human consumption?

For all domestic animals, and for all animals kept in laboratory, complete and precise composition of perfect food is figured out (cat food, dog food, cattle, rats, laboratory monkeys and apes) -- ...
18
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1answer
30k views

What is the composition of human feces?

Are there any studies or general information on the composition of human feces? I'd specifically like to know the percentage of carbohydrates and amino acids relative to the amount that was ingested ...
16
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1answer
4k views

Why do humans require vitamin B12 supplementation while herbivores do not?

This question came about from reading the comments of this (very unclear) question, which the author did not properly clarify. Vegans are often recommended to take vitamin B12 supplements, as the ...
16
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2answers
22k views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
15
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2answers
312 views

Relationship between our microbiome and personalized nutrition

Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
15
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3answers
261 views

Spruce growing high up in a maple trunk: Can a partially rotted trunk completely sustain another tree?

I've come across a spruce tree that is growing 15ft up in the crotch of a sugar maple tree: According to Google StreetView, the spruce has been there since before 2007 (over 10 years ago!). I've ...
12
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2answers
400 views

What are the survival limitations of alcohol?

This question was inspired by watching one of the Pirates of the Caribbean movies; particularly where Jack Sparrow allegedly survives on a desert island by finding an unlimited supply of rum. I've ...
11
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2answers
22k views

How do large herbivores get enough protein?

The food they eat seem extremely low on protein. Do they need less protein per mass unit than carnivores? Most of them grow quite a lot in the first year, is most of that from the mothers milk?
10
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2answers
546 views

Do macrophages get nutritional value from the pathogens that they eat?

X-posted on reddit AskScience here. I know that macrophages engulf foreign bodies and transport them to various waste excretion pathways (sorry if the terminology is wrong), and if the foreign bodies ...
10
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1answer
212 views

How does a garlic clove thrive inside a closed refrigerator?

A garlic clove has been growing very well inside a closed refrigerator. It has developed beautiful green stalks, which I think are the equivalent of leafs. Since they are green, I assume they ...
9
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2answers
3k views

Why do carnivores evolve?

If humans can live without consuming other animals, then why do we do it? From a biological point of view, why do we eat meat? I would also extend the question to other animals because many animals ...
8
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3answers
3k views

Where can you find the quantities of each amino acid of a particular protein or food?

Taking a potato as an example. If I wanted to know how much µg or % of each of it's amino acids there are in 1 gram of pure potato protein, where can I find this information? Is there a freely ...
8
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2answers
10k views

What is the distinction between the terms detrivores, decomposers, saprotrophs and saprozoic organisms?

All of them feed on dead and decaying matter (detritus). Detrivores and decomposers are distinct, as it says on Wikipedia, in the fact detrivores consume macroscopic clumps of detritus while ...
8
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1answer
4k views

Is palmitic acid really that dangerous?

According to Wikipedia, "Palmitic acid is the most common saturated fatty acid found in animals, plants and microorganisms. It is also the first fatty acid produced during fatty acid synthesis and is ...
8
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1answer
545 views

Possible to Gain More Weight than the Food You Eat

I was wondering if it's possible to gain more weight than the mass of the food you eat. At a first look, this is impossible because of the principle of mass conservation, but are there other things to ...
8
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1answer
174 views

Do blood glucose “spikes” contribute to insulin resistance, or is prolonged elevation required?

There's increasing public discussion about the health risks of chronic insulin resistance* (IR). In many cases there's a focus on high glycemic index foods that "spike" your blood sugar, which implies ...
8
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2answers
461 views

How was the guided daily amount (GDA) calculated?

We are constantly shown nutritional information on food packaging stating this food contains "x" amount of your guided daily amount. A linked to the values is here. How were these values calculated? ...
7
votes
1answer
2k views

How long do fishes survive in a milk environment?

Suppose you placed a fish, a goldfish for example, into milk instead of water. How long could you expect the fish to survive? Would it die due to lack of oxygen? Is there any other factor that could ...
7
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2answers
1k views

Is cyanocobalamin toxic?

I see that cyanocobalamin is not naturally occurring, and is synthesized in vivo to methylcobalamin. As part of the synthetic pathway, cyanide is broken off. All opinions I can find are that this isn'...
7
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2answers
495 views

Is there a biological reason for spreading food intake into breakfast-lunch-dinner?

I keep hearing over an over how humans can satisfy their entire daily caloric need in one sitting at a fast food restaurant. At the same time I'm looking at the kitchen plates, cups, etc, and they ...
7
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3answers
199 views

Is there evidence to suggest that nutrients in vitamin capsules are not as readily absorbed as the same nutrients in whole foods?

I recently fell ill with a cold, and began to take a vitamin C capsule each day to help my immune system. When I noticed no change in my condition, I began to incorporate an abundance of citrus into ...
7
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2answers
851 views

Can carnivores survive on a (processed) vegetarian diet? Why or why not?

There are many differences in for example the digestive system between carnivores, herbivores and omnivores. It seems that in certain kinds of species adaptability with respect to diet is possible. ...
7
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1answer
419 views

How does a glucose molecule enter the cell from blood vessel?

The transporters in the plasma membrane of the cells promote the entry of glucose molecules from the extracellular matrix to the cytosol of the cell. Could someone explain how does the nutrient ...
7
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1answer
4k views

Powdered meal replacement vs regular meal

Can a person live with this alternative nutrition? Of course, assuming that eating pleasure is assumed the same. The nutrients that contain are far better than average meal a person eats the majority ...
6
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5answers
1k views

Why do the humans become sleepy after meals?

I don't know about all the mankind, but I know enough people, who becomes sleepy after their meals. Also, I'm not sure, what kind of food do they consume, but I personally get sleepy almost from any ...
6
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1answer
13k views

What does the term 'bioavailability' mean?

From what I've read, Bioavailability is the degree to which food nutrients are available for absorption and utilization in the body. How would you explain this with an example?
6
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2answers
582 views

Tap vs. mineral water for drinking

I was told a human should drink a small glass (0,3 liter) of mineral water per day to get the minerals. What is the rationale behind this? What is the difference between tap water and mineral water in ...
6
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3answers
2k views

How is a substance classified as a vitamin?

From wikipedia A vitamin is an organic compound and an essential nutrient that an organism requires in limited amounts. There are many essential nutrients to an organism. Glucose for example. ...
6
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3answers
168 views

laboratory mice, nutrition, and humans

It seems that many nutrition experiments [directed at human diet] are carried on laboratory mice. Is there any justification that nutrition that is good or bad for laboratory mice will also be same ...
6
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1answer
1k views

Do plants have preference for the form of nitrogen as nutrient?

In the nitrogen cycle (ecology), it is usually described that plants can use nitrogen in the form of ammonium (NH4+) and nitrate (NO3-). Do plants prefer one form of nitrogen over the other?
6
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1answer
73 views

Why are plants unable to take up Phosphorus directly in their organic form like Phytic Acid?

I am researching acquisition strategies of phosphorus by decidious trees. I am reading a lot that plants take up nutrients as their inorganic form. In the case of P according to literature this is ...
6
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2answers
242 views

Do omnivore mammals vary food preferences based on dietary needs?

I'm wandering if mammals that can eat many different kinds of food (omnivores) vary their preference for food not only based on the availability, but also based on dietary needs? I'm looking at this ...
6
votes
1answer
254 views

functional hypocholesterolemia due to very high HDL or low LDL?

Nutritional and medical recommendations about cholesterol seem to focus exclusively on hypercholesterolemia, and as such, they provide only a maximum desirable level for LDL and a minimum for HDL. I'...
5
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2answers
113 views

What vitamins exist for other animals but not humans?

As you probably know, humans are among the minority of animals that require Vitamin C and don't produce it ourselves. For whatever reason (multiple theories exist), we lost the ability. Meanwhile, the ...
5
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1answer
2k views

What are 'acid stable' amino acids?

I tend to see terms amino acid, acid stable amino acid, and free amino acids used often in ...
5
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5answers
3k views

Why can't you just take a vitamin? Why you need a healthy diet on top of that?

From what I understand, your body needs certain amounts of vitamins and minerals to maintain health. Why can't we just take enough pills to obtain these vitamins and minerals?
5
votes
1answer
462 views

Mites on ginger root

I was just looking at some mouldy ginger found in the fridge under the microscope and was horrified/delighted to find (what looked to be) mites growing in it. I have searched the web and can only find ...
5
votes
1answer
361 views

What are minerals (other than zinc) that the human body cannot store

It is known that zinc is an essential mineral that the body cannot store. What are other minerals, especially metals, that the body cannot store? (other than water-soluble vitamins such as vitamin B ...
5
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1answer
87 views

Enzymes and Digestion

If biological enzymes (protease,amylase,lipase etc.) just speed up the reaction (in the digestion process), then what actually digests the food?? (I'm a secondary student)
5
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2answers
19k views

Which are mobile and immobile elements in plants?

I am confused with this element or nutrient classification in the plants, since some authors set elements like $\ce{S}$ and $\ce{Ni}$ as mobile and other as immobile elements (Citation 1, 2, 3, 4, 5). ...
5
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1answer
857 views

Fats as energy source

As we know that the preferred source of energy for our body (source) are carbohydrates but heart muscle is an exception and need some explanation for this exception, that why the preferred source of ...
5
votes
1answer
77 views

Vitamin and mineral contents of common fruits

I'm looking for nutritional data, mostly vitamin and mineral contents of common fruits, such as apples, bananas, oranges, kiwis etc. Are there scientific (published and peer-reviewed) sources that ...
4
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2answers
3k views

How do roots obtain nutrition?

I have a city garden (see picture below) and yesterday I was nurturing it and I pulled up a small plant. I saw its root system and laid it in the sun to dry a bit and then scraped of the rest of the ...
4
votes
2answers
172 views

Why are dietary recommendations for methionine consumption combined with cysteine?

I want to understand the amino acids missing in certain vegetables. I looked up the US recommendations for amino acids (source: wikipedia). I don’t understand why they pair Methionine + Cysteine: ...
4
votes
1answer
211 views

In theory, would it be possible to create an injection of Vitamins, Minerals, sugars etc so that eating was no longer necessary?

I am wondering, out of pure curiosity, whether with current medical & biological science, (or indeed with accepted probable future developments in those areas), in theory, would it be possible to ...
4
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1answer
2k views

Nutrient limitation in terrestrial and freshwater ecosystems

In terms of primary production, it is often described in textbooks that nitrogen is the most limiting nutrient in terrestrial ecosystems, while phosphorus is the most limiting nutrient in freshwater ...
4
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2answers
1k views

Do we know a complete list of nutrients that humans must ingest to live?

When the people who are making "nutritionally complete" foods like Soylent are developing their product, how do they know that they've covered all their bases? You need to have protein, carbohydrates, ...