Q: Does a high protein, low carbohydrate diet contribute to higher levels of creatinine?

A:Creatinine is a breakdown product of creatine, which is an important constituent of muscle. Thus, creatinine is a waste product of muscle or protein metabolism and cannot be used by cells for any constructive purpose. It is excreted from the body entirely by the kidneys and to this end, its level is a reflection of the body’s muscle mass or the amount of protein in the diet. In general, creatinine levels will not vary with a normal diet. However, elevated levels are seen with high protein diets, which may be 10-30% higher in people who eat a diet that is very high in meat. High creatinine levels are sometimes also seen in kidney disease due to the fact that a damaged kidney will not remove creatinine from the body, as it should. Also, elevated levels are seen with the use of some drugs that could impair kidney filtration. Finally, high levels could also be seen with muscle degeneration or a creatine supplementation. Low levels are sometimes seen in kidney damage, protein starvation, liver disease or pregnancy.