Raw eggs and biotin deficiency?December 7, 2020
There’s a persistent dietary myth claiming that consuming raw eggs causes biotin deficiency.
The perpetuation of this myth likely has more to do with germaphobia or to excuse a distaste for the consistency of raw eggs. That’s ok, you don’t have to like raw eggs, but let’s be clear about the facts of this valuable food preparation (or lack of preparation).
Egg yolks contain more biotin than can be bound by the avidin in raw egg whites. Here are the numbers:
Avidin: 180 µg per egg; molecular weight is 66-69 kDa. Call it 66 kDa for this example. One molecule can bind to 4 biotin molecules.
Biotin: Up to 25 µg per large egg. Call it 10 µg, conservatively, for this example. Molecular weight is 244.31 Da
The amount of biotin bound up by avidin in this example is:
(4 * 180 / 66000) / (10 / 244.31) = 27%
This means the majority of biotin remains freely available for digestion and absorption. Raw eggs are a net positive source of biotin, not a cause of deficiency.
The difference between conventionally farmed eggs and pasture-raised eggs is also worth noting. Imagine how these numbers might play out using eggs from your nutrient-dense backyard chickens/ ducks/ geese/ emu/ quail/ etc. This could mean raw eggs from small local farmers are an even better source of biotin than illustrated here.
Looking for locally produced eggs? Ask your local farmer
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