By Christopher Tack |
Clinical Specialist Physiotherapist
Whey protein has a reputation.
Of all the forms and types and strands of the much-loved protein, whey protein is the King.
Its proposed benefits on muscle development make it hugely popular and recognisable as one of the most common and widespread sports nutrition supplements (32-33). Due to this prevalent use by gym goers and sports people, it has also been the subject of a vast amount of scientific literature.
The purpose of this article is to cut through all of this literature to give you, the average gym goer or athlete, the real facts regarding Whey Protein to help you decide if Whey is the way to go.
What Is Whey Protein?
Whey used to be considered a waste by-product of cheese and curd manufacturing. Approximately 20% of the protein in cows’ milk is whey. During the industrial production of cheese and curd, milk goes through a structured process which includes pasteurisation, inoculation and incubation before Rennet extract is added.
The addition of Rennet extract (a complex of enzymes taken from the stomachs of newborn calves) assists the coagulation of milk and separates it into curds and whey (remember Little Miss Muffet?)
The Difference Between Whey Concentrate & Isolate
The newly separated mixture is then filtered and neutralised with citric acid. Continuous filtration of this liquid whey concentrates its protein percentage down to 80% protein. Further microfiltration can boost protein concentration up to 90% (13)! The liquid whey solution is then warmed and spray dried to become a whey protein powder. This is often described as whey Concentrate and still includes a level of fat and carbohydrates (in the form of lactose).
This form of protein can have between 29-90% total protein but 70% and 80% concentrations are the most commonly seen in sports nutrition supplements (13-14).
There are also variations on whey protein based upon different manufacturing processes which are applied to the whey. These are labelled as Isolate (where water is removed along with all lactose and cholesterol leading to a 95% protein concentration) and Hydrolysate (where the whey is partially pre-digested with enzymes to reduce the size of the peptide molecules and to accelerate absorption and amino acid availability) (47). Whey protein hydrolysate is commonly suggested to be the optimal form of whey protein (67).
The Benefits of Whey Protein
The focus in this piece is predominantly in examining the effect of whey protein on healthy individuals.
This is simply for succinctness as it would be difficult to examine each potentially benefited subgroup in detail. As such we are unable to delve into all the added benefits for specific special populations despite likely benefits.
For example, whey can be consumed alongside vitamin D and exercise to boost fat-free mass, strength, functional outcomes and well-being in the elderly to combat age-related muscle mass decline (63).
It is clear from the scientific literature that the vast majority of the research supports the idea that people who engage in exercise and sport regularly require more protein in their diet or via supplementation than people who are sedentary (13). This is down to the need to consume protein to reach a positive net protein balance.
Benefits | Muscle Protein Synthesis
The amount of muscle gained or lost is a reflection of protein metabolism. Simply put, protein accretion or protein loss is decided upon a careful balance of muscle protein synthesis (MPS) and muscle protein breakdown (54).
Protein and amino acid consumption (through diet or supplementation) will stimulate MPS and a positive net protein balance, whilst fasting will lead to higher rate of breakdown and a negative net protein balance (5). Healthy, active people have a protein turnover rate of 1.5-2% per day (17).
Breakdown of skeletal muscle protein is also caused by exercise; meaning in order to sustain a positive protein balance, an individual would need to consume more protein.
So, this shows that exercising individuals have a need to consume more protein- however, does whey protein assist in this task?
Several well-designed studies have shown that whey protein supplementation specifically, with dosages varying from 20g-40g, is effective in maximising the stimulation of muscle protein synthesis in all individuals respective of age (29,67,73).
This shows that biologically whey protein can induce the stimulation of MPS, but is this effect transferable to us as humans?
Benefits | Whey Protein and Performance
Importantly for athletes and sports people, alongside the physiological changes apparent with whey protein supplementation, there is also likely performance related benefits reported.
The benefits of non-specific protein supplementation on resistance training exercise performance and post-exercise adaptations have been outlined in a large meta-analysis study of 22 trials (16).
Based on data from 680 participants, the combined findings showed not only a 0.91kg increase in fat-free mass but also a 20.7kg greater increase in 1 rep max single leg press strength! Now as stated this is not specific to whey protein – however, as the most fast-acting and readily absorbed protein source, it goes without saying it is likely whey protein will replicate these benefits.
Whey Protein Dosage
Firstly, we need to establish the recommended daily allowance advised to sustain a balance of protein synthesis versus degradation in healthy adults, to account for differences in protein metabolism and nitrogen losses (via urination and excretion).
This value is 0.8g per kg of body weight daily (35), which for an average 80kg man would be:
0.8g x 80kg bodyweight = 64g per day
This value is suggested to cover 97.5% of healthy men and women over the age of 19 years old. However, it is also advised that the cost of exercising in regards to protein metabolism will be greater in those who exercise and require more protein to allow lean tissue development and repair post-training (36,68). In fact, the predominant nutritional guidelines for protein consumption suggest that for physically active people up to 2g per kg per day is both safe and more effective post-training (13).
Such guidelines also suggest that whilst every step should be taken to obtain protein via whole foods in the diet, protein supplementation through sources such as whey is an effective and efficient way of making sure protein intake is met (13).
For the purposes of clarity, we will now outline the proposed dosage recommendations for varied forms of activity and exercise, as each will predispose the participant to different physical stressors which may require a different amount of protein consumption.
Whey Dosage For Endurance Athletes
Generally, protein intake should range from 1g/ kg to 1.6g/ kg depending upon the duration and intensity of performance (27,43,49,69).
The advised dosage for 2 bouts of 90 minutes cycling at 46% VO2 max was 1g per kg per day (21).
A dosage of 1.6g per kg per day meets the protein (nitrogen balance) requirements for experienced runners (70).
In an elite running population, this requirement is suggested to reduce to 1.49g per kg per day (25).
Whey Dosage For Strength Training
It is likely obvious to most that activities involving strength, such as weightlifting and bodybuilding have a higher protein requirement than endurance activities. This is particularly evident when undertaking the early stages of training or when the volume of exercise changes dramatically.
However, the scientific literature does not have a specific dosage which is more commonly quoted for this population. Rather a range of protein consumption levels is usually seen.
1.2-1.8g per kg per day is suggested to stimulate lean muscle mass accretion (1,16,38,42,69-70).
This same dosage (1.2-1.8g) will facilitate adaptations to training if sufficient calories are provided also (57-58,65,71,75-76,80).
Bodybuilders are suggested to consume 1.12g per kg per day specifically (70).
Power sports athletes (such as Olympic weightlifting) are suggested to consume between 1.6-2g per kg per day (2,36,42,44,69).
Doses of 2.3-3.1g per kg per day are suggested for bodybuilders (31) as a higher intake is proposed to sustain lean body mass (LBM), with sufficient carbohydrates and reduced fat intake (30,50,). Intense resistance training (alongside calorie restriction) can lead to a negative nitrogen balance (NNB) despite 2g/kg protein consumed (12,15).
Whey Protein For Intermittent Sports
A protein intake of 1.4-1.7g per kg per day is recommended for athletes undertaking activities which are intermittent in nature (45). This would include sports such as football or basketball.
Despite occasional allegations being made regarding negative effects of high whey protein consumption, there is a dearth of conclusive evidence to support such claims (32).
In fact claims regarding the impact on the health of the kidneys (40), bone density (39), liver (53) and cardiovascular system (33) have all been scientifically questioned or entirely disproven.
Take Home Message
Whey protein supplements give us the perfect opportunity to ensure our post activity protein metabolism remains in balance. They are a high-quality protein source which is easily absorbed and provides all essential amino acids required to boost muscle protein synthesis and develop lean body mass.
Also, they are handily available in a variety of flavours to provide a quick hit of protein to supplement your daily protein dietary intake. No wonder they are one, if not the, most popular supplements around.
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