Do Protein Supplements Help or Harm?

Many claims are made about the ‘dangers’ of protein supplements but these claims don’t stand up to scrutiny.

Are protein powders damaging to the kidneys?

This belief is common because those with kidney disease benefit from a lower protein diet (1) (as protein IS detrimental if your kidneys are already damaged). But while higher protein diets might worsen things for those with existing kidney disease, they do not cause kidney disease. There is no evidence that high protein diets containing far higher levels of protein than RDA recommendations cause any detrimental effects on the kidneys or kidney function. (2, 3)

Do protein powders ‘overload’ the kidneys and liver?

Overall, there doesn’t appear to be any evidence that the kidneys and liver become ‘overloaded’ in healthy people taking protein supplements or eating high protein diets. The International Society of Sports Nutrition Position on Protein and Exercise draws attention to controlled investigations applying what is considered very high protein intakes of 2.5–3.3 g/kg/day (approximately 4X the RDA) concluding that:

Are protein powders bad for your bones?

The largest systematic review and meta-analysis of this topic has concluded that this claim is untrue. There is no detriment to bone health from higher protein diets, and in contrast, protein supplementation actually improves bone health. (5)

What does it mean that protein powders are ‘denatured’?

This claim doesn’t really make a lot of sense because whether or not there is some denaturing of protein during the manufacturing process makes no difference. While the term ‘denaturing’ can sound scary (like you’re creating some Frankenstein’s Monster food), denaturing is a normal process and many of the foods we commonly eat contain denatured proteins.

Do we know the long-term health effects of protein powder?

Higher protein diets have been used by athletes since ancient times. More recently protein supplements have been used since the early 1900s, with egg protein powders becoming common from the 1950s onwards with the rise of bodybuilding and ‘physical culture’. Other proteins like whey, casein, soy and more recently other vegetable proteins, have risen in popularity from the 1980s on. So, there has been at least a millennium of high protein use by athletes, around a century of some use and more frequent and common use for over 30 years with no detrimental effects seen. In the absence of any robust hypothesis as to why they may be harmful and with all available evidence pointing to safety, we must discard this claim as false.

Can the body ‘recognise’ protein supplements?

The claim that the body can’t ‘recognise’ protein powder as food is one of the most nonsensical statements that people make. It is based on the ‘naturalistic fallacy’ that ‘natural’ foods are arbitrarily and universally better than anything created by man.

Can the body absorb and utilise protein powder?

A similar claim to the preceding one, which also lacks any truth. There are literally thousands of papers that show the utility of protein powders, something that couldn’t be evident if they weren’t absorbed or utilised by the human body. In the case of pea proteins, as an example, it has been demonstrated that there are extremely high absorption rates from the digestive tract (over 89%), (6) and that these proteins effectively improve muscle protein synthesis and support muscle growth and maintenance. (7)

But, prescribing protein supplements isn’t ‘holistic’?…

I have been criticised for including protein powders in client plans because it is claimed that to do so isn’t ‘holistic’. My counterclaim would be that to arbitrarily avoid protein powders is in fact anti-holistic.

Don’t we already get too much protein from our diets?

To address this claim, we need to consider what we need and what is, in fact, too much?

How could protein powders help me?

Protein powders aren’t magical, and they won’t suddenly cause you to shed fat or gain muscle and they’re certainly no better than whole food. BUT they can offer significant benefits.


Protein powders are convenient. Many people struggle to have good quality meals, consistently. Protein powders can provide the ‘base’ for simple, effective, nutrient-dense meals when prep time is short or when you are struggling to come up with meal ideas! Many of my clients use a protein smoothie (with healthy fats, veggies and berries added!) daily to provide one of their meals.

For use in and around training

Many athletes benefit from protein either before, during, or after training. Eating whole food may not be ideal for these times and protein powders offer a convenient, easy-on-the-gut option for peri-training nutrition.

Bolstering the protein content of the diet easily

As mentioned above, many people actually don’t get the protein they require to perform at their best or to meet specific needs like increased protein intake during dieting. If the rest of the diet is robust and nutrient-dense, an easy ‘fix’ can be to simply add a shake or two during the day.

Other benefits of protein supplementation

(especially if you’re not currently eating enough protein!)

  • Improved ‘lean muscle’
  • Improved bone health
  • Increased satiety
  • Improved cardiovascular health


Don’t be scared of protein supplements! While they’re not essential, they can be used as a convenient way to boost your protein intake to the levels that are consistent with your desired health and performance outcomes.


1. Fouque D, Laville M. Low protein diets for chronic kidney disease in non diabetic adults. The Cochrane Library. 2009.



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