Probably. It’s easier for kidneys to process proteins from vegetable sources like soy, lentils, beans, corn and the like than to process animal proteins, said Dr. Theodore Steinman, a kidney specialist and senior physician at Beth Israel Deaconess Medical Center in Boston.
When you eat protein, you absorb the amino acids from the protein, and excrete excess sodium, potassium and other substances the body doesn’t need. If the kidney didn’t get rid of these wastes, said Steinman, the byproducts of protein metabolism would build up to the point of toxicity, as occurs with kidney failure.
Compared to vegetable protein, animal protein generally has more salt and potassium and produces much more acid. To keep the body chemistry in the correct acid balance, the kidneys must pair each acid molecule with a base to neutralize the acid. “That’s a lot of metabolic work for the kidney,” said Steinman.
Vegetable proteins contain much less acid, “so the metabolic work by the kidney is much less,” said Steinman.
Dr. David Heber, director of the Center for Human Nutrition at UCLA, agreed. Some studies suggest that when animal proteins are metabolized by the kidneys, there is increased blood flow to the kidneys which theoretically may be linked to increased risk of kidney disease. By contrast, vegetable proteins do not increase blood flow to the kidneys, so are presumed to be safer.
Bottom line? “If we were smart, we would all be vegetarians,” said Steinman, who concedes that he eats mostly vegetables but “can’t give up my love for fish, and sometimes chicken.”