12

The estimated daily requirement needed to maintain body stores of B12 varies, an estimate being from 2µg to 5µg, more if stores have been depleted in any way. It is estimated that the average person stores about 1 mg (1000 µg) of B12 in their liver, and other smaller amounts elsewhere. The recommended daily allowance assumes a 50% absorption rate of ingested ...


4

No. There have been several trials testing this and they have not shown benefit. One example of the conclusion from such a trial: Supplementation with vitamins C and E during pregnancy does not reduce the risk of preeclampsia in nulliparous women, the risk of intrauterine growth restriction, or the risk of death or other serious outcomes in their ...


2

Let me address this point mentioned in the question: "My apothecary person told me 500-1000 µg per day are needed to even start absorbing meaningful quantities by ingestion." This addresses a problem with the way we absorb vitamin B12. As explained here, when vitamin B12 is ingested, certain so-called transport proteins are needed to move it to the ...


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