Naked Science Forum
General Science => Question of the Week => Topic started by: katieHaylor on 21/05/2018 14:45:50
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Eamonn asks:
If some day we managed to travel to another planet, and discovered aliens, what is the likelihood that we could eat them?
What do you think?
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Surely you meant could we "E.T." an alien?
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That depends on how similar we are to them. They would need to be sufficiently similar to us biochemically in order for our enzymes to break down whatever their tissues are made of. Even being carbon-based wouldn't be enough of a guarantee. They might, for example, be composed of molecules that are the chiral mirror of our own. Our enzymes would have trouble with those.
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They might, for example, be composed of molecules that are the chiral mirror of our own. Our enzymes would have trouble with those.
That's a good point, although the stomach acid should do a reasonable job of hydrolysing the bonds and releasing individual more-digestible components.
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stomach acid should do a reasonable job of hydrolysing the bonds and releasing individual more-digestible components
Your stomach acid can break down proteins into individual peptides (amino acids).
But only the simplest amino acid (glycine) would be equally delicious to both L & D based lifeforms.
The others are all chiral at the level of individual amino acid units.
It's hard to test the effects of opposite chirality due to the difficulty of generating nutrients with opposite chirality.
We do know that some molecules with antibiotic properties contain amino acids units of opposite chirality, which really upsets bacteria ingesting them.
I suspect that at a minimum, you would suffer severe malnutrition, as you probably can't live off just glycine for your protein input.
https://en.wikipedia.org/wiki/Amino_acid#Isomerism
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If some day we managed to travel to another planet, and discovered aliens, what is the likelihood that we could eat them?
Probably about the same chance that they could eat us...
Of course we may do a lot of damage to each other without actually being mutually nutritious or mutally non-poisonous...
Other factors, if you move outside "life as we know it":
- Temperature: You would suffer severe burns trying to eat anything living on Venus, and severe frostbite trying to eat anything from Titan.
- Pressure: Some imaginary gasbag lifeform living at high pressures deep in the atmosphere of Jupiter or Saturn would explode if you bit into it. Something living on the airless surface of Ganymede would implode if you brought it into normal Earth pressure.
- Chemistry: Lifeforms based on silicon, or built around a non-polar liquid ethane/methane solvent would not be compatible with our digestive system or nutritional needs.
- More: An imaginary magnetic/plasma creature living in the Sun would cause severe injury even getting close...
I suspect that most of us would have trouble recognising non-technological aliens on any planet we visited - I think it would require specialists who are prepared to "think outside the (lunch)box".
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It's not absolutely clear that we would even recognise an "alien".
However, I'm reminded of the old joke- all mushrooms are edible; once.
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This topic has now been answered!
Listen to the podcast here:
https://www.thenakedscientists.com/podcasts/question-week/could-we-eat-alien-life
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I would point out the difference between putting stuff into the stomach, and getting nutrition from that stuff.
I'm sure we could munch on an extraterrestrial, and hope its flesh is made of proteins built of amino acids similar to our own, and of carbohydrates and fatty acids compatible to our digestive processes.
Digesting an alien could be left up to the extraterrestrial bacteria, much as a grazing animal leaves the job of digesting grasses to the microbes, which in turn nourish the bovine.
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Eamonn asks:
If some day we managed to travel to another planet, and discovered aliens, what is the likelihood that we could eat them?
What do you think?
People have already mentioned Molecular Chirality & noted that most of earth's organisms use (& can only process with Enzymes) Left (L) Handed chirality. I did want to mention that Right (R) Handed molecules do show up occasionally, they just can't be properly processed by our Left Handed Enzymes. Also, R molecules taste sweet to our taste buds, so R-based Alien life forms could be tasty, just indigestible.
The aspect of Alien Life that hasn't been mentioned yet is the probability that it could trigger an Immune Response & even Anaphylaxis. Even a single bite could cause your immune system to go on the warpath, attacking everything in sight - eventually causing your lungs to fill with fluid & your throat to swell closed, quickly killing you.
The Color of Distance by Amy Thompson is a science fiction novel that addresses some of the difficulties of visiting alien worlds. In the book, humans must live in completely sealed off from the xenobiology, as the slightest contact with any of the local environment will trigger an intense immune response (Anaphylaxis) that would potentially be lethal.
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How would we have an immunoglobulin E that reacts to an alien we have never encountered before?
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How would we have an immunoglobulin E that reacts to an alien we have never encountered before?
Your body produces vast numbers of antibodies with subtle variations in their binding structures generated through a mechanism called Somatic Hypermutation - including many that react to no known analog in nature (at least on this planet).
As well, there's more than one pro-inflammatory pathway that can trigger the excess of Histamine required for a lethal reaction - though most are perceptibly slower.
Perhaps by an anomalous Cytokine response triggered by alien proteins that were (by a mathematically improbable coincidence) similar to those of an earth parasite? You'd only have to inhale a couple of pollen spores for an immune response to begin, so naturally consuming a portion of some xenofood would make it much worse as you'd have lots more proteins to react to & only emesis to remove them from your stomach (not to mention the damage to your intestinal flora, which you need to absorb several essential nutrients).
It might not be as spectacular as the Type 1 Hypersensitivity that someone allergic to peanuts would experience on eating some peanut butter, but the end result would be just as unpleasant, and deadly.
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Could be...
But it's a lot more likely that we would just get an upset stomach.
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Re: QotW - 18.05.21 - Could we eat an alien?
" To Eat or Not to Eat " , that should be the Question.
P.S. - Should We ? 🐒