Creatinine is a byproduct of creatine phosphate, which is broken down by the body to make energy. You usually test creatinine levels by providing a urine or blood sample. It's an indicator of kidney health. When the body is functioning normally, blood creatinine levels remain normal. However, some conditions or lifestyle choices can cause low creatinine levels. While many causes of low creatinine levels are not harmful, low blood creatinine can sometimes indicate the presence of serious medical conditions.
Low-Protein Diet
Diets that are low in protein can cause low creatinine levels. Foods that are high in creatine phosphate include salmon, pork, tuna and beef, all of which are high in protein. Because these foods are not included in a low-protein diet, there is less creatine phosphate to break down, resulting in reduced creatinine levels.
Pregnancy
Pregnancy may cause low creatinine levels in the blood. Once the fetus starts developing in the womb, nutrients are transported from the mother to the baby via the umbilical cord. Pregnant women may have less creatine phosphate to break down due to the changes in the body. Reduced creatine phosphate breakdown results in reduced levels of creatinine. Once childbirth has occurred, creatinine levels should return to normal unless other causes of low creatinine levels exist.
Decreased Muscle Mass
Creatinine levels are usually higher in men because their muscle mass is higher than that of women. In people who have decreased muscle mass, creatinine levels may be low. Aging causes a natural decline in the amount of muscle mass in the body. Some medical conditions also cause wasting of the muscles and a reduction in muscle mass. Muscular dystrophy and myasthenia gravis are examples of diseases that can cause decreased muscle mass. Disabilities that limit movement can also cause reduced muscle mass due to lack of muscle use.
Liver Disease
Liver disease can contribute to a decline in serum creatinine levels. When liver disease becomes advanced, the organ stops producing as much creatinine. According to Dr. Kevin Pho, who is certified by the American Board of Internal Medicine, liver disease can also result in decreased muscle mass. Diseases that can affect the liver include fatty liver disease, hepatitis and metabolic disorders such as Wilson's disease and hemochromatosis.
