I was looking for extracts - supplements for my kidneys to improve them - and found that Agaricus bisporus is sometimes called Portobello mushroom - it is a strain of the same fungus as button mushroom.
This knowledge makes it so much easier to find the Agaricus bisporus - because you can find Portobello mushrooms at the grocery store.
You will want to start eating the Portobello mushroom 1/4 of a whole one at first - to see how you can handle it if you are a little weak. I eat 1/2 of one a day - but eventually I hope to eat a whole one. You don't have to cook it - you can eat it raw.
I never knew this information on the Agaricus bisporus/Portobello mushrooms.
I hope this will help end-stage kidney people! I am one.