Does Milk Contain Protein

In this brief article, we will be answering the question “does milk contain protein?”, and will be sharing with you the various benefits of milk along with its nutritional profile.

Does Milk Contain Protein?

Yes, milk contains proteins and is widely hailed as a complete source of proteins, in that it naturally contains all nine of the essential amino acids required by the body to function optimally.

Casein and whey are the main proteins found in milk. Casein comprises about 80 percent (29.5 g/L) of the total protein in bovine milk, whereas whey protein comprises about 20 percent (6.3 g/L). The amino acid profile is quite different between the two fractions: Whey is especially rich in branched chain amino acids, i.e., leucine, isoleucine, and valine as well as lysine, whereas casein has a higher proportion of histidine, methionine, and phenylalanine (1).

What Are The Benefits of Milk Proteins?

The benefits of milk proteins are to provide health, depending on the type of milk protein. Protein is the most fundamental component of tissues in animals and humans and is essential for regulating various important functions of the body, such as cell repair, growth and development, and immune system maintenance (2).

As mentioned, there are two main proteins present in milk – casein and whey protein, both of which are regarded as high-quality proteins. The main role attributed to caseins is mineral binding and their capacity as carriers, mainly for calcium and phosphorus. Total caseins can be divided in a-, b-, and k-caseins. They transport calcium and phosphorus, forming a coagulum and improving their digestibility in the stomach. Additionally, caseins give origin to several bioactive peptides that have shown benefits in human health, which include antibacterial, antiviral, antifungal, antioxidant, antihypertensive, antimicrobial, antithrombotic and immunomodulatory roles, in addition to improving absorption of other nutrients (1).

Whey protein constitutes the branched-chain amino acids valine, leucine, and isoleucine which are associated with various health benefits. Among the soluble protein fraction, lactoferrin, lactoperoxidase, and lysozyme are important antimicrobial agents, while lactoferrin together with b-lactoglobulin and a-lactoalbumin has shown suppressing action in tumor development. B-lactoglobulin is an important retinol carrier, while has shown fatty acid-binding action and antioxidant capacities, lactoferrin is a crucial element in iron absorption and in exerting antioxidant and anticarcinogenic effects (1). Branched-chain amino acids play a significant role in building muscle, generating fuel for exercise, and preventing muscle loss. This is why milk consumption has been linked to a reduced risk of age-related muscle loss.

Moreover, increased consumption of milk and its products has been associated with higher whole-body muscle mass and enhanced physical performance in aged adults. Several studies demonstrated the increase in body mass and muscle gain by supplementing the diet with milk proteins, including whey and casein (2).

Some more advantages of milk proteins include:

• improved muscle repair among athletes
• reduction in muscle damage
• enhanced overall strength
• reduced muscle soreness

Lastly, milk proteins are a natural alternative to the extremely processed protein drinks available for post-workout recovery and overall fitness.

Why should you consume protein?

You should consume protein because they provide you with amino acids. Proteins are structured molecules of bound amino acids. Amino acids that are supplied by the ingestion and further through digestion debranching of proteins and are precursors for the synthesis of enzymes, cells, and many others low-molecular weight substances (e.g., glutathione, creatine, nitric oxide, dopamine, serotonin, RNA and DNA) responsible for many important physiological functions of the human body (2).

Amino acids are a source of elements that are not synthesized in the body: nitrogen, hydrocarbon skeletons, and sulfur, which are essential for the body. These elements are not provided by other nutrients, such as carbohydrates and lipids. Thus, amino acids are essential for the health, growth, development, reproduction, lactation, and survival of organisms.

How Much Protein Should You Consume Daily?

According to the Dietary Reference Intake report for macronutrients, an adult with limited physical movement should consume  0.8 grams of protein per kilogram of body weight (0.36 grams per pound). To meet the functional needs such as promoting skeletal-muscle protein accretion and physical strength, dietary intake of 1.0, 1.3, and 1.6 g protein per kg BW per day is recommended for individuals with minimal, moderate, and intense physical activity, respectively (2).

This implies that an average sedentary man should consume approximately 56 grams of protein every day, whereas an average sedentary woman should consume approximately  46 grams of protein every day.

Which Milk Contains The Most Protein?

Dry milk contains the highest amount of protein.

Whole dry milk contains 6.32 grams of protein in a 100-gram serving and non-fat dry milk contains 36.16 grams of protein in a 100-gram serving.

However, the protein content drops when concentrated dry milk is rehydrated with water.

Which Milk Is The Best Source of Protein (And Overall Best)?

The best source of milk protein is cow’s milk, which is also the most widely consumed, and I recommend dairy milk. Both animal and plant products are excellent sources of select vitamins, but several lines of evidence show that animal-source protein, such as milk protein, has a greater nutritional value than plant-source protein to sustain skeletal-muscle mass (2). Cow milk is also rich in B vitamins, calcium, and various minerals. 

Cow milk is routinely fortified with vitamins A and D to make it even more nutritious, especially for growing children.

Contrary to popular belief, full-fat cow milk does not have any health risks and while people often opt for skim or low-fat milk, there is no scientific proof that these varieties are healthier or more nutritious than full-fat milk. There is no strong evidence demonstrating hazards from whole milk consumption due to specific and diverse metabolic effects of the saturated fatty acids found in milk fat fraction (1).

What Is The Nutritional Profile Of Milk?

A single cup (244 grams) of whole cow’s milk contains (1):

• 146 calories
• 8 grams of protein
• 8 grams of fat
• 28 percent of the Recommended Daily Allowance of calcium
• 24 percent of the RDA of Vitamin D
• 26 percent of the RDA of Riboflavin (B2)

• 18 percent of the RDA of Vitamin B12
• 10 percent of the RDA of Potassium
• 22 percent of the RDA of Phosphorus
• 13 percent of the RDA of Selenium

Milk contains a plethora of minerals and vitamins, especially the nutrients that are commonly under-consumed in many populations. These include potassium, calcium, vitamin B12, and vitamin D. Milk also provides good amounts of vitamin A and thiamine (vitamin B1) as well as magnesium and zinc.

Milk is also an exceptional source of fatty acids including conjugated linoleic acid (CLA) and omega-3’s. These fatty acids are associated with reducing the risk of heart disease and diabetes. 

Does The Nutritional Profile Of Milk Vary?

Yes, the nutritional profile of milk varies, based on factors such as fat content, and the diet and treatment of the animal it comes from.

For instance, cows that mainly consume grass and organic feed produce milk that is significantly rich in conjugated linoleic acid, omega-3 fatty acids, and beneficial antioxidants including vitamin E and beta-carotene that alleviate inflammation and prevent cell damage from oxidative stress.

Conclusion

In this brief article, we answered the question “does milk contain protein?” and shared with you the various benefits of milk along with its nutritional profile.

If you have any questions and comments please let us know.

References

(1). Pereira, Paula C. Milk nutritional composition and its role in human health. Nutrition, 2014, 30, 619-627.

(2). Wu, Guoyao. Dietary protein intake and human health. Food func, 2016, 7, 1251-1265.