Which of the following best describes the relationship between urea and protein intake?

The relationship between urea and protein intake is most accurately described by the understanding that higher protein consumption leads to increased urea production. When dietary protein is consumed, it is ultimately broken down into amino acids. These amino acids undergo deamination, a process in which the amino group is removed, producing ammonia as a byproduct. The liver then converts this ammonia into urea, which is less toxic and can be safely excreted from the body through urine. As the intake of protein increases, so does the amount of amino acids available for deamination, thereby leading to a corresponding increase in urea production as the body works to eliminate the byproducts of protein metabolism.

This mechanism illustrates the body's method of maintaining nitrogen balance, with urea serving as a key indicator of protein metabolism. Higher protein intake thus directly correlates with increased urea levels in the bloodstream, making it a reliable marker for assessing protein intake and turnover in the body.