Learn about Whey Protein Isolate (WPI)
and Hydrolysed Whey Protein Isolate (HWPI)
Whey protein isolate also known as WPI is the most popular of all whey protein products sold in the gym supplement market today. It offers a high percentage of whey protein per serve and there is a significant reduction in the risk of side effects (mainly bloating) that are commonly associated with the more natural whey protein concentrate (WPC).
Throughout this article we will discuss the pros and cons of using WPI as a protein supplement and what to look for when choosing the best protein product to suit your needs.
What is Whey Protein Isolate?
As seen in the diagram below, after separating the dairy milk proteins into casein and whey, whey protein concentrate forms the foundation of all whey protein products. Whey protein isolate is then created by removing lactose (milk sugar) and fat from WPC through a process of filtration to craft a more refined, designer whey product.
Which WPI Filtration Method is best?
There are essentially 2 types of filtration methods used when refining WPI, ion exchange and cross-flow filtration. There are pros and cons to both methods and this is normally reflective in their price.
Whey protein ion exchange filtration is a chemical process where chemicals are used to breakdown the whey protein solution into individual molecules, which are then separated by an electrical charge. An advantage to this method is that ion exchange filtration will generally result in WPI products with the smallest amount of fat and lactose and the highest percentage of protein. The disadvantage is that during ion exchange filtration a number of the amino acids that make up whey protein are also broken down which results in them losing their biological value (ability to be utilized within the body to make protein and build muscle).
In summary, ion exchange whey protein isolate products will have a higher percentage of whey protein, but due to the breakdown of some amino acids it will also have a lower biological value. Essentially a higher protein percentage, but in a form that is slightly less useful to the body.
Cross flow filtration is a chemical-free process that uses a semi-permeable membrane to help filter a whey protein solution based on the size of its molecules. There are different degrees of cross-filtration that WPI products can go through to help isolate the whey protein molecules from unwanted ingredients such as fat and lactose. These include microfiltration, ultrafiltration and nanofiltration. What's the difference? The pore size of the semi-permeable membrane and essentially the size of the molecules that can pass through the filter.
Microfiltration is the most basic form of whey protein isolate filtration and is also the cheapest. Products that go through microfiltration will still contain a small percentage of carbohydrate and fat.
Ultrafiltration is the next step up in filtration. The molecules that are small enough to pass through the membranes of microfiltration (above), may be too big in ultrafiltraion, which helps to produce a more refined product with less lactose and fat.
Nanofiltration is the most refined process allowing only the smallest of molecules (less than 1 nanometer) to pass through the filter. This type of filtration method can also be used to help separate individual amino acids to create a whey protein isolate product with a more desirable amino acid profile. Essentially this creates a higher biological value and a better conversation rate within the body. It's also the most expensive.
From a practical product review perspective, the smaller the pore size used in the filtration process, the more refined the end product and additionally the more expensive the product will cost. For example products that undergo nanofiltration are more expensive that those that undergo ultrafiltration or microfiltration.
The main advantage of cross-flow filtration over ion exchange filtration is that the amino acids that make up whey protein are preserved in their natural form with the highest biological value resulting in a product with a high conversion to muscle mass. The disadvantage is that they will generally be accompanied by a slightly higher percentage of fat and lactose (although in the whole scheme of things this is normally is a negligible amount).
Overall whey protein isolate products have the highest biological value of all whey protein products, meaning that they produce the highest conversion into the making of structural body proteins and muscle mass. The type and the degree of filtration will ultimately determine the biological value of the product which is then normally reflected in the price.
Benefits of Whey Protein Isolate (WPI)
There are a few reasons why people are willing to spend a little more money and invest in WPI over the cheaper WPC products.
The main advantage of WPI products is that they deliver a good serving of whey protein without the associated carbohydrates or fat, which is most beneficial for those looking to increase/preserve lean muscle mass without gaining unwanted fat or weight.
Whey protein isolate products have the highest biological value of all proteins on the market, maximizing the efficiency in which the protein is converted within the body and reducing the amount of waste.
Additionally most WPI products are around 90% protein, delivering around 27g of protein per 30g serve. Most research suggests that we need to be aiming for at least 25g of protein per meal (particularly after a workout) to have the most anabolic (muscle growth) effect.
During the filtration process of WPI products the majority of carbohydrate has been removed, reducing the amount of lactose (normally to less than 1%) and hence reducing the risk of associated lactose related side effects (such as gastric upset), which are occasionally reported among WPC users, in particular those with those with lactose intolerance. Whilst WPI products are generally considered safer for people who experience gastric upset with whey protein related products, Hydrolysed Whey Protein Isolate (HWPI) products are most easily digested and therefore are the best option for people who experience gastric related symptoms.
Disadvantages and potential side effects of Whey Protein Isolate (WPI)
One disadvantage to WPI is that even with the lactose removed some people are still susceptible to gastric upset with WPI products due to the long chain nature of some of the amino acids (also present in WPC) that require intense digestion. For this reason Hydrolysed Whey Protein Isolate (HWPI) products were created to help moderate this digestion process and reduce the risk. During the hydrolysis process of HWPI, long-chain amino acids are pre-digested by enzymes such that the end product is much easier for the human body to digest and as a result there is a significant reduction in the risk of side effects.
Given that WPI and HWPI products have to go through a process of refinement, this adds to the manufacturing costs and hence you will pay more at the point of sale. Putting things in perspective however you will find that most WPI and HWPI products deliver quality protein for less than $3 per serve which is still cheaper and more convenient that cooking a meal of lean meat and eggs.
Our best advice is that once you're sure that you're committed to your training and you find a product that you like, buy in bulk (3kg or more) as it works out a lot cheaper in the long run. Alternatively go halves with a mate.
How to Choose a Whey Protein Product?
Don't get sucked into buying the product with the most protein thinking it is the best, the amino acid profile (the makeup of the whey protein) is what determines the biological value not just the amount of protein. This will be reviewed in more detail in the future, in the short term you simply need to understand the following generalisation
Whey Protein Concentrate (WPC) - cheapest, most natural and complete form of whey protein. Comes with the highest percentage of fat and carbohydrate (lactose) and therefore takes longer to digest and there is a greater chance of gastric upset and bloating. Recommended for - beginner to moderate athletes and those looking to gain weight who otherwise have no trouble digesting dairy products.
Whey Protein Isolate (WPI) - greater percentage of protein per serve (less fat and carbohydrate), has the highest biological value (conversion of protein in the body) and the best overall effect on muscle growth. More expensive then WPC but cheaper then HWP. Recommended for - moderate to advanced athletes (majority of gym users), who wish to focus on muscle growth and recovery (not to be confused with weight gain) and/or those who are partially susceptible to dairy related symptoms (eg bloating, gastric upset).
Hydrolysed Whey Protein (HWP) - high protein percentage, absorbed the quickest, enabling quicker muscle recovery (really desirable for heavy trainers) with the lowest chance of side effects. It is the most expensive. Recommended for - advance athletes with high training volumes who need quicker recovery. Additionally is ideal for those who are very susceptible to dairy related symptoms (eg lactose intolerant).
Realated Whey Protein Articles
Learn about the benefits of Whey Protein
Learn more about Whey Protein Concentrate
Learn more about Hydrolysed Whey Protein (HWP and HWPI)
Learn more about Whey Protein Blends (products that contain a combination of WPC with WPI or HWPI)
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