A Primer on Protein Powders

Walk into any dietary supplement store and you’re likely to see a whole wall filled with nothing but protein powders. It seems like there are more varieties than the number of pounds that The Rock can bench press. While many people might grab a protein shake once in a while before or after a gym session, how much do we really know about them? How are they made? How does whey protein stack up against pea protein? And do we really need to use them at all?


Protein powders are – you guessed it – powdered forms of protein made from animal foods like milk and eggs or plant sources like soy, peas, rice and hemp. They come in a few different forms: whole protein powders, concentrates, isolates and hydrolysates.

Let’s start with whole protein powders, of which whey is a popular example. In its original form, whey is the watery liquid part of milk that separates off during cheese or yogurt production. From this liquid, whey proteins are separated and purified to create whey protein powder. Whey protein in this form is a mixture of protein, the milk sugar lactose, vitamins, minerals and a small amount of milk fat. While whey protein powder in this form is used as an ingredient in many kinds of food products, you won’t often find plant-based proteins in anything other than the more processed versions we’re about to describe.

Protein concentrates are made by extracting protein from the starting material (such as liquid whey) through the use of heat or enzymes. This removes water, some of the lactose and minerals. Concentrates tend to have a lower percentage of protein as compared to isolates, because they still contain some carbohydrates and fat.

With protein concentrations of 90 percent or higher, isolates are the purest form of protein powders. To make a protein isolate, components like carbohydrates, fats and minerals are removed during processing. In other words, protein is isolated. If the starting material is whey then lactose is also removed, meaning that even those who are lactose intolerant can generally consume whey protein isolates without getting an upset stomach. Since carbohydrates are removed, plant-based protein powders labeled as “isolates” generally won’t have any dietary fiber unless it’s added after processing.

The protein in concentrates and isolates is composed of long chains of amino acids, which are the building blocks of protein. In order to absorb them into our bloodstream, enzymes in our digestive system have to break the bonds between amino acids to create smaller chains and individual amino acids. Protein hydrolysate powders have done much of this work for us, containing “pre-digested” proteins made by treating with heat, acid or enzymes to speed up absorption.


Whey Protein

Milk contains two major forms of protein: whey and casein. As cheese and yogurt are made, these proteins separate into two layers. Whey collects in the watery liquid that’s strained out. The top, solid portion contains casein. Whey and other animal-based protein powders are widely used because they are fairly tasteless and contain all nine essential amino acids. Our bodies cannot make all amino acids. Therefore, it is important that we get them through complete protein sources, like whey. This is necessary for maintaining normal body functions like the ability to build and maintain muscle.

Unlike casein, whey protein is rapidly digested and is associated with greater feelings of fullness. This, along with its low fat and sugar content, can lead to reduced calorie intake – an added benefit for weight-conscious people.

Casein Protein

Casein accounts for most of the protein in milk-containing products. It is digested slower than whey and serves as an excellent complete protein and calcium source. Like whey, casein alone does not have a strong taste which makes it easy to offer in various flavors like vanilla, chocolate or cookies and cream.

Collagen Protein

Collagen naturally occurs in our bodies as a part of connective tissue. It aids in attaching muscle to bone, forms joints and is a structural component of skin. When taken as a supplement, collagen is digested into smaller chains of amino acids and is used according to our bodies’ needs. This means that sometimes the eight out of nine amino acids from collagen are used to promote healing, and other times they may encourage skin elasticity.

Egg White Protein

You may have seen athletes in old movies drinking raw eggs for additional protein (think Sylvester Stallone in Rocky). Today, we still use eggs to get protein, but with less risk of salmonella poisoning. Egg white protein powders are sold as an easily digestible, complete protein source. As the name suggests, these low-calorie supplements are made from dehydrated egg whites. During production, pasteurization (rapidly heating to high temperatures) is used to reduce bacteria content and inactivate avidin, a protein in egg whites that can lead to a deficiency in nutrients required for healthy hair, skin and nails.

Plant-based Proteins

Newer to the protein powder scene are several plant-based options. A number of protein-containing plants, including soy, pea, hemp and brown rice, have been used to diversify our choices in the protein powder aisle. Of these, soy is perhaps the most popular. Like animal proteins, soy contains all nine essential amino acids in adequate amounts and is considered a high-quality protein. Others, like brown rice protein, are incomplete and fairly new. They have not been extensively studied to make definitive recommendations regarding their nutritional quality.


Protein powders can be an option for people who need help increasing their protein intake in cases where eating whole, solid foods is difficult or inconvenient (I know I don’t like to exercise right after a full meal!). They have also been shown to improve physical performance and reduce recovery timeafter an intense workout. However, most of us aren’t bodybuilders or elite athletes, so having a protein shake before or after a workout might not be necessary. They could easily contain more calories than we burned during our gym session!

It may be helpful to consult with a registered dietitian before starting any new protein supplement. Dietary supplements are not regulated by the U.S. Food and Drug Administration, which means that what you see on the label may not always be what you get in the product.

Remember, there are plenty of whole foods that offer healthy doses of protein. Foods like legumes, eggs, dairy, fish and meat are great ways to include protein in a healthy eating pattern.

This blog was written by Casey Evans, 2018 Sylvia Rowe Fellow, with contributions for Allison Webster, PhD, RD.