Monoamine oxidase (MAO) inhibitors. Meat “tenderized” with papaya or a papain powder
can interact with the class of antidepressant drugs known as monoamine oxidase inhibitors.
Papain meat tenderizers work by breaking up the long chains of protein molecules. One
by-product of this process is tyramine, a substance that constructs blood vessels and raises
blood pressure. MAO inhibitors inactivate naturally occurring enzymes in your body that
metabolize tyramine. If you eat a food such as papain-tenderized meat which is high in tyra-
mine while you are taking an MAO inhibitor, you cannot effectively eliminate the tyramine
from your body. The result may be a hypertensive crisis.
Veal