Under normal conditions in the body, ammonia, urea, uric acid, and creatinine are produced by protein metabolism and excreted through the kidney as urine. When these by-products cannot be excreted properly from the body they will accumulate and become highly toxic. Protein consumption is a major source of these waste products. An accumulation of these waste products can occur in people with kidney insufficiency who eat a diet rich in protein and therefore can not excrete the waste properly. Blood urea nitrogen (BUN) test measures the amount of urea nitrogen in the blood. Increased levels of urea in the blood (uremia) is an indicator for poor elimination of urea from the body usually due to kidney damage. Increased BUN levels can be caused by kidney diseases, kidney stones, congestive heart failure, fever, and gastrointestinal bleedings. BUN levels can also be elevated in pregnant people and people whose diet consists mainly of protein. Increased creatinine levels in the blood can also be a sign of kidney damage and inability to excrete protein waste by-products properly. A confirmation of kidney disease or kidney failure is often obtained by performing a blood test which measures the concentration of creatinine and urea (blood urea nitrogen). A creatinine blood test and BUN test are usually performed together along with other blood panels for diagnosis.
Protein toxicity
Protein poisoning
Lysinuric protein intolerance
Lipid storage disorder
Metal toxicity
Mitochondrial toxicity
Lead poisoning
Boron deficiency 