nitrogen balance, the relationship between the amount of nitrogen taken into the body, usually as food, and that excreted from the body in urine and feces. Most of the body’s nitrogen is incorporated into protein. Positive nitrogen balance, which occurs when the intake of nitrogen is greater than its excretion, implies tissue formation and growth. Negative nitrogen balance, which occurs when more nitrogen is excreted than is taken in, indicates wasting or destruction of tissue.
