Although you can survive with just one, your kidneys are responsible for some pretty important things, including:
filtering your blood, getting rid of any waste or toxins
regulate how much water and various salts you have in your blood
help maintain blood pH (how acidic or alkaline your blood is)
production of hormones
There’s been some talk for some time that a very high-protein diet can cause damage to your kidneys, which is understandably a cause for concern.
However, a study by the Journal of International Society of Sports Nutrition in 2017, showed that “although excessive intake is a concern for anyone with a pre-existing renal / kidney disease, the chronic consumption of a high protein diet (i.e., for 1 year) had no harmful effects on kidney or liver function. Furthermore, there were no alterations in clinical markers of metabolism and blood lipids.”
In addition to this, another study into Dietary Protein Intake and Renal Function suggests, “evidence suggests that protein-induced changes in renal function are likely a normal adaptative mechanism well within the functional limits of a healthy kidney… At present, there is not sufficient proof to warrant public health directives aimed at restricting dietary protein intake in healthy adults for the purpose of preserving renal function.”
However, as always, it’s important to remember that eating a balanced diet is key, and if you’re eating a large amount of meat and dairy on a daily basis, consuming an additional 3 protein shakes isn't necessary.