Hi, Nanda, and welcome to the forum. Do you, or someone you know, have liver disease? Regarding protein, red meat is the most difficult protein for the liver to digest, so it's recommended that those with liver disease refrain from eating it. Soy protein can be found in powder form and mixed with milk or juice, or you can get soy beans frozen and shelled and use it in stirfrys. It also comes roasted as soy nuts. There are many soy-based products, but read labels and beware of sodium. Seafood is also a good choice for protein, or skinned chicken breast.
I personally didn't have any positive effects from milk thistle. Some do. It won't hurt, but may not help.
For additional information, you should consult a hepatologist or a nutritionist who works with liver patients.