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Does whey protein affect kidneys? [Diagnosed]
There are many doubts about whey proteins, one of which is “Does Whey protein affect kidneys”? You may have heard it somewhere, or even read about it in some article.
But let me tell you, whey protein does not damage or affect kidneys in healthy people.
Consuming whey protein is one of the effective and efficient ways to fulfill daily protein requirements. Whey protein has been on the market for the last couple of decade. It is one of the oldest and most researched bodybuilding supplements. Whey has been a subject of thorough research and analysis.
Whey protein help stimulates muscle protein synthesis, maintain and gain muscle mass. It also maintains a positive nitrogen balance in the body besides playing important roles in the body.
Various nutrition supplements use whey protein as the source of proteins. It is present in right from baby formulas to supplements for the elderly.
Whey protein is one of the safest, well-studied, and a high-quality protein supplements. It is deemed as safe and approved as a food ingredient by both USFDA and FSSAI.
In this article, let’s take a look at the origin of this misconception “Whey Protein damages kidney” and discuss the reason behind this argument. Besides, take a look at some research to see if whey protein or any protein consumed in excess or in required quantity damages kidneys.
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Content
- The origin of doubt “does Whey Protein affect Kidneys”
- A high protein diet for 1 year does not have any adverse effect on kidney
- The effect of high protein intake in overweight patients did not have any detrimental effects on the kidney.
- A high protein diet in overweight subjects for 6 months did not affect the kidney.
- Conclusion
The origin of doubt “does Whey Protein affect kidneys”
This original assumption was “Prolonged consumption of high protein diet damages kidney”. Which has morphed into “Consumption of whey protein damages kidney”.In 1983 Dr. Barry Brenner proposed a hypothesis in a nephology forum (1). It hypothesized that prolonged consumption of dietary proteins can cause damage to the kidneys. Here he did not make any mention to proteins obtained from supplements or whey.
A higher intake of protein causes an increase in the metabolites. This leads to a higher glomerular filtration rate and glomerular pressure to excrete the metabolites (2).
GFR rate: “Glomerular filtration rate (GFR) is a test used to check how well the kidneys are working. Specifically, it estimates how much blood passes through the glomeruli each minute. Glomeruli are the tiny filters in the kidneys that filter waste from the blood” (3).
Dr. Brenner hypothesized a higher glomerular filtration for a prolonged period can cause renal injury. Which can compromise renal function leading to progression of renal disease (1).
But the majority of the evidence in this paper was based on animal models and subjects with existing kidney conditions. The extent of response to GFR varies significantly depending on species. Hence it is not appropriate to apply the same data to healthy subjects with no kidney condition.
An increase in glomerular filtration is the normal adaptive mechanism of the body in response to various conditions (4). This adaptive mechanism of increasing GFR does not contribute to kidney disease in healthy patients (5). Evidence suggests with increased dietary intake of proteins renal systems undergoes various changes. But these changes do not show any detrimental effects on the renal system.
The GFR in healthy women increases as much as 65% during pregnancy which returns to normal post-pregnancy (6). One may assume that frequent and prolonged increases in GFR may cause renal injury, but that is also not the case. The frequent GFR increase in the case of multiple pregnancies did not cause any adverse effect on kidneys (7).
Another group postulated that protein consumption increases urea production. Since kidneys are responsible for the excretion of urea, this increased workload can stress the kidney.
Our kidneys can excrete up to 25 grams of urea per day. 60 grams of protein produces about 2.5 grams of urea, which is only about 1/10th of the maximal capacity of our kidneys. Hence it does not seem likely that consumption of protein will stress the kidney due to increased urea production.
There is no evidence to suggest that increased GFR or increased urea production due to protein consumption can cause any damage to the kidneys. Also as noted above increase in GFR is the normal adaptive mechanism of the body and does not indicate any adverse effect on kidneys.
To further clarify this let’s take a look at a couple of researches to see if increased protein intake has any adverse effect on the kidneys.
A high protein diet for 1 year does not have any adverse effect on the kidney– “Whey supplements do not cause any harm to the kidney”.
In a study performed by Jose Antonio titled “A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males” (8). Dr. Jose Antonio found no adverse effect of prolonged consumption of protein on kidneys.
This research carries a special significance since this is one of the longest studies performed. In this study subjects consumed about 3 grams of protein/ kg of body weight/ day. Also, the study was performed on subjects who had experience in resistance training. During the study, all subjects underwent resistance exercises.
This study relates to most of the bodybuilders and fitness enthusiasts who are consuming protein supplements as a part of their diet.
14 healthy subjects underwent the study. The subjects consumed their normal diet for 6 months and high protein diet for 6 months. For both diets subjects consumed 2.51 and 3.32 grams of protein /kg of body weight/ day respectively.
Subjects used whey protein to fulfill the higher protein requirements.
Even the normal diet of the subjects contained three times more protein than the normal requirements.
Various tests were performed to indicate blood lipid levels, liver and kidney functions at the end of the study
# indicates >60 mL/min/1.73m3
The table above shows the values of various kidney function tests (BUN mg/dL, Creatinine mg/dL, eGFR, and BUN/ Creatinine ratio) after one year of the study.
The results show all the values to be normal and within the reference range. Even if the values seem to be at the higher end, we have to consider the baseline values which are also towards the higher end.
The values did for the kidney function test did not change much from baseline for both normal and high protein diet.
The test measurements indicated no harmful effects of higher protein consumption on kidney, liver, and blood lipid levels. It shows that high protein diet for 1 year did not have any adverse impact on the kidneys.
The effect of high protein intake in overweight patients did not have any detrimental effects on the kidney. – “Dietary proteins have the same effect on the body as protein supplements”.
In this study let’s take a look at what happens when we increase our protein intake via dietary protein. Does it differ from the effects produced by protein supplements? Also, the study was performed on obese individuals. Obese individuals already have a higher GFR rate, and we know higher protein intake increases GFR rate further. Will that have any detrimental effect on kidneys?The Clinical Journal of the American Society of Nephrology published a study titled “Comparative Effects of Low-Carbohydrate High-Protein Versus Low-Fat Diets on the kidney” (9).
This study was performed on overweight subjects to determine the effects of low carb, high protein weight loss diet on the kidney.
Although it was a weight loss diet, it included consumption of a higher amount of proteins for 2 years. The age of subjects was much diverse, 18-64, and the study had 307 adults as subjects. So the results carry do a great significance to normal adults.
In this study, 154 participants were assigned to the low carb- high protein diet, while the rest half was assigned to the low-fat diet.
The low carb diet had restrictions on carbohydrate consumption and no restriction on fat and protein. The participants could eat as many fats and protein as they want.
The low-fat diet was designed in such a way that only 15% of the total calories came from protein.
Various measurements to indicate kidney function were taken at the baseline, 3, 12, and 24 months.
Given overweight patients already have higher GFR, the author expected that the diet-induced increase in GFR may have some detrimental effect on the kidney.
The damage to the kidneys is indicated by decrease in the GFR. But the authors did not find any decrease in the GFR at the end of the study indicating normal kidney and renal function.
At the end of the 24 months, the authors did not see any harmful effects on the kidney. The authors concluded that the high protein diet is not associated with any noticeable harmful effects on renal function.
This study shows the dietary protein has similar effects on the body as the protein obtained from supplements. Research shows that high protein diet also increases GFR as intravenous infusion of amino acids do (10).
So there is no reason to assume consuming whey protein supplements can damage kidneys. The body treats protein from both sources the same way.
A high protein diet in overweight subjects for 6 months did not affect the kidney. – “Body undergoes adaptive changes according to the diet”.
A study “Changes in renal function during weight loss induced by high vs low-protein low-fat diets in overweight subjects” (11) was conducted over 6 months. The authors did not find adverse effects of a high protein diet on the kidney.
This study was like the previous study we looked at, but this study has some interesting aspects. This study included both a low protein and a control group in addition to the high protein group. So it is possible to compare the effect of different diets on our body and if the effect is harmful.
The study included 56 subjects aged from 18-56 and divided into low, high protein, and a control group.
Again the protein consumption was determined as the percentage of daily calories instead of the gram/ kg of body weight/ day measure.
Various measurements were taken to indicate kidney function before and after the study. None of the measurements indicated any adverse effects on renal function.
The important observation of this study is that the body undergoes adaptive changes according to the dietary input. For example, in the low protein group the size of the kidney decreased as well the GFR rate. In the high protein group, the size of the kidney increased as well the GFR rate.
This observation shows that body undergoes adaptive changes in renal size to accommodate the increase or decrease in the GFR. The GFR changed to accommodate the diet.
The changes were normal and did not show any adverse effect on renal function.
“The capacity to increase GFR in response to protein feeding, known as kidney functional reserve, is a normal adaptive function of the kidney to increase solute clearance in response to an increase in solute load (i.e., nitrogen load). Importantly, this adaptive response does not represent a risk factor for the development of Chronic Kidney Disease12).
Of course, there are plenty of articles and research out there that show the same evidence. I picked these three studies because these three also do a good job of addressing the main concerns.
Conclusion:
- The hypothesis “consumption of protein for prolonged duration damages kidney” is based on animal models, and subjects with an existing kidney condition. It is not appropriate to apply the same data to the subjects with normal kidney function.
- The increase in GFR is a normal adaptive mechanism of the body and the GFR also increases in response to various conditions such as pregnancy. The increase in GFR is an adaptive response of the body and does not cause any damage to the kidney.
- Prolonged consumption of protein supplements does not cause any damage to the kidney in resistance-trained individuals even if consumed in excess.
- The changes observed in renal function are the same for both dietary proteins and proteins obtained from supplements.
- There is no reason to assume that whey protein or protein supplement causes any harm to renal function in healthy individuals.
- Consumption of dietary protein, excess protein, or whey protein supplements does not have any adverse effect on the kidneys in healthy people.
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