Whey protein is among the best studied supplements in the world, and for good reason.
It has a very high nutritional value, and scientific studies have revealed numerous health benefits.
Here are 10 health benefits of whey protein that are supported by human studies.
1. Whey is an Excellent Source of High-Quality Protein
Whey protein is the protein fraction of whey, which is a liquid that separates from milk during cheese production.
It is a complete, high-quality protein, containing all of the essential amino acids.
In addition, it is very digestible, absorbed from the gut quickly compared to other types of protein ().
These qualities make it one of the best dietary sources of protein available.
There are three main types of whey protein powder, concentrate (WPC), isolate (WPI), and hydrolysate (WPH).
Concentrate is the most common type, and is also the cheapest.
As a dietary supplement, whey protein is widely popular among bodybuilders, athletes, and others who want additional protein in their diet.
Bottom Line: Whey protein has a very high nutritional value, and is one of the best dietary sources of high-quality protein. It is highly digestible, and absorbed quickly compared to other proteins.
2. Whey Protein Promotes Muscle Growth
Muscle mass naturally declines with age.
This usually leads to fat gain and raises the risk of many chronic diseases.
However, this adverse change in body composition can be partly slowed, prevented, or reversed with a combination of strength training and adequate diet.
Strength training coupled with the consumption of high-protein foods or protein supplements has been shown to be an effective preventive strategy ().
Particularly effective are high-quality protein sources, such as whey, which is rich in a branched-chain amino acid called leucine.
Leucine is the most growth-promoting (anabolic) of the amino acids ().
For this reason, whey protein is effective for the prevention of age-related muscle loss, as well as for improved strength and a better-looking body ().
For muscle growth, whey protein has been shown to be slightly better compared to other types of protein, such as casein or soy (, , ).
However, unless your diet is already lacking in protein, supplements probably won't make a big difference.
Bottom Line: Whey protein is excellent for promoting muscle growth and maintenance when coupled with strength training.
3. Whey Protein May Lower Blood Pressure
Abnormally high blood pressure (hypertension) is one of the leading risk factors for heart disease.
Numerous studies have linked the consumption of dairy products with reduced blood pressure (, , , ).
This effect has been attributed to a family of bioactive peptides in dairy, so-called "angiotensin-converting-enzyme inhibitors" (ACE-inhibitors) (, , ).
In whey proteins, the ACE-inhibitors are called lactokinins (). Several animal studies have demonstrated their beneficial effects on blood pressure (, ).
A limited number of human studies have investigated the effect of whey proteins on blood pressure, and many experts consider the evidence to be inconclusive.
One study in overweight individuals showed that whey protein supplementation, 54 g/day for 12 weeks, lowered systolic blood pressure by 4%. Other milk proteins (casein) had similar effects ().
This is supported by another study that found significant effects when participants were given whey protein concentrate (22 g/day) for 6 weeks.
However, blood pressure decreased only in those that had high or slightly elevated blood pressure to begin with ().
No significant effects on blood pressure were detected in a study that used much lower amounts of whey protein (less than 3.25 g/day) mixed in a milk drink ().
Bottom Line: Whey proteins may lower blood pressure in people with elevated blood pressure. This is due to bioactive peptides called lactokinins.
4. Whey Protein May Help Treat Type 2 Diabetes
Type 2 diabetes is a chronic disease characterized by high blood sugar and impaired function of insulin.
Insulin is a hormone that is supposed to stimulate the uptake of blood sugar into cells, keeping it within healthy limits.
Whey protein has been found to be effective at moderating blood sugar, increasing both the levels of insulin and the sensitivity to its effects (, , , ).
These properties of whey protein may even be comparable to those of diabetic drugs, such as sulfonylurea ().
As a result, whey protein can be effectively used as a supplementary treatment for type 2 diabetes.
Taking a whey protein supplement before or with a high-carb meal has been shown to moderate blood sugar in both healthy people and type 2 diabetics ().
Bottom Line: Whey protein is effective at moderating blood sugar levels, especially when taken before or with high-carb meals. It may be particularly useful for people with type 2 diabetes.
5. Whey Protein May Help Reduce Inflammation
Inflammation is part of the body's response to damage. Short-term inflammation is beneficial, but under certain circumstances it may become chronic.
Chronic inflammation can be harmful, and is a risk factor for many diseases. It may reflect underlying health problems or bad lifestyle habits.
A large review study found that high doses of whey protein supplements significantly reduced C-reactive protein (CRP), a key marker of inflammation in the body ().
Bottom Line: High doses of whey protein have been shown to reduce blood levels of C-reactive protein, indicating that it can help reduce inflammation.
6. Whey Protein May Be Beneficial for Inflammatory Bowel Disease
Inflammatory bowel disease is a condition characterized by chronic inflammation in the lining of the digestive tract.
It is a collective term for Crohn's disease and ulcerative colitis.
In both rodents and humans, whey protein supplementation has been found to have beneficial effects on inflammatory bowel disease (, ).
However, the available evidence is weak and further studies are needed before any strong claims can be made.
Bottom Line: Whey protein supplements may have beneficial effects on inflammatory bowel disease.
7. Whey Protein May Enhance the Body's Antioxidant Defenses
Antioxidants are substances that act against oxidation in the body, reducing oxidative stress and cutting the risk of various chronic diseases.
One of the most important antioxidants in humans is glutathione.
Unlike most antioxidants we get from the diet, glutathione is produced by the body.
In the body, glutathione production depends on the supply of several amino acids, such as cysteine, which is sometimes of limited supply.
For this reason, high-cysteine foods, such as whey protein, may boost the body's natural antioxidant defenses (, ).
A number of studies in both humans and rodents have found that whey proteins may reduce oxidative stress and increase levels of glutathione (, , , ).
Bottom Line: Whey protein supplementation may strengthen the body's antioxidant defenses by promoting the formation of glutathione, one of the body's main antioxidants.
8. Whey Protein May Have Beneficial Effects on Blood Fats
High cholesterol, especially , is a risk factor for heart disease.
In one study in overweight individuals, 54 grams of whey protein per day, for 12 weeks, led to a significant reduction in total and LDL (the "bad") cholesterol ().
Other studies did not find similar effects on blood cholesterol (, ), but the lack of effect might be due to differences in study design.
Further studies are needed before any conclusions can be made.
Bottom Line: Long-term, high-dose whey protein supplementation may lower cholesterol levels. The evidence is very limited at this point.
9. Whey Protein is Highly Satiating (Filling), Which May Help Reduce Hunger
Satiety is a term used to describe the feeling of fullness we experience after eating a meal.
It is the opposite of appetite and hunger, and should suppress cravings for food and the desire to eat.
Protein is by far the most filling of the three macronutrients ().
However, not all proteins have the same effect on satiety. Whey protein appears to be more satiating than other types of protein, such as casein and soy (, ).
These properties make it particularly useful for those who need to eat fewer calories and lose weight.
Bottom Line: Whey protein is very satiating (filling), even more so than other types of protein. This makes it a useful addition to a weight loss diet.
10. Whey Protein Can Help You Lose Weight
Increased consumption of protein is a well-known weight loss strategy (, , ).
- Suppressing appetite, leading to reduced calorie intake ().
- Boosting metabolism, helping you burn more calories (, ).
- Helping to maintain muscle mass when losing weight ().
Whey protein has been shown to be particularly effective, and may have a superior effect on fat burning and satiety compared to other protein types (, , , , ).
Bottom Line: Eating plenty of protein is a very effective way to lose weight, and some studies show that whey protein may have even greater effects than other types of protein.
Side Effects, Dosage, and How to Use It
Whey protein is very easy to incorporate into the diet.
It is sold as a powder that can be added to smoothies, yogurts, or simply mixed with water or milk.
25-50 grams per day (1-2 scoops) is a commonly recommended dosage, but make sure to follow the dosage instructions on the packaging.
Keep in mind that taking too much protein is useless. The body can only utilize a limited amount of protein at a given time.
Excessive consumption may also cause digestive problems, such as nausea, pain, bloating, cramping, flatulence, and diarrhea.
However, moderate consumption of whey protein supplements is well tolerated by most people, with a few exceptions.
If you are lactose intolerant, whey protein hydrolysate or isolate may be more suitable than concentrate. If you have ever had liver or kidney problems, then consult with a doctor before taking a protein supplement.
At the end of the day, whey protein is not just a convenient way to boost your protein intake, it may have some powerful health benefits as well.