Final answer:
The kidneys can be damaged by excessive protein intake due to the added strain of filtering byproducts, potentially leading to conditions such as nephrotic syndrome or diabetic nephropathy. The liver can also be affected by substances like copper causing hepatic cirrhosis and renal tubular damage.
Step-by-step explanation:
The organ that may be damaged by excessive protein intake is the kidney. Proteins are usually not filtered out in the glomeruli, but when there is damage to the glomerular capillaries, proteins such as albumin can leak into the urine, indicating conditions like nephrotic syndrome or diabetic nephropathy. Consuming too much protein over time can strain the kidneys since they have to work harder to eliminate the byproducts of protein metabolism. It's also worth noting that the liver can be affected by excessive deposition of certain substances like copper, which can cause hepatic cirrhosis and renal tubular damage.