What is a common cause of elevated blood urea nitrogen (BUN)?

Elevated blood urea nitrogen (BUN) levels are commonly associated with high protein intake. When a person consumes a significant amount of protein, the body breaks it down into amino acids, which are then metabolized. The byproduct of this protein metabolism is urea, a nitrogen-containing substance that is formed in the liver and then excreted by the kidneys. As protein intake increases, more urea is produced, leading to an increase in BUN levels in the blood.

While hydration level can influence BUN readings, particularly in cases of dehydration where BUN can appear elevated due to concentration effects, it does not directly cause an increase in the production of urea itself. Glucose imbalance and electrolyte imbalances do not typically influence BUN levels in a direct manner related to the metabolism of proteins. Thus, the link between high protein intake and elevated BUN is a well-established physiological response.