Whey Protein 101: Nutrition Facts, Benefits, and Drawbacks

Whey protein is a type of protein found within dairy products.

The popularity of whey has increased rapidly over the past decade, and it is a common source of dietary protein and a valued sports supplement.

However, what nutritional benefits does whey protein offer?

This article examines the nutrition profile, potential benefits, and drawbacks of whey protein.

What Is Whey Protein?

Whey is a protein-rich form of dairy, and it is a by-product of the cheesemaking process.

After making cheese, the producers are left with a watery liquid called whey.

At this stage, the liquid only needs drying to become whey protein powder.

Mixing whey with either milk or water provides a convenient and highly portable drink with high protein content. For this reason, whey enjoys popularity as a post-exercise drink.

Forms of Whey Protein

There are several different types of whey protein, but the most predominant varieties are:

• Whey protein concentrate (WPC): in addition to its high protein content, whey protein concentrate also contains small amounts of carbohydrate and fat. The protein composition of whey protein concentrate is typically 75-89%  (1).
• Whey protein isolate (WPI): this variety of whey undergoes further processing to remove the lactose and milk fat. As a result, it offers a more concentrated source of protein, and it is typically 90% + protein by weight (2).
• Whey protein hydrolysate: a type of whey which has been partially “pre-digested” by either heat or enzymatic treatments. These treatments make it easier to digest the whey protein (3).

Nutrition Facts

According to the USDA FoodData Central database, a typical serving (32 g) of whey protein concentrate offers the following nutrients (1):

Vitamins

Despite whey’s reputation of being an isolated source of protein, it also offers a good range of vitamins.

Per serving, whey offers the following vitamin values:

• Riboflavin (B2): 50 % DV
• Thiamin (B1): 15.8 % DV
• Niacin (B3): 2.3 % DV
• Pantothenic acid (B5): 35.4 % DV
• Vitamin B6: 11.2 % DV
• Vitamin B12: 32.5 % DV
• Choline: 13 % DV
• Folate: 2.6 % DV

As shown in the above list, whey protein is an excellent source of B vitamins.

Minerals

In addition to its vitamin profile, whey protein also offers a good range of minerals.

One serving offers the following essential mineral values:

• Phosphorus: 33.8% DV
• Zinc: 18% DV
• Selenium: 15.5% DV
• Magnesium: 14.9% DV
• Calcium: 11.5% DV
• Potassium: 3.4% DV
• Copper: 2.2% DV
• Sodium: 2.2% DV
• Iron: 2% DV

As the mineral profile demonstrates, whey is particularly high in phosphorus, zinc, selenium, and magnesium.

Benefits

There are several potential benefits of consuming whey protein.

In this section, we will look at some of the general benefits and examine what recent scientific research has demonstrated.

Whey Protein Has An Excellent Amino Acid Profile

Since whey is such a concentrated source of protein, it offers an impressive amino acid profile.

First of all, whey contains all nine essential amino acids in large quantities, and it is also rich in non-essential amino acids.

Notably, a recent study showed that whey protein has a higher content of essential amino acids than any other animal-based protein. The following table shows the amino acid profile of whey protein per 100 grams (4):

Note: this study did not measure the values for tryptophan, aspartic acid, asparagine, and glutamine.

Furthermore, one study compared the full amino acid profiles of fifteen whey protein samples from different manufacturers. The results of this research are available here.

Promotes Lean Muscle Gain and Strength

Research has demonstrated that whey protein can promote lean muscle gain.

For instance, in a double-blind randomized controlled trial, thirty-six participants took either 40 grams of whey protein per day, a combination of whey and casein, or a whey and BCAA supplement (5).

After ten weeks, all groups, including the whey protein group, had achieved gains in lean muscle mass and significant strength increases.

Additionally, a randomized controlled trial featuring 81 healthy older female participants demonstrated that daily whey protein intake (providing 22.3g of protein) increased skeletal muscle mass over a 24-week program (6).

However, it is worth pointing out that all dietary protein has this effect of promoting muscle gain, so it is not a unique benefit of whey.

In other words, eating more protein, whether from meat, dairy, fish, or any other protein source, should have a similar effect.

Whey Protein May Also Enhance Muscle Protein Synthesis

Recent research suggests that whey protein can boost muscle protein synthesis. For those unaware, muscle protein synthesis is the process through which we produce protein to recover from exercise-induced muscle damage (7).

The rate of muscle protein synthesis plays a vital role in building muscle. For example, if we wish to gain muscle, the rate of muscle protein synthesis needs to be higher than the speed of muscle protein breakdown (8).

On this note, several studies suggest that whey protein intake can speed up the rate of muscle protein synthesis (9, 10, 11).

Convenient Source of Protein

One of the major benefits of whey protein is how easy to use (and portable) it is.

For instance, it is easy to take some whey protein to work, school, or the gym in a flask or bottle. From here, it only requires mixing with water to make a convenient protein-rich drink.

While food sources of protein offer a more satisfying experience, whey is hard to beat for convenience. This convenience may also extend to specific groups of older adults.

In this regard, some older adults may suffer from digestive problems or otherwise find it challenging to consume enough protein. Research in such population groups shows that whey protein can help older adults to rebuild lost muscle.

For example, a randomized controlled trial analyzed the effects of a diet supplemented with whey protein in adults between the ages of 65 and 80.

This trial found that whey protein intake increased protein synthesis and led to increases in lean muscle mass even during periods of energy restriction (12).

May Increase Glutathione Levels

Glutathione, also known as the body’s “master antioxidant,” helps to protect the body against oxidative damage. This important compound plays a role in every cell within the human body (13, 14).

The amino acids cysteine and glutamate are precursors for the production of glutathione, and whey protein is rich in both these amino acids (15, 16).

Further to this, numerous studies—including randomized controlled trials—have shown that whey protein can boost the rate at which glutathione is synthesized as well as increase blood levels of the compound (17, 18, 19, 20).

In a mouse study, feeding mice a whey-rich diet between the ages of 17 months and 20 months enhanced glutathione levels in the heart and liver. Interestingly, these mice also enjoyed increased longevity compared to control mice fed a standard diet (21).

Although this study is interesting, we cannot apply the results of an animal study to humans. That said, studies do show that increasing glutathione levels via whey protein supplementation can have benefits in humans.

For example, in a randomized, double-blind controlled trial, whey protein supplementation improved nutritional status and glutathione levels in cancer patients undergoing chemotherapy. Tracked health markers also showed that these patients exhibited improved immune function (22).

Preserves Muscle Mass During Weight Loss

During weight loss, it is important to try to preserve lean muscle mass. To put it another way, we want to lose fat rather than muscle.

On the negative side, the process of losing weight is highly catabolic, which means that dieting promotes the breakdown (rather than building) of muscle tissue (23).

Research shows that maintaining high protein intake is one of the best methods for preserving lean muscle mass during periods of weight loss (24, 25).

Since whey protein is the most concentrated dietary source of protein, it can be beneficial for this purpose.

In a randomized controlled trial, participants allocated to a high-protein whey-based supplement lost the same weight as a placebo group during a low-calorie diet. However, the whey group preserved muscle mass while the placebo group did not (26).

A further double-blind, randomized controlled trial found that 27 grams of whey protein twice-daily could preserve lean muscle mass during a diet. In this study, supplementing with whey protein resolved declining rates of muscle protein synthesis during weight loss on a hypocaloric diet (27).

Contains Immunoglobulins

Further to its overall nutrition profile, whey contains various proteins called immunoglobulins, which are also known as antibodies.

Immunoglobulins play a beneficial role in immune response. We can refer to those found within whey protein as bovine immunoglobulins (28).

Research on these bovine immunoglobulins is at a relatively early stage, but initial studies suggest they may have potential benefits for human health.

This research has found that bovine immunoglobulins may:

• Help to lower levels of inflammation (29).
• Have benefits for treating irritable bowel syndrome and lowering the frequency of symptoms (30).
• Improve intestinal barrier function (31).
• Potentially have anti-bacterial properties (32).

Whey protein consists of approximately 8% bovine immunoglobulins by weight (33).

Mixed Research Suggests Whey Might Improve Satiety Levels

A diet that suppresses hunger and food cravings by enhancing satiety ensures a greater chance of long-term success (34, 35).

Satiety refers to the feeling of being satisfied after eating and experiencing a lack of hunger.

In this regard, several human trials have indicated that whey protein intake led to decreased hunger, reduced appetite, and lower subsequent energy intake throughout the day (36, 37, 38).

However, research on whey protein and satiety is inconsistent. For instance, other trials show a lack of evidence for satiety-enhancing effects (39, 40).

Further to this, one study even found that skim milk reduced subsequent calorie intake more effectively than whey (41).

These trials are all relatively small and feature 15-20 participants, which could be one reason why the results vary so much. Better powered, more extensive research may provide more valuable insights in this area.

Whey Is Highly Bioavailable

A critical but often neglected point about dietary protein is that source matters.

For example, it is not only the quantity of protein that is important, but also the amino acid profile, and how bioavailable those amino acids are.

Currently, DIAAS (digestible indispensable amino acid score) is thought to be the best measurement of the protein quality of a specific food (42).

DIAAS measures the total digestibility of each amino acid in a protein, so it is very accurate.

According to DIAAS, the higher the rating, the higher the protein quality of a specific food.

As shown by studies into the DIAAS rating of different foods, whey protein offers one of the highest quality sources of protein. The list below shows how the protein quality of whey compares to several other protein options (43):

• Milk protein concentrate: 1.18
• Whole milk: 1.14
• Egg: 1.13
• Whey protein isolate: 1.09
• Chicken breast: 1.08
• Soy protein isolate: 0.90
• Chickpeas: 0.83
• Pea protein concentrate: 0.82

Potential Drawbacks

Although whey protein has an impressive nutrition profile and offers some good benefits, there are also several drawbacks to consider.

Taste

Pure unflavored whey protein has a slightly bitter, sour, and even chalky flavor.

Since whey is milk without the sugar and fat, it does not taste particularly nice.

While some people may be able to drink whey in its pure form, others may dislike the flavor too much. In this case, there are two ways to get around the taste:

• Buy a flavored whey product: it is easy to find flavored and sweetened whey protein. These products generally use sweeteners such as aspartame or stevia, and flavors such as chocolate and strawberry.
• Blend unflavored whey with some fruit: blending unflavored whey with some water and fruit can provide a more naturally flavored whey shake. Frozen berries work well for this purpose and result in a thick and fruity drink.

Allergies

Compared to other dairy products, whey is much less likely to trigger sensitivities or food allergies. The reason for this is because it only contains small amounts of lactose.

However, research shows that whey protein concentrate may still contain enough lactose to cause problems for individuals with severe lactose intolerance. In this case, replacing whey concentrate with isolate may be a solution since whey protein isolate is virtually free of lactose (44).

That said, there are also rare cases of cow’s milk allergy, which is unrelated to the lactose content of a food.

Researchers have shown that people with cow’s milk allergy are also sensitive to the proteins alpha-lactalbumin and beta-lactoglobulin. Unfortunately, these proteins are present in significant amounts in whey (45).

Which Groups Might Benefit From Whey Protein?

There are several different groups of people who may benefit from using whey protein.

These include:

• Athletes, bodybuilders, and sports professionals: whey is a convenient source of protein for those who need to consume higher amounts of protein than the average person.
• People trying to increase protein intake: for those who are trying to improve their protein intake, whey offers a large amount of extra protein for very few calories.
• Older adults who have trouble consuming enough protein: drinking some whey protein is an easy way to get protein into the diet for those who need it. Studies show that whey protein can help preserve muscle mass, strength, and improve the quality of life in older adults who have lost muscle tissue (46).

Which is the Best Whey Protein Product?

Generally speaking, most pure whey protein products use similar ingredients and are not significantly different from each other.

However, an independent laboratory that tests various supplements called Labdoor has published a ranking guide of popular protein powders.

These rankings take the purity, nutritional value, ingredient safety, and label accuracy of the different whey protein products into account.

Aside from this, taste and value should be the key deciders for similar products.

Final Thoughts

Overall, there are numerous reasons why whey protein can play a beneficial role in our diet.

It is an excellent source of protein, relatively affordable, and it provides a useful range of vitamins and minerals.

Since whey protein is also highly convenient and easy to drink, it can be a useful tool in the nutritional strategy for many different people.

However, it is not an essential part of the diet, and other sources of protein can offer several of the same benefits.