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  • Writer's pictureCheryl Young

The Role of Kidneys in Protein Processing for Muscle Building - Implications for Health and Fitness

When it comes to building muscle and improving our health and fitness, protein is a key nutrient. While many of us focus on factors such as exercise and nutrition, we often overlook the vital role our kidneys play in this process. The kidneys are responsible for processing protein and removing waste products, ensuring optimal muscle development. However, impaired kidney function and having only one kidney can pose challenges and potential risks when striving to build muscle. In this article, we will explore how kidneys process protein, the impact of impaired kidney function on muscle building, and the considerations individuals with one kidney should keep in mind.

The Kidneys' Role in Protein Processing:

The kidneys serve as essential organs in maintaining overall health, including muscle development. Their primary functions related to protein metabolism are:

1. Filtration: The kidneys filter blood, removing waste products and excess substances, including nitrogenous waste generated from protein metabolism (Shemesh et al., 2018).

2. Reabsorption: After filtration, the kidneys selectively reabsorb necessary nutrients, including amino acids, to maintain a balance within the body (Wang et al., 2020).

3. Regulation of Nitrogen Balance: The kidneys play a critical role in regulating nitrogen balance by excreting nitrogenous waste products, such as urea, while preserving essential amino acids for bodily functions (Walrand et al., 2018).

4. Gluconeogenesis: In conditions of limited glucose availability, the kidneys can convert amino acids obtained from protein into glucose to provide energy for the body (Moorthi et al., 2021).

Impaired Kidney Function and Muscle Building:

Impaired kidney function can significantly impact the muscle-building process. When kidneys are compromised, they may struggle to effectively process protein and eliminate waste products, leading to various complications:

1. Reduced Protein Metabolism: Impaired kidney function can limit the ability to efficiently metabolize protein, affecting the body's ability to synthesize and repair muscle tissue (Kopple, 2019).

2. Increased Protein Catabolism: Kidney dysfunction may lead to increased protein breakdown and the release of amino acids from muscles, hindering muscle growth and recovery (Carrero et al., 2020).

3. Electrolyte Imbalance: Kidney impairment can disrupt the balance of electrolytes, such as sodium, potassium, and calcium, which are crucial for proper muscle function and contraction (Walrand et al., 2018).

Building Muscle with One Kidney:

Individuals with only one kidney face unique considerations when it comes to muscle building. While it is possible to build muscle with a single kidney, it is essential to prioritize the health and function of the remaining kidney:

1. Adequate Hydration: Maintaining proper hydration is crucial for kidney health and optimal muscle function. Sufficient water intake helps support kidney filtration and prevent dehydration-related complications (Roncal-Jimenez et al., 2019).

2. Balanced Protein Intake: Individuals with one kidney should ensure they consume an appropriate amount of protein to support muscle building and repair. Consulting a healthcare professional or registered dietitian can help determine the ideal protein intake based on individual needs and kidney function (Dolan et al., 2020).

3. Monitoring Creatinine Levels: Regular monitoring of creatinine levels, a waste product excreted by the kidneys, can provide insight into kidney function. Consulting a healthcare professional for regular check-ups and blood tests is important to ensure kidney health (National Kidney Foundation, 2021).

Protein processing by the kidneys plays a crucial role in muscle building and overall health. Impaired kidney function can hinder muscle development and recovery, emphasizing the importance of maintaining optimal kidney health. Individuals with one kidney should be mindful of their protein intake, hydration levels, and regular monitoring to support muscle building while safeguarding their kidney health. Consulting healthcare professionals can provide personalized guidance based on individual circumstances, ensuring a safe and effective approach to building muscle and improving fitness.

It’s crucial to be mindful of our key organs to help keep them functioning optimally, for as long as we possibly can - pharmaceutical free. Our health and longevity depends on it.


• Carrero, J.J., Stenvinkel, P., & Cuppari, L. (2020). Role of Muscle in the Disposal of Endogenous and Exogenous Nutrients. In Handbook of Nutrition and Diet in Dialysis (3rd ed., pp. 269-278). Springer.

• Dolan, E., Varley, I., Ackerman, K.E., Pereira, R., Elliott-Sale, K.J., Sale, C., ... & Grgic, J. (2020). The Bone Metabolic Response to Exercise and Nutrition. In International Association of Athletics Federations Consensus Statement (pp. 1-46). Sports Medicine.

• Kopple, J.D. (2019). Nutrition and Metabolism in Renal Disease. In Comprehensive Clinical Nephrology (6th ed., pp. 551-570). Elsevier.

• Moorthi, R.N., Avin, K.G., & Martin, B.R. (2021). Bone and Muscle Interactions: Impact on Whole Body Metabolism. In Endocrine Physiology (4th ed., pp. 629-652). Elsevier.

• National Kidney Foundation. (2021). One Kidney or a Kidney Transplant. Retrieved from

• Roncal-Jimenez, C., Lanaspa, M.A., & Johnson, R.J. (2019). Kidney, Muscle, and Hydration. In Handbook of Clinical Nutrition and Stroke (2nd ed., pp. 131-139). Humana Press.

• Shemesh, O., Golbetz, H., Kriss, J.P., & Myers, B.D. (2018). Limitations of creatinine as a filtration marker in glomerulopathic patients. Kidney International, 28(5), 830-838.

• Wang, W., Guan, Q., & Chen, S. (2020). Renal Metabolism in Chronic Kidney Disease. In Pathophysiology of Renal Disease (pp. 75-92). Academic Press.

• Walrand, S., Gryson, C., Salles, J., Giraudet, C., & Migné, C. (2018). Role of Protein and Amino Acids in Muscle Health and Protein Requirements in Older Women. Nutrients, 10(3), 360.

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