Hi Deuce12345,
Good question.
Sounds like you and the doctor are still investigating the situation. If the issue is allergy or autoimmune related, then typical diet recommendations from us may not suffice and would need to come from a doctor or dietician.
Having said that, to answer your question directly:
- Yes, plant based protein supplements like pea, rice and hemp exist. Particularly, blends (eg: pea + rice) may be a good option since they provide complete amino acid profiles as a result.
- Perhaps you are (or maybe are *now*) allergic to dairy. Many people are (even with low-lactose forms of whey protein) and don't realize it. Try eliminating it for a period.
- Not to go down a rabbit hole, but there are concerns--as you can of course argue it applies to almost any food--around the "other" contents of plant proteins like pea and especially rice due to the places in the world from which they're sourced, the use of pesticides and also the nature of the plant themselves. This includes higher levels of heavy metal such as arsenic.
I know this isn't what you're asking, but to answer it from a different angle:
- To shamelessly quote Stan Efferding: "Shakes are for fakes". (I'm only saying it to add color to what I'm saying. Don't take it personally

). I train in powerlifting and bodybuilding, and do not use any powders. I certainly have at some point, but the benefits and reliance on them are massively exaggerated. The only supplements I take are vitamin D and fish oil. You absolutely do not need powders/shakes. I don't know why people insist on the necessity and nearly supernatural benefit of protein powders (and other supps). I'm not going to go into the cons (or even pros) of these products.
- What I'm saying is just eat real food. Eggs (yes, this is the topic of discussion, so maybe avoid), chicken and of course BEEF. Steak is an amazing source. That is, unless, you're vegetarian. I used to be, btw.
- I also suggest not being too concerned about what you were referring to with regard to bioavailability. Yes, whey protein and eggs are the most bioavailable forms (though one is processed and one is natural), but it's not like if you eliminate whey protein, but include other healthy sources of protein you'll suddenly disintegrate.
This is no criticism to you and I don't know your complete lifestyle, but people like us tend to live by a regimen, in this case related to diet, which looks like: Wake, oatmeal, egg, train, protein shake, chicken breast, broccoli, sleep. Repeat. (Not necessarily accurate, but you get it )
Break up the monotony for your body.
Finally, if you do switch to a different protein powder source, keep in mind the alteration in your macros. You'll need to be mindful of the new lack/reduction of fats.
Hope you didn't mind the long-winded answer.
I really hope you identify the issue and it's simply and allergy or easy food to remove from your diet!