what is casein

Understanding Casein and Micellar Casein

By Ladder

As far as protein goes, any high-quality complete protein is a great foundation for muscle gain, fat loss, and improved recovery.

But, if you're looking for more than just the basics, combining a couple of different sources of protein might help give your body an additional boost.

If you dig into the research about protein, studies suggest that a special combination of whey and casein protein might be the ultimate mix for optimal results.

In fact, when compared to carbs, the blend of whey protein and casein had greater benefits than carbs.

If you want to add casein to your diet, it's important to understand why this protein is oftentimes overlooked and might give your body exactly what it needs when combined with whey.

What Is Casein?

Casein protein comprises about 80 percent of all milk protein, with the remaining 20 percent being whey protein. Casein is a slow-releasing protein that has been shown to support muscle growth.

Casein is a complete animal protein, meaning it contains all the essential amino acids your body needs to function well, as well as important minerals such as calcium and phosphorus.

While casein is found in the milk of different animals, we mainly consume the one derived from cow's milk. One cup of reduced-fat (2%) milk contains approximately 8 grams of protein, the majority of which is from casein. Comparatively, cottage cheese contains around 25 grams of protein per cup, making dairy products a great source of casein.

Casein vs. Whey

Casein and whey have different chemical profiles, and they are extracted from milk in different ways. As milk is heated and enriched with different enzymes in the cheese-making process, the casein coagulates and forms curds that are made into cheese or added into dairy products, while whey separates into a liquid that can be washed, dried, and made into a powder.

To put it in simple terms: casein is the solid milk extract, and whey is the liquid part.

Although they are both complete proteins, casein and whey have different amino acid profiles as well as absorption rates. It has been shown that whey protein consumption promotes higher amounts of EAAs, including leucine, in the blood and, therefore, stimulates muscle protein synthesis to a greater extent than either casein or soy protein. Leucine, in particular, has been found to boost muscle protein synthesis.

Essential amino acids aren't produced by the body, and therefore, especially as an athlete, you do need to make sure to meet your daily EAA requirements. However, although whey protein has more of some EAAs, the main difference between casein and whey is in the rate of their absorption.

While whey protein is digested rapidly, casein has the ability to form a gel or a clot in the stomach, ensuring a sustained, slow release of AAs, usually lasting several hours.

Comparatively, studies show that whey protein increases leucine in the plasma almost immediately post-consumption. Whey ingestion stimulates protein synthesis by 68%, while protein synthesis after casein ingestion is at 31%.

The slow-releasing casein can, therefore, be used before bed as a long-acting support for muscle growth, while whey protein has more immediate benefits.

What Are the Benefits of Casein Protein?

Proteins, including casein, help support many important physiological functions.

Casein has relatively high levels of each EAA. Amino acids are incredibly beneficial as they provide the building blocks for protein, reduce protein catabolism (the breakdown of proteins), and enable muscle-building.

Casein is mainly found in dairy products. Yogurts and cottage cheese contain high levels of casein, so eating these foods is a good way to increase the percentage of casein within your daily protein intake. However, if you're looking to consume more than the average recommended amounts, as many athletes do, protein dietary supplements are a good way to go.

Due in part to its leucine content — and possibly its digestion rate — casein is extremely useful for long-term muscle building. What's more, when ingested at night, it supports muscle protein synthesis.

Researchers found that casein supplementation can lead to improved muscle strength and an increase in lean tissue. Casein has also been demonstrated to aid in fat loss, along with increasing lean gains when combined with a hypocaloric diet and exercise.

In terms of weight management, increasing the amount of casein in your diet may boost your energy expenditure (metabolism) and increase your base metabolic rate while improving satiety and making you feel fuller and less prone to food binges.

Not only can casein help with your fitness goals, help improve strength, and build muscle, but the bioactive peptides contained in casein could have great additional health benefits.

Are There Any Side Effects of Casein Protein?

Casein protein is generally safe to consume for healthy individuals. Some people may have a casein allergy or lactose intolerance, in which case, any foods or dietary supplements need to be carefully examined for ingredients. While casein and whey protein powders generally don't contain any lactose, they could still have trace amounts.

There does not appear to be any negative impact on kidney function in otherwise healthy individuals when following a high protein diet. However, those with compromised kidney function should seek medical advice.

What Is Micellar Casein?

Micellar casein is the purest form of casein there is. In milk, casein is contained within micelles, essentially solid particles floating in liquid.

Remember how we mentioned that casein takes a while to release amino acids? It's because it's found in these micelles, which have the ability to form a gel or a clot in the stomach and supply long-acting nutritional benefits.

What's the Difference Between Micellar Casein and Casein?

Micellar casein is the by-product of cheese-making and is the least-processed version of casein. It's the complete casein protein featuring all five caseins: alpha, beta, gamma, delta, and kappa. It's made by separating the casein protein from whey, fat, and lactose in milk.

Other casein supplements, such as calcium caseinate and hydrolyzed casein, are made through different chemical processes.

Micellar casein digests much more slowly, and it holds longer-acting nutritional benefits.

Is Micellar Casein Safe?

As mentioned before, casein in all its forms is generally safe for human consumption. However, if you're allergic to casein (i.e., milk proteins), you'll also be allergic to micellar casein.

The Verdict: When Should You Use Casein?

Casein protein has numerous health benefits, and it can help boost performance and protein synthesis for athletes.

But is there a need to include it as your preferred protein supplement? That largely depends on your goals.

In general, whey protein is the preferred dietary supplement for many athletes, as it's rapidly ingested and helps support muscle repair and building.

The true benefits of casein, and in particular micellar casein, lie in their slow-releasing activity.

If consumed at night, micellar casein can provide a slow release of amino acids during the time you're fasting (i.e., sleeping). In this way, casein helps provide amino acids over a longer period of time to help with muscle building, which is great for anyone who is dedicated to training, and it helps prevent the breakdown of protein, thus aiding recovery.


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