Excessive warnings about protein powders, creatine scoops and heavy gym routines have been flooding social media, often suggesting that these supplements can strain the kidneys or even trigger kidney failure. With fitness culture booming, so has the confusion. A UK-based NHS surgeon has now broken down what the science actually says and his message is reassuring for most people.
In an Instagram video posted on November 18, Dr Karan Rajan, surgeon and widely followed health educator, explained how these supplements interact with kidney function and who actually needs to be cautious.
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‘Healthy kidneys can handle high protein,’ says Dr Rajan
Addressing concerns around high protein intake, Dr Rajan said protein shakes are unlikely to harm most people.
“If you have a healthy pair of kidneys, there is ample evidence that high protein diets do not affect kidney function, even up to three grams per kilo of protein a day, which is an insane amount,” he said, adding humorously that such high intake “can’t guarantee you won’t have violent protein farts.”
However, the surgeon noted that people with existing kidney disease fall into a different category. Research shows that low-protein diets help slow the progression of chronic kidney disease, reduce the risk of kidney failure and delay the need for dialysis.
“This can delay kidney disease progression, decrease the risk of kidney failure, and the need for dialysis,” he said.
Creatine warnings apply only to those with kidney issues
Dr Rajan also addressed creatine which is one of the most widely used gym supplements. He said that creatine does not harm healthy kidneys.
“Healthy kidneys are not harmed by creatine supplementation,” he explained, noting that no evidence supports claims of creatine-induced kidney toxicity in healthy individuals.
The risk, he said, applies to people with pre-existing kidney issues, since there is insufficient long-term data on creatine use in such cases. For them, it is best avoided.
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Because creatine can raise serum creatinine levels, a common marker used to assess kidney function, Dr Rajan advised more accurate testing.
“If you're taking creatine and getting blood tests, I suggest using blood markers that don't rely just on serum creatinine… consider using cystatin C instead,” he said.
