According to conventional wisdom, patients with kidney disease must consume a low-protein diet.

With their recent study on the relationship between protein intake and skeletal muscle mass in kidney transplant recipients, scientists from Osaka Metropolitan University demonstrated that this may not always be the case. Clinical Nutrition published their findings.

Chronic kidney disease patients have been shown to have induced sarcopenia as a result of chronic inflammation, hypercatabolism, decreased nutrient intake and decreased physical activity, all of which are associated with impaired kidney function.

Many of these physiological and metabolic abnormalities can be corrected or improved as a result of successful kidney transplantation.

As a result, kidney transplant recipients gain skeletal muscle mass after receiving a kidney transplant. Because too much protein impairs kidney function, it's widely assumed that patients with chronic kidney disease, including kidney transplant recipients, should limit their protein intake to protect their kidneys.

Severe protein restriction, on the other hand, has been linked to worsening sarcopenia and a poor prognosis. Protein intake is thought to be related to the recovery of skeletal muscle mass after kidney transplantation because nutrition and exercise therapy are recommended to improve sarcopenia. Few studies, however, have looked at the link between skeletal muscle mass and protein intake in kidney transplant recipients.

To fill this void, a research team led by Dr. Akihiro Kosoku, Dr. Tomoaki Iwai, and Professor Junji Uchida at the Department of Urology, Graduate School of Medicine, Osaka Metropolitan University investigated the relationship between changes in skeletal muscle mass (as measured by bioelectrical impedance analysis) and protein intake (as estimated from urine collected from 64 kidney transplant recipients 12 months after transplantation).

The findings revealed that changes in skeletal muscle mass during this time period were positively correlated with protein intake, and that a lack of protein resulted in a loss of muscle mass.

Dr. Iwai and Dr. Kosoku stated, "Further research is needed to clarify the optimal protein intake to prevent either deterioration in kidney function or sarcopenia in kidney transplant recipients." We hope that nutritional counselling, including protein intake, will improve life expectancy and prognosis."