Wikipedia:Reference desk/Archives/Science/2017 October 27

= October 27 =

Zero living diet
Are there any foods that have never lived? Meaning, no animals, plants bacteria etc. Would it be possible to live on such diet? --


 * Water... most people might last a few weeks. Roger (Dodger67) (talk) 06:18, 27 October 2017 (UTC)


 * Only prokaryotes can do that, they have the enzymes to take in abiotic chemical compounds and make all the stuff they need. Eukaryotes are dependent on other organisms for their survival, e.g. they can't make vitamin B12, they don't have the enzymes for nitrogen fixation either, so they are dependent on prokaryotes for their amino-acids. Count Iblis (talk) 06:32, 27 October 2017 (UTC)


 * It is possible to make synthetic fatty acids - mercifully, it doesn't seem to have caught on; I guess the odd-numbered ones did not even meet up to the standards of the trans fat era.  Synthetic sugars are harder.   Vitamin supplements are an issue, yet some are produced synthetically.  There is no theoretical reason why such a diet cannot be produced (though you might need to go off-planet to find carbon you are somewhat confident 'never lived'), but it would be exceedingly difficult, so I would not expect the first test subjects to live long.  Also note that ethane, present on Titan, is metabolized by the rat  so at least some "foods" presently exist that match this criterion, though it would be poorly nutritious and a bit over-chilled on the palate. Wnt (talk) 11:03, 27 October 2017 (UTC)


 * There are many kinds of extremophiles that live on, for example, organic chemicals that seep into the oceans from mid-oceanic hydrothermal vents. Chemosynthesis would be the term.  As to the main question, no, it is not possible for you as a person to live on food which has never lived.  Excepting certain dietary minerals, which do not provide energy to your body, food entails life.  All food must have been living at some time previous, for any reasonable definition of "previous".  Some foods are currently living.  Indeed, many raw plant foods we eat are alive while we consume them.  -- Jayron 32 11:06, 27 October 2017 (UTC)
 * Can we say that plants have a diet of non-living food? I mean they just need water and minerals from the ground, CO2 in the atmosphere, and sunlight for energy. I guess the question is more about whether you accept that plants "eat" at all. — Preceding unsigned comment added by Lgriot (talk • contribs)
 * Well, that's it. We need to define "eating".  I mean, I would define that as ingesting a substance for the purpose of obtaining energy and building materials.  There are other forms of ingesting we do (drinking, smoking, taking medicine or vitamins) which we don't call eating.  Wikipedia's article on eating specifically excludes most plants, since plants are autotrophs.  If you change the definition of eating, then sure, you can define plants as eating.  But really, if you can just change the definitions of words to fit your needs, you can "prove" anything with those words.  -- Jayron 32 14:42, 27 October 2017 (UTC)
 * Note that plants depend on bacteria to do the nitrogen fixation necessary to make amino acids. Count Iblis (talk) 18:00, 27 October 2017 (UTC)


 * The answers to a similar question from 2014, Reference_desk/Archives/Humanities/2014_August_14, may be of interest.--Wikimedes (talk) 18:39, 27 October 2017 (UTC)


 * There aren't any foods currently consumed that have never lived, but it would be possible in principle in make some. Probably the easiest, as far as I can tell, is ethanol -- which in spite of its use as an intoxicant is actually a high-calorie food source.  Other edible foods can be made by artificial photosynthesis or chemical synthesis, for example simple sugars such as glucose, but the process is very expensive. Looie496 (talk) 21:14, 27 October 2017 (UTC)


 * @ Looie496 What about milk and honey? 185.217.68.208 (talk) 07:14, 30 October 2017 (UTC)


 * There are many minerals which, by definition, are produced by inorganic processes. Sodium, iron, calcium, potassium, etc. These are essential parts of the diet, but obviously not sufficient alone.  Of course, just like with carbon, they may have been part of a living organism at some point in the past. StuRat (talk) 22:50, 27 October 2017 (UTC)


 * The relevant article is abiogenesis. Even if you hold the fringe panspermia theory, the first life to arise (or "arrive") here on Earth was, pretty much by definition, bathed in a sea of free, simple organic nutrients.  Last universal common ancestor describes an organism that derived its energy using chemiosmosis, but this organism would have been quite a bit more sophisticated than the first living protocell. μηδείς (talk) 18:31, 29 October 2017 (UTC)


 * See chemoautotrophy. There are archea at deep ocean vents that "eat" only inorganic chemicals that come out of the earth. This is not "food" for you or me, but it is for them, and is probably the only known thing that roughly counts as an answer to your question. SemanticMantis (talk) 18:52, 29 October 2017 (UTC)


 * I think hydrothermal vent nutrients may not be seeing the biosphere for the first time. My impression of the biogeochemistry of volcanism is that often magma is released relatively rapidly from descending subduction zone material.  I would not, however, be ready to guarantee that is always true. Wnt (talk) 02:23, 31 October 2017 (UTC)