wasProtein is known as the building block of life. It is essential for muscle repair, growth, hormone regulation, and maintaining healthy skin, hair, and nails. However, a common concern among people who consume high-protein diets is whether high protein cause kidney damage.
Does High Protein Cause Kidney Damage Summary
- The study compared the effects of two different protein intakes (1.6 g/kg or .8 grams per pound and 3.2 g/kg/day or 1.4 grams per pound) during 16 weeks of either resistance or concurrent training on body composition, strength, and performance in resistance-trained males.
- The study found that a daily protein intake of 1.6 g/kg or .8 gram per pound is generally sufficient for maximizing gains in lean mass, muscle strength, and performance in resistance-trained males, irrespective of whether they are engaged in resistance training (RT) or concurrent training (CT).
- The only exception was peak power, where the group with a higher protein intake of 3.2 g/kg/day or 1.4 grams per pound showed greater gains than the other groups.
- The study found that both resistance and concurrent training combined with high protein intake led to significant improvements in body composition, strength, and performance, with no adverse effects on liver and kidney function.
Nutrition and Kidney Health
The high-protein diet has been debated for years, especially among athletes who consume large amounts of protein to enhance muscle growth and recovery. One of the most common misconceptions is high protein cause kidney damage. However, recent research has challenged this belief, suggesting that high protein intake does not harm kidney function in healthy individuals.(Bagheri et al., 2023) This article reviews the available evidence and studies supporting that high-protein diets do not cause kidney damage, particularly in athletes who consume high amounts of protein.
Evidence Supporting the Safety of High-Protein Diets in Athletes:
It is well known that athletes consume a higher-than-normal protein diet to support muscle mass and reduce body fat. A study to evaluate the protein requirements of trained strength athletes. The results indicated that protein requirements for athletes performing strength training are higher than those for sedentary individuals and exceed the recommended daily protein intake requirements.
Does Protein Damage the Kidneys
These findings suggest that athletes can consume higher amounts of protein without compromising kidney function. The results revealed that even high protein intakes of 2.40 g protein/kg/day or 1.1 grams per pound did not negatively impact kidney function in healthy athletes.(Tarnopolsky et al., 1992; Tipton, 2011)
The Common Misconception: Does High Protein Damage Kidn
The idea that high protein cause kidney damage has been around for years. This notion is often supported by studies that show a connection between high-protein diets and chronic kidney disease (CKD). (Ko et al., 2017) However, it’s essential to note that most of these studies focus on individuals with pre-existing kidney conditions. The general public often misinterprets these findings, spreading fear and misinformation about high protein cause kidney damage.
The Science Behind Protein and Kidney Function
Protein metabolism produces waste products like urea, which the kidneys filter. The argument is that a high-protein diet increases the kidneys’ workload, potentially leading to kidney damage over time. (Martin et al., 2005) However, this simplified view doesn’t consider the kidneys’ adaptability and the absence of evidence linking high protein intake to kidney damage in healthy individuals.
Some have suggested this is a normal adaptive mechanism in response to various physiological conditions. (Martin et al., 2013) Likewise, a panel charged with establishing reference nutrient values for Australia and New Zealand also stated there was no published evidence that elevated protein intakes negatively impacted kidney function in athletes or in general.(Brändle et al., 1996)
Studies Supporting High-Protein Diets: Debunking the Myth that High Protein Cause Kidney Damage
Martin et al. (2013) conducted a comprehensive review of available evidence and found no significant evidence for the detrimental effect of high protein intake on kidney function in healthy individuals. They argue that the human body has adapted to a high-protein Western diet over centuries, indicating that high protein intake is not inherently harmful to kidney health.
One study investigated the renal consequences of high protein intake in well-trained athletes and found that protein intake below 2.8 g/kg or 1.27 grams per pound did not impair renal function. The study measured renal creatinine, urea, and albumin clearances within the normal range. (Dellalieux, 2000)
New Study: High-Protein Diets and Athletes: No Evidence of Kidney Damage
Athletes often consume high-protein diets to support muscle growth and recovery. A recent study found that neither a 1.6 g/kg nor a 3.2 g/kg high-protein diet affected liver or kidney function in resistance-trained males.
Study Design
The study design involved recruiting 48 young, healthy, resistance-trained males aged between 18 and 36 years. It was 16 weeks, and various performance metrics were assessed pre-, mid-, and post-intervention. The subject were randomly assigned to one of four groups:
- Concurrent training, which involves both resistance and endurance training +1.6 g.kg per day of protein (CT1),
- CT +3.2 g.kg per day of protein (CT2),
- Resistance exercise only +1.6 g. kg−1.d of protein (RT1), or
- RT +3.2 g/kg per day of protein (RT2).
The resistance exercise program consisted of two upper and two lower-body sessions each week, with participants performing four weekly sessions (Saturday, Monday, Wednesday, and Thursday). The program was linear periodized and lasted for 16 weeks. Participants performed three sets of 12 repetitions with 75% of a 1-RM for weeks 1–4, 3 sets of 10 repetitions with 80% of 1-RM for weeks 5–8, 4 sets of 8 repetitions with 85% of 1-RM for weeks 9–12, and 4 sets of 6 repetitions with 90% of 1-RM for weeks 13–16.
The endurance exercise program consisted of endurance cycle training on ergometers that consisted of a mixture of hill simulation rides of varying intensities (25–110 of maximum aerobic power (MAP), moderate-intensity continuous training at 50% MAP, moderate-intensity interval training (MICT) at 70% MAP, and high-intensity interval training (HIIT) at 100% MAP.
Results
All groups showed significant improvements in performance measures, lean mass, muscle strength, and power. However, peak power gains were notably higher in the higher protein group than lower protein and lower protein combined with endurance exercise. Specifically, lean mass increased by 3% in concurrent training with lower protein, 3.8% in concurrent training with higher protein, 3.5% in resistance training with lower protein, and 4% in resistance training with higher protein. These findings suggest that resistance and concurrent training can significantly increase lean mass when combined with higher protein intake.
Another interesting finding was that in the concurrent training + higher-protein group, energy intake increased by 428 calories compared to baseline, and 387 kcal in the resistance training only + higher protein group. Despite this increase in calories, the groups did not have increases in body fat. These are similar to other studies showing that increasing calories through protein does not increase body fat. (Antonio, Ellerbroek, Silver, Vargas, & Peacock, 2016; Antonio, Ellerbroek, Silver, Vargas, Tamayo, et al., 2016)
Aerobic capacity increased significantly in both resistance exercises combined with cardio groups. Some biochemical markers of kidney and liver function increased within the higher protein groups, but there were no between-group differences between the lower and higher protein groups. The study concluded that changes in kidney function did not differ between healthy adults consuming higher- compared with lower- or normal-protein diets.
The Verdict on High Protein Intake Kidney Damage
In conclusion, extensive evidence supports the safety of high-protein diets in athletes and healthy individuals. Contrary to popular belief, high protein cause kidney damage. The science behind protein and kidney function debunks the misconception that high protein cause kidney damage and is detrimental to renal health. Studies consistently show no association between high protein intake and kidney damage.
Athletes can confidently consume high levels of protein without concerns for kidney health. With the lack of evidence linking high-protein diets to kidney damage, individuals can enjoy the nutritional benefits of protein without worrying about adverse effects on their kidneys.
References
Antonio, J., Ellerbroek, A., Silver, T., Vargas, L., & Peacock, C. (2016). The effects of a high protein diet on indices of health and body composition–a crossover trial in resistance-trained men. J Int Soc Sports Nutr, 13, 3. https://doi.org/10.1186/s12970-016-0114-2
Antonio, J., Ellerbroek, A., Silver, T., Vargas, L., Tamayo, A., Buehn, R., & Peacock, C. A. (2016). A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. J Nutr Metab, 2016, 9104792. https://doi.org/10.1155/2016/9104792
Bagheri, R., Kargarfard, M., Sadeghi, R., Scott, D., & Camera, D. M. (2023). Effects of 16 weeks of two different high-protein diets with either resistance or concurrent training on body composition, muscular strength and performance, and markers of liver and kidney function in resistance-trained males. J Int Soc Sports Nutr, 20(1), 2236053. https://doi.org/10.1080/15502783.2023.2236053
Brändle, E., Sieberth, H. G., & Hautmann, R. E. (1996). Effect of chronic dietary protein intake on the renal function in healthy subjects. Eur J Clin Nutr, 50(11), 734-740.
Dellalieux, O. (2000). Do Regular High Protein Diets Have Potential Health Risks on Kidney Function in Athletes? International Journal of Sport Nutrition and Exercise Metabolism. https://doi.org/10.1123/ijsnem.10.1.28
References- Cont.
Ko, G. J., Obi, Y., Tortorici, A. R., & Kalantar-Zadeh, K. (2017). Dietary protein intake and chronic kidney disease. Curr Opin Clin Nutr Metab Care, 20(1), 77-85. https://doi.org/10.1097/mco.0000000000000342
Martin, W., Armstrong, L. E., & Rodriguez, N. (2013). Dietary Protein Intake and Renal Function. https://doi.org/10.1201/b16308-10
Martin, W. F., Armstrong, L. E., & Rodriguez, N. R. (2005). Dietary protein intake and renal function. Nutr Metab (Lond), 2, 25. https://doi.org/10.1186/1743-7075-2-25
Tarnopolsky, M. A., Atkinson, S. A., MacDougall, J. D., Chesley, A., Phillips, S. F., & Schwarcz, H. P. (1992). Evaluation of Protein Requirements for Trained Strength Athletes. Journal of Applied Physiology. https://doi.org/10.1152/jappl.1992.73.5.1986
Tipton, K. D. (2011). Efficacy and consequences of very-high-protein diets for athletes and exercisers. Proceedings of the Nutrition Society, 70(2), 205-214. https://doi.org/10.1017/S0029665111000024
Additional Information
The debate around high dietary protein intake and kidney function has gained traction on social media. While some claim it’s beneficial for weight loss, others argue it poses risk factors like hypertension and glomerular filtration rate (GFR) decline.
Kidneys are remarkable organs that filter waste compounds from the bloodstream. High blood pressure and obesity are known risk factors for kidney function decline.
Americans consume more protein than ever, often exceeding the recommended grams per kilogram of body weight. This protein consumption trend is especially popular among those engaged in weight training.
Observational studies suggest that a high proportion of protein in diets may lead to proteinuria and GFR decline. However, further analysis shows that this is more prevalent in individuals with pre-existing high-risk conditions like high blood pressure.
A low-protein diet is often recommended by nephrology experts as an important factor in managing those with poor kidney health. Dietary acid load is also a concern, often exacerbated by low-carbohydrate diets rich in animal protein.
While protein aids in satiety and weight loss, overweight individuals should consider current dietary approaches. The effects of high protein intake are complex and require further analysis. Always consult healthcare professionals for personalized advice.
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