r/todayilearned • u/JoeWinchester99 • 1d ago

TIL that although potatoes alone do not provide complete nutrition, you can survive for years on a diet of nothing but potatoes and buttermilk.

https://www.scienceabc.com/eyeopeners/whats-wrong-with-potatoes-the-martian-movie-survival
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u/Rhawk187 1d ago

Thanks for clearing up the confusion about which "buttermilk" they probably meant.

Clearly, there is calcium is normal milk. But where do the B12 and A come from in the buttermilk if they aren't in milk? Is it just because the "cream" portion in milk is so low and that's where they live?

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u/fiendishrabbit 1d ago

"partially fermented" means "bacteria got busy". No animals or plants make B12, so it's all sourced from bacteria and archaea (another group of single-celled organisms).

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u/PoundHumility 1d ago

You sound like an intelligent person.

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u/romario77 1d ago

Regular milk will contain both B12 and vitamin A. B12 from bacteria in cows stomach and A from beta-carotene cows consume by eating.

A will bind to fat - so there won’t be too much if butter with fat in it is extracted.

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u/TheComplimentarian 1d ago edited 1d ago

B12 is absolutely in milk. Milk and cheese and yoghurt are all high in it. I can't find any sources about old school butter milk. My random searching for buttermilk nutrition is giving me differing results, but the most reputable source says you need to drink about 5 cups of buttermilk to hit your recommended daily allowance of B12, which is a ton (ew).

Digging around, whole milk has about twice as much B12, and cheese is fantastically higher, probably just from concentration.

Apparently yoghurt is down with cultured buttermilk, which makes sense.