Bioavailability stuff is pretty technical and I’m not an expert, but here’s the upshot according to me:
Bioavailability is sometimes slightly lower in plants but not enough to matter. For example, a recent review stated:
There is very little evidence at present regarding a marked difference in protein digestibility in humans. The more precise data collected so far in humans, assessing real (specific) oro-ileal nitrogen digestibility, has shown that the differences in the digestibility between plant and animal protein sources are only a few percent, contrary to historical findings in rats or determinations using less precise methods in humans. For soy protein isolate, pea protein flour or isolate, wheat flour and lupine flour, the figures were 89–92%, similar to those found for eggs (91%) or meat (90–94%), and slightly lower than those reported for milk protein (95%).
Additionally, combining multiple plant sources in one meal (e.g. soy and potato) often achieves bioavailability competitive with meat (I think this is one reason why many vegan protein powders combine multiple ingredients, e.g. rice & pea protein). So the generic vegan advice of “eat a variety of foods and supplement B12” has this covered.
In the rich world, we get way more protein than we need, so vegans are very unlikely to end up protein deficient due to bioavailability issues.
And if you’re an athlete or trying to bulk up, I think it’s generally advisable to err on the side of overshooting your protein intake targets, even if you’re eating meat. Slightly overshooting your protein target should more than compensate for any bioavailability gap.
Ah, today I learned! thanks for correcting that. For what it’s worth I was vegan for two years, and have been vegetarian for 6.
Do you happen to know about the bioavailability claims of animal versus plant protein?
Bioavailability stuff is pretty technical and I’m not an expert, but here’s the upshot according to me:
Bioavailability is sometimes slightly lower in plants but not enough to matter. For example, a recent review stated:
Additionally, combining multiple plant sources in one meal (e.g. soy and potato) often achieves bioavailability competitive with meat (I think this is one reason why many vegan protein powders combine multiple ingredients, e.g. rice & pea protein). So the generic vegan advice of “eat a variety of foods and supplement B12” has this covered.
In the rich world, we get way more protein than we need, so vegans are very unlikely to end up protein deficient due to bioavailability issues.
And if you’re an athlete or trying to bulk up, I think it’s generally advisable to err on the side of overshooting your protein intake targets, even if you’re eating meat. Slightly overshooting your protein target should more than compensate for any bioavailability gap.
We can also measure protein synthesis and muscle strength and mass directly instead of using bioavailability as a proxy, and such studies don’t find downsides to plant protein. Germany’s strongest man can confirm.