Sometimes, no matter how much data you try to deny false information, the lie will still be great. This lie, for example, is the myth that high protein intake is harmful to the kidneys. So what is the scientific community doing with this myth? He’s buried deeply.
That’s exactly what Dr. Stuart M Phillips and his fantastic team of scientists did after the publication of the meta-analysis covering the results of 28 trials involving more than 1,300 participants.
After compiling and analyzing the data, we have a clear verdict on what the study says.
Selection of tests
Meta-analysis is as good as the research it uses. To get the right research, the researchers were only interested in studies comparing high protein diets with lower protein diets. In this context,
Definition High protein diet (HP group)
≥ 1.5 g protein per kg body weight
≥ 20% energy consumption or
≥ 100 g protein / day
Definition Normal or Lower protein diet (NLP group)
≥ 5% lower energy consumption from protein per day compared to the high protein group
All the others were not taken into account when developing the meta-analysis, leaving a total of 28 studies.
What is the glomerular filtration rate (GFR)?
Glomerular filtration is the first step in urine production, and glomerular filtration rate (GFR) is the volume of fluid that is filtered to the second stage at a given time. On average, people filter 125 ml per minute or 180 litres per day. The biological process is quite complex, and if you’re interested, there are fantastic videos on YouTube that show it from beginning to end.
This is important because GFR is a simple way to check how well your kidneys work. There is a healthy range of GFR, and it’s too low value is the most common diagnosis of kidney problems, although too high results may also indicate problems.
Phillips and his team used GFR, because it is actually used as an argument for abandoning a high-protein diet. The theory that protein affects kidney function is due to an increased charge of soluble substance in the kidneys (as urea), which can ultimately lead to kidney glomerulopathy, kidney damage and ultimately loss of health. Urea is a nitrogen compound that your kidneys need to filter, and it was originally thought that all this urea filtration could ultimately lead to kidney failure.
Although this may be true for people with impaired renal function, there is no evidence that the same applies to healthy people, and recent studies have shown no additional benefits in low-protein diets in patients with renal insufficiency, which raises the question of whether protein is really a first-rate problem.
Coming back to this meta-analysis, certainly, if these diets were to contribute to kidney damage, their actions would be visible in studies of GFR level, which was the cornerstone of the myth of kidney damage.
So what was the final verdict?
A simple dietary protein has no effect on the GFR index, therefore a high protein diet does not adversely affect the kidneys. In short, people with a high-protein diet had higher GFR at the end of the study.
While some may hypothesize that people using a high-protein diet generally live healthier and more active, the data indicate a generally better kidney function, although to be honest, we are most interested in people who want to live a healthy/active lifestyle in the first place.
Bet on protein!
The theory of protein leverage effectively concludes that animals (including humans) have priorities for protein and easily absorb surpluses of fats and carbohydrates to get the right amount of protein. In short, your body will get this protein, regardless of whether it comes from steak or two pails of ice cream. That’s why you use protein, giving it priority in every meal – it’s a topic for the next article.
The fear-provoking level of urea in the blood, with which healthy kidneys have no problems, is exactly the thing that you should not bother an obese person whose body needs almost only protein, because he has a large supply of energy.
Needless to say, Phillips and the team knew that society desperately needed a better structured, better-written meta-analysis.
Conclusion – this kidney myth has to die. The protein is beneficial.
Dr Phillips and the team have so far conducted the best meta-analysis on this topic, and there has been so much data to confirm that any debate has been paused at the moment.
People are well adapted not only to intermittent fasting, but also to intermittent feasting. We can eat large amounts of protein, and fish yet protein of animal origin are the best and the most abundant source of this protein. Our bodies treat the consumption of this protein as a priority, going to potentially mad amounts of food consumed to get the right amount.
When we feast on this protein, is urea by-product increased? Of course. Does this, however, destroy our kidney function? No. This is exactly what the kidney is adapted for.
For almost the entire population, we can confidently say that the benefits of a high-protein diet are huge and that the myth of your whey shake closing the kidneys is officially denied.