Whey protein is a key component of milk – the part that separates during cheese making. Despite its humble origin, it has a number of features that have made it popular among those into health and fitness.
• Whey is a complete protein: it contains all nine essential amino acids, and particularly high levels of branched-chain amino acids (BCAAS) like leucine, primary drivers of muscle protein synthesis, says Cape Town-based sports dietitian Hanlie Jordaan.
• It is rapidly digested and absorbed (faster than almost any other protein source). The amino acids it contains reach the bloodstream within about 20 minutes of consumption, making it useful for post-workout recovery.
• It is convenient and versatile. Unlike whole food protein sources such as chicken and eggs, which need cooking, whey protein is easily mixed with water or milk, and can be blended into shakes, baked goods or oats.
• It helps weight management. “It promotes a feeling of fullness, regulates energy and helps preserve calorie-burning lean muscle mass while losing fat,” says Jordaan.
• It provides continuous dietary support. Supplementing with it can be a way to bridge gaps in your diet if you struggle to meet your daily protein needs through whole foods alone.
• It is cost-effective. Calculating the cost per gram of protein, whey concentrate (70-80% of protein, with low levels of lactose and fat) and whey isolate (90-95% protein, with almost all fat and lactose removed) are often more affordable and accessible than high-quality meats and fish. (Whey hydrolysate can have varied protein content and cost more, but has the advantage of being ‘predigested’, having already undergone partial breakdown, which reduces digestion time compared to the other types.)
Benefits of whey protein
Muscle-building: This is the most common reason people take it. The minimum protein requirement for most people is 0.8 grams per kilogram of body weight a day, but this is often not enough for athletes and those focused on building muscle, says Jordaan.
Weight gain: Whey is an easily-digested source of calories and protein, making it potentially helpful in cases of involuntary weight loss and muscle wasting (sarcopenia) in older people who are not getting enough protein, studies show1. “Combined with resistance exercise, it may help older adults build strength and maintain mobility,” she says.
Wound healing: Protein is vital for tissue repair, and whey protein provides a rapid amino acid supply for collagen synthesis and tissue regeneration. Several studies2 have shown whey supplementation can help speed up wound closure and reduce complications such as infections.
Allergies and dermatitis: While intact cow’s milk can sometimes trigger eczema flares, partially hydrolysed whey protein (a specific type of whey hydrolysate) is especially processed to prevent immune system overreactions and has shown promise for those with allergies such as eczema3, although more research is needed.
Potential drawbacks
For all its benefits, excessive protein can have side-effects, and caution is advised when using this or any other supplement, says Jordaan.
In a recent investigation in the journal Healthcare4 into the health implications of the increasing consumption of whey protein, whey protein was found to a have beneficial impact on gut function and microbiota, enhancing the gut barrier and reducing inflammation. It also had a positive impact on bone health, potentially aiding in bone density and strength, and evidence was in favour if its maintenance of good muscle.
“However, if you are someone with liver disease or pre-existing kidney disease, then adding excess protein to the diet, in any form, can put too much strain on the liver and kidneys,” cautions Jordaan. “Some people can experience gastrointestinal comfort, such as bloating, gas, abdominal pain or diarrhoea. This could be from the lactose in the whey or from the sweetener used in the product. Whey isolate or hydrolysed whey may be better tolerated, and look for an unflavoured option.”
Supplements alone will not unlock your potential, she says – your overall nutrition strategy will. “A personalised meal plan and evidence-based guidance from a registered sports dietitian can help you train harder, recover faster, reduce injury risk, and achieve the results you’ve been working for. Invest in your nutrition as intentionally as you invest in your training.”
References
1. https://pmc.ncbi.nlm.nih.gov/articles/PMC9998208/
2. https://pubmed.ncbi.nlm.nih.gov/41661261/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC5527395/
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC10815430/