Composting worms as a source of B12 - in SPACE!

[kdorian]

I am working on a fanfic of the Martian, where (among other changes) NASA did not arbitrarily decide to send enough multivitamins to last a single astronaut for four years (the equivalent of sending over 8 months worth per astronaut) when the crew was only due to stay 30 days. He has a decent variety of vegetables to grow for food, and will be

Comments

[alessandriana]

Sorry, but what line in the book suggests he has earthworms? I read it fairly closely for fic purposes recently, and can't for the life of me recall anything about that.

[kdorian]

Sorry, I should have clarified. The mention of worms I'm referring to is not found in the current version, but in earlier versions he refers to them when talking about the decompression of the Hab. "Potatoes are now extinct on Mars. So are earthworms and soil bacteria. I’ll never grow another plant so long I’m here." So far as I know, it's the only time they were ever mentioned.

[alessandriana]

Ah, gotcha. :)

Although I'm not familiar with vermicomposting, this book and this article seem to address some of your question?

[alessandriana]

Looks like my previous comment got marked as spam, so I'll c&p.

From: Significance of vitamin B12 for agriculture, and its natural sources, AGANOVIC, N., Journal: Veterinaria, Sarajevo 1962 Vol. 11 pp. 503-508

"Per 100 g dry matter, earthworms, Eisenia foetida, had from 140 to 260 µg total vitamin B12 and their excreta had from 28 to 127 µg. The stable manure from which the worms were taken had from 16 to 81 µg."

And from "Unity: The Art and Science of Transformational Change" (and I'm not sure how much of a reliable source this is, but it's talking about how vegans can get enough B12): "A possible solution to the B12 issue is to make a probiotic tea from the vermicompost. The worms and actinobacteria help produce 1.5 to 15 mcg per gram of B12 in the vermicast, which is safe to consume." There is more information in the book, which you can pull up through google books-- do a search inside it for 'earthworms b12' and the appropriate page should come up.
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[sashatwen]

No idea about the worms, but I can tell you that unlike many other vitamins, B12 is stored in the human liver. The stores last you for 2-8 years, depending on your prior consumption of animal products and/or vitamin pills. It would probably not be an issue.

[kdorian]

That is very helpful! He's staying for more than two years, but it takes a lot of the urgency out of the situation. I'll start googling about that right now to see if I can figure out how long he would likely have before it became a problem.

[sashatwen]

Glad to be able to help. The number of years is actually dependent on a number of yet unidentified genetic factors as well, that is to say, it varies vastly between individuals. That is why medical literature will only give you a range (I checked pubmed for you before I posted that comment). I would find it absolutely believable if you concluded that his stores would last him for five years or even up to a decade. But do let me know what you turn up.

[lilacsigil]

I was just coming here to say this! People who go vegan often have a health crash about 2 years after the switch when their stored B12 runs out. Then they need to supplement somehow.

[orange_fell]

I googled "do earthworms contain niacin" mistakenly thinking niacin was the same as vitamin B12 (it's not, it's B3), and I found . . . this!

"The earthworms themselves contain between 60-70% protein, 7-10% fat, 8-20% carbohydrate, and 2-3% minerals, and have a gross energy of 4000 kcals ^(-1). In nutritional terms, worm tissue is excellent being equal to meat or fish. It is particularly rich in amino acids, especially lysine, and the vitamins niacin, riboflavin, and vitamin B12, which makes worm tissue valuable as an animal feed."

This is from a book called "The Biology of Wastewater Treatment Plants" which is talking about vermicompost for some reason (I'll be honest, I haven't looked at it much beyond the quoted paragraph). I also found a list comparing relative animal sources of B12, and shrimp (the only invertebrate on it) was said to contain 1.88 mcg of the vitamin per 4 oz, compared to beef with 1.44 mcg / 4 oz, so maybe that's a starting point?

[kdorian]

It helps, thanks!