Of all of the myths that abound when it comes to nutrition, the assumptions that surround protein consumption and kidney damage seem to be the one everyone talks about most often. How did it start? From the research, I did this particular myth started from research on patients with kidney disease. And why is that?
People with kidney disease have difficulty of filtrating protein, and that’s why in some cases they are on a low-protein diet. So, the conclusion was made that because patients with kidney disease could not filtrate protein, then it must be that too much protein must be hard on the kidneys. Awesome right?
In reality, studies have been done on higher protein intakes, and the result is that higher protein intake is completely safe. In the short-term, the body adapts to the higher protein intakes which changes some markers of kidney function.
This is part of the adaptation process to the additional protein. However, long-term consumption of higher amounts of protein do not have a negative impact on kidney function.1,2,3,4,5
When I talk about Dr. Jose Antonio’s latest study,2 even with the amount of protein consumed, the author states: “There were no changes in any of the variables regarding blood lipids and a comprehensive metabolic panel.
We examined the two individuals with the highest recorded protein intakes (4.66 and 6.59 g/kg/day) and found no deleterious effects on renal function in either individual.”
We know from previous studies that high in protein diets cause hyperfiltration and we should expect an initial increase in glomerular filtration (GFR). Glomerular what? The glomerular rate is the best test to measure your level of kidney function and determine your stage of kidney disease.
But as a study5 concludes, “A healthy diet rich in protein increased eGFR (Estimated glomerular filtration is a test that is used to assess how well your kidneys are working. The test estimates the volume of blood that is filtered by your kidneys over a given period of time.
The test is called ‘estimated’ because the glomeruli are the tiny filters in the kidneys. If these filters do not do their job properly then the kidney is said to have reduced or impaired kidney function). Whether long-term consumption of a high-protein diet leads to kidney disease is uncertain.”
The claim that protein intake leads to kidney stones or kidney failure is not supported by the facts.
References:
1. Antonio, J., Ellerbroek, A., Silver, T., Orris, S., Scheiner, M., Gonzalez, A. and Peacock, C. A., 2015. A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women – a follow-up investigation. Journal of the International Society of Sports Nutrition, 12 (1).
2. Antonio, J., Ellerbroek, A., Silver, T., Vargas, L. and Peacock, C., 2016. The effects of a high protein diet on indices of health and body composition – a crossover trial in resistance-trained men. Journal of the International Society of Sports Nutrition, 13 (1).
3. Li, Z., Treyzon, L., Chen, S., Yan, E., Thames, G. and Carpenter, C. L., 2010. Protein-enriched meal replacements do not adversely affect liver, kidney or bone density: An outpatient randomized controlled trial. Nutrition Journal, 9 (1), 72.
4. Friedman, A. N., Ogden, L. G., Foster, G. D., Klein, S., Stein, R., Miller, B., Hill, J. O., Brill, C., Bailer, B., Rosenbaum, D. R. and Wyatt, H. R., 2012. Comparative effects of low-carbohydrate high-protein versus low-fat diets on the kidney. Clinical Journal of the American Society of Nephrology, 7 (7), 1103–1111.
5. Juraschek, S. P., Appel, L. J., Anderson, C. A. M. and Miller, E. R., 2013. Effect of a high-protein diet on kidney function in healthy adults: Results from the OmniHeart trial. American Journal of Kidney Diseases, 61 (4), 547–554.