r/mildyinteresting • u/atsommers • Aug 17 '26

edible engagement 🍭 One serving from this hydration tube has over 100,000% of your daily recommended vitamin b12

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The package says you can take 1-2 a day lol

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u/VerbalGuinea Aug 17 '26

Is that not accounted for in the USRDA?

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u/AntiqueChessComputr Aug 21 '26

Right? It has to be, or else multivitamins with 100% RDA B12 won’t be nearly enough

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u/Longjumping_Cap_3673 Aug 22 '26

Your body makes a compound called "intrinsic factor" (which is a dumb name). That compound binds to B12 in your stomach, making it easier to absorb later in your intestines. If you eat a lot of B12 all at once, all the intrinsic factor gets used up, and only a small amount of B12 becomes easy to absorb, and only about 1% of the rest is absorbed.

The RDA is based on eating B12 in small amounts throughout the day, so that your body has time to regenerate intrinsic factor in between, but supplements give you a bunch of B12 all at once, so you need much more than the RDA to absorb the same amount. There's no tolerable upper intake (TUI) for B12, and B12 is really cheap to produce, so supplement manufacturers just put a ton of it in B12 supplements to ensure enough is absorbed.

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u/VerbalGuinea Aug 22 '26

Intrinsic Factor sounds like a brand name of a supplement.