Milk Protein Isolate

Not many people are familiar with milk protein isolate, or frequently confuse it with other milk protein products such as whey- or milk- protein concentrate.

However, it can be found on many product labels if you take the time to look. Below we’ll take a look at what exactly milk protein isolate is and how it affects our bodies.

What Is It?

Milk protein isolate is a powder resulting from the processing of milk to remove liquids and non-protein components [1], leaving you with an isolate that is at minimum 90 percent protein.

The protein in milk protein isolate exists in the same ratios as it does in milk, meaning the protein content is about 80 percent casein and 20 percent whey proteins. This protein powder can be used as an ingredient in popular meal replacement shakes, bars, and more.

What Is Its Biological Role?

In general, milk protein isolate is absorbed the same as any other protein we ingest. The specifics vary depending on the type of protein ingest, but before we can delve into that it is important to understand the basics. When we consume protein [2], the acids in the stomach go to work breaking them up into their constituents.

Even though we talk about protein as if it is a single thing, it is not. Proteins are different depending upon their source, and are actually composed of smaller building blocks called peptides, which themselves are composed of even tinier units called amino acids. So, the acids in the stomach separate the proteins into smaller peptides, and then those peptides are eventually reduced to amino acids in the small intestine.

Amino acids are what is absorbed into the body via the small intestine, and what can act on our cells to stimulate muscle growth and muscle repair, control our blood glucose levels, etc. The major differences in how different types of protein affect us comes down to how complicated their structure is, and how long it takes them to be broken down into amino acids and absorbed by the body.

Whey and casein protein (the proteins found in milk protein isolate) are both known to be particularly effective at assisting in the repair and growth of muscles.

How Does It Help Bodybuilders and People Who Work Out?

Whey protein hits the system very quickly, but because they contain a fair amount of sulfur are also flushed from the body rather quickly. This type of protein is most effective for short term needs like recovery after a workout, or a meal replacement that doesn’t need to keep you full for more than a few hours.

Casein protein, on the other hand, takes a little bit longer to be released into the body but also sticks around for quite a while. Casein protein has been shown to remain in our bodies for up to 7 hours. For this reason, many fitness enthusiasts choose to consume protein drinks high in casein before sleep.

Sleep is an important time for muscle growth and repair, and the relatively long life of casein protein in our bodies boosts the effectiveness of this process.

What Foods Contain It?

Milk protein isolate is added to a variety of foods. These include protein powders, protein bars, yogurts, sports drinks meant for exercise recovery, and more.

How Much Of It Do You Need?

There is no officially recognized daily allowance for milk protein isolate. If you should choose to incorporate milk protein isolate into your diet as part of your daily total protein needs, your total protein recommendation would be based upon activity level and caloric intake.

Generally, most adults need about .05g of protein per pound of body weight. If you are very active and require more calories to provide adequate fuel, this amount may increase to .08g or more.

Are There Risks Associated With Consuming Too Much Of It?

The risks associated with excessive consumption of milk protein isolate [3] are not so much because of the type of protein itself, but of excess protein consumption in general. If you consume too much protein too quickly or over an extended period of time, you risk permanently damaging your kidneys as they struggle to filter the proteins wastes out of your system.

Are There Risks Associated With Consuming Too Little Of It?

Similarly to excess consumption, avoiding milk protein isolate is only negative if you do not get enough protein from other sources. Not consuming milk protein will not hurt you, but protein deficiency in general will cause fatigue, weakness, and other health complications that become more severe over time.

It may seem cliché, but knowledge really is power. Knowing what this ingredient is and how it affects your body will empower you to take the reins of your own nutrition to ensure you feel your best.


[1] American Dairy Products Institute. Dry Milks-Milk Protein Isolate., 2014.

[2] Carson, Tara. Five Stages of Protein Digestion., 2013.

[3] Taylor, Marygrace. 5 Dangerous Things That Happen When You Eat Way Too Much Protein., 2015.