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Casein Protein: What is it? What are its Benefits & Usage?

Introduction to Casein Protein

Protein is a crucial nutrient for muscle growth, repair, and overall health. Among the various protein sources available, casein protein stands out for its unique properties and benefits. In this article, I will cover what casein protein is, its benefits, and how it can be incorporated into your diet.

What is protein?

Protein is one of the three macronutrients alongside fat and carbohydrates and contains 4 calories per gram. It is made up of amino acids, which are the building blocks of proteins. The body uses amino acids to build and repair muscles and bones, make hormones and enzymes, and utilises them as an energy source (1).

Amino acids: the building blocks of protein

An amino acid is a molecule that serves as the building block of proteins. There are 20 amino acids that the body needs to function correctly, with nine of them classified as essential amino acids (EAAs) because the body cannot produce them on its own and therefore must be obtained through the diet (2). Amino acids are crucial for various bodily functions, including muscle growth, tissue repair, and energy production.

Branched-Chain Amino Acids (BCAAs) are a subset of essential amino acids that play a significant role in muscle protein synthesis and growth (3). The three BCAAs are Valine, Leucine, and Isoleucine. These amino acids are particularly important for muscle recovery, reducing muscle soreness, preventing muscle damage during exercise, and promoting muscle growth. Leucine, in particular, has a significant anabolic effect and is crucial for stimulating muscle recovery through pathways like mTOR (mammalian target of rapamycin).To create new muscle protein, all the amino acids must be present in adequate amounts (especially the essential amino acids) so taking BCAA’s in the absence of other amino acids isn’t going to support muscle growth (4).

Dietary Protein Types

Protein is abundant in many foods and knowing which foods contain dietary protein will help you decide your food choices.

Some dietary protein types include:

Lean meats like beef, lamb, veal, pork and venison.
Poultry such as chicken, turkey and duck.
Fish and seafood like fish, prawns, crab, lobster, mussels, oysters, scallops, and clams
Eggs
Dairy products including milk, yoghurt (especially Greek yoghurt), and cheese (especially cottage cheese).
Protein powders such as whey, plant based protein and casein.
Nuts and seeds such as almonds, pine nuts, walnuts, macadamias, hazelnuts, cashews, pumpkin seeds, sesame seeds, and sunflower seeds.
Legumes and beans like all beans, lentils, chickpeas, split peas.
Tofu, seitan and tempeh.

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Complete proteins contain all nine essential amino acids in consistent amounts, while incomplete proteins lack one or more of these essential amino acids (14).

Complete Proteins:

1. Chicken

2. Beef

3. Fish

4. Dairy products

5. Quinoa

6. Soy

Incomplete Proteins:

1. Nuts

2. Seeds

3. Grains

4. Vegetables

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Casein Protein vs. Other Protein Types

Casein is a slow-digesting protein, releasing amino acids gradually over several hours. This provides a sustained supply of amino acids to the body whereas whey protein is a fast-digesting protein that is rapidly absorbed and metabolised within an hour. Plant proteins like pea or hemp tend to have slower absorption rates compared to whey but faster than casein.

Whey protein is best used around training sessions due to its absorbability with casein being a good option at other times of the day to bump overall intake. Plant based protein can be used if you are vegan or intolerant to dairy.

Amino Acid Profile

Whey protein is higher in branched-chain amino acids (BCAAs) like leucine, which are key for muscle protein synthesis.
Casein has a lower proportion of BCAAs compared to whey.
Many plant proteins lack or are low in certain essential amino acids, requiring combining different sources for a complete profile.

Muscle Protein Synthesis

Whey's rapid amino acid delivery makes it more effective at acutely stimulating muscle protein synthesis post-workout.
Casein's slow release is less effective for acute muscle protein synthesis but can help prevent muscle protein breakdown over longer periods like overnight.

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What is Casein Protein?

Casein is not a single protein, but rather a family of related phosphoproteins that make up around 80% of the proteins found in cow's milk. The remaining 20% is whey protein. The main components of casein are:

Alpha-caseins (αS1 and αS2)

αS1-casein is the most abundant, making up around 38% of total casein
αS2-casein makes up around 10% of total casein

Beta-casein (β-casein)

The second most abundant at around 36% of total casein

Kappa-casein (κ-casein)

Makes up around 13% of total casein
Plays a key role in casein micelle stability and structure

It is rich in calcium and phosphorus and provides a complete profile of essential amino acids, making it a high-quality protein source. Complete proteins contain all nine essential amino acids in consistent amounts, while incomplete proteins lack one or more of these essential amino acids (5).

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Benefits of Casein Protein

Casein is a slow-digesting protein, releasing amino acids gradually over several hours. This provides a sustained supply of amino acids to the body.

Casein is considered a slow-digesting protein due to several key factors:

Micellar structure: Casein proteins exist in milk as large micellar complexes bound together by calcium phosphate. This micellar structure slows down the digestion and absorption of casein compared to whey, which exists as individual protein molecules.
Coagulation in the stomach: When casein reaches the acidic environment of the stomach, it forms a gel or curd. This coagulation slows gastric emptying and delays the release of amino acids into the intestines for absorption.
Phosphorylation: Casein proteins are highly phosphorylated, which increases their ability to bind calcium and form insoluble complexes that are digested slowly.

Casein is Highly Satiating

Casein may be beneficial to those trying to lose weight. One of the biggest factors in weight loss success is managing hunger. Casein can help with -

Increasing satiety hormones: Studies show that casein consumption can increase levels of satiety hormones like cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), which suppress appetite (12). It may also increase levels of the hunger-regulating hormone ghrelin in overweight individuals.
Reducing calorie intake: Due to its satiating effects, research indicates that casein can help reduce overall calorie intake compared to other protein sources or placebo. One study found casein decreased energy intake to a greater extent than whey protein.
Preserving lean body mass: Casein's slow release of amino acids is thought to help prevent muscle protein breakdown, which can aid in preserving lean body mass during dieting phases. This can support a higher metabolic rate compared to losing muscle mass. Remember you want to lose body fat, not muscle.

While there is limited data regarding the effect of nighttime protein consumption on metabolic parameters, a 2021 study (15) found no difference in lipolysis (breakdown of fats by the body) whether casein was consumed during the day or pre-sleep, highlighting that pre-sleep protein is a viable option for increasing protein consumption in resistance-trained women because it does not blunt overnight lipolysis, and will therefore likely not lead to increases in subcutaneous abdominal fat.

Casein can help with muscle growth

One of the main reasons casein supports muscle growth and recovery is down to the complete amino acid profile and high overall protein content. It is commonly used pre sleep due to it being slow digesting. Numerous studies have shown that consuming casein in the 1-2 hours before sleep can have a positive effect on muscle growth and recovery from exercise (6,7,8,9,13).

In addition to this, a recent study explored the benefit of protein prior to sleep on mitochondrial protein synthesis (10). They found that protein ingestion before sleep increases both mitochondrial and myofibrillar protein synthesis rates during overnight recovery from exercise. The overnight muscle protein synthetic response to whey and casein protein does not differ.

However, casein does not always need to be used before sleep. A recent study used 100g of protein post-workout (of which it was 80% casein) and saw some excellent results (11). They found a dose-response relationship - the 100g protein group had a significantly higher and more sustained increase in muscle protein synthesis rates than the 25g group.

Casein can help with bone health

Casein protein is rich in calcium and phosphorus, which are essential minerals for bone health. Regular consumption of casein protein can help improve bone density and reduce the risk of osteoporosis. Research has shown that casein-derived peptides can enhance calcium absorption and support bone health (14).

Coupling casein protein intake with a structured resistance training program can further boost your bone mineral density.

Casein Protein Dosage and Timing

The notion that you require 25g of protein per serving and anything over this is oxidised or wasted has been debunked to an extent from the aforementioned study (11). The hierarchy of importance when it comes to protein is

Total daily protein
Protein distribution
Timing and type

Focusing on the timing of your protein is irrelevant if you do not eat enough overall protein. But if you are eating enough then distributing more evenly and especially around training may offer small benefits.

Using a casein protein such as MARCHON micellar casein can help you reach the recommended daily targets needed for your goal. The table below shows the targets to follow based on your goal and activity.

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Breaking this down it can be done in any split but realistic you are going to want to split this into 3-5 feeds across the day. Although overall intake is the most important it is challenging to eat enough in 1-2 servings. Plus eating protein across the day can help reduce hunger levels as well as support muscle growth.

How to Incorporate Casein Protein into Your Diet

One of the most convenient ways to consume casein protein is through casein protein powder such as our micellar casein. It can be mixed with water or milk to make a shake or you can use less liquid and make it into a mousse, which is ideal for a pre-bedtime snack.

Another way is to consume dairy products. Natural sources of casein protein include foods such as milk, cheese, and yoghurt. These can be incorporated into meals and snacks to boost your casein intake.

And lastly, many protein bars and snacks contain casein protein. These are great options for on-the-go nutrition and can help keep you full between meals.

Conclusion

Overall, casein is considered a high-quality, slowly-digested protein source with various applications for fitness, muscle recovery, bone health and enhancing your overall daily protein intake. It can be used at any time of the day but has particular benefits during periods where protein intake will be low such as sleep.

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Frequently Asked Questions (FAQs)

Is casein protein safe to consume daily?

Yes, casein protein is generally considered safe for daily consumption when taken in appropriate amounts. As a natural dairy protein, casein is a high-quality, complete protein source that provides all the essential amino acids.

Can I use casein protein for weight loss?

Casein protein can potentially help during fat loss diets due to its ability to promote feelings of fullness and satiety. The slow digestion and absorption of casein can help reduce calorie intake and prevent overeating. Additionally, casein's muscle-preserving effects may help maintain a higher metabolic rate during calorie-restricted diets.

What's the difference between casein and whey protein?

The main difference between casein and whey protein lies in their digestion and absorption rates. Casein is a slow-digesting protein that releases amino acids gradually over several hours, providing a sustained supply of amino acids. In contrast, whey protein is a fast-digesting protein that is rapidly absorbed and metabolised within an hour. Whey is often considered more effective for stimulating muscle protein synthesis immediately after a workout, while casein is better for preventing muscle protein breakdown over longer periods, such as overnight. However there is context to apply here as what you eat it with and the time of the day you take can also affect digestion rates (post training vs away from training)

Can I take casein protein before bedtime?

Yes, casein protein is often recommended as a bedtime or pre-sleep supplement due to its slow digestion rate. Consuming casein before bed can provide a steady supply of amino acids to the muscles throughout the night, supporting muscle recovery and growth while you sleep. Mixing MARCHON micellar casein with around 150ml of water can make a thick mousse to consume around 1 hour pre sleep.

Is casein suitable for vegetarians?

Yes casein protein is suitable for vegetarians but not vegans. Casein is a milk-derived protein that comes from dairy products like cow's milk. Since vegans avoid all animal-derived food products including dairy, casein would not be an appropriate protein source for them. Plant-based protein powders like the MARCHON plant protein would be better suited.

Are there any potential side effects of casein?

While generally considered safe for most people, there are some potential side effects to be aware of with casein protein:

1. Allergic reactions in those with milk/dairy allergies, as casein is the primary milk protein.

2. Digestive issues like bloating, gas or constipation in some individuals, especially with larger doses.

However, for most healthy adults without allergies, casein is well-tolerated with no major side effects when consumed in appropriate amounts.

Can casein protein be used as a meal replacement?

While casein protein powder can be used to increase overall protein intake, it should not be relied upon as a complete meal replacement. Casein is just a single source of protein and lacks other essential nutrients like healthy fats, fibre, vitamins and minerals that a balanced meal would provide.

Casein could potentially be used as part of a meal replacement shake or smoothie when combined with other nutrient-dense ingredients like fruits, vegetables, nut butters, etc. But relying solely on casein powder without other whole foods would lead to nutritional deficiencies over time.

Does casein protein help in preventing muscle breakdown?

Yes, one of the key benefits of casein protein is its ability to prevent muscle protein breakdown, especially during periods of calorie deficit or when going for extended periods without food.

The slow digestion and absorption rate of casein provides a sustained release of amino acids to the muscles over several hours. This helps reduce muscle catabolism (breakdown) by maintaining a positive protein balance.

Consuming casein before bed is particularly effective for preventing overnight muscle breakdown while fasting during sleep. This makes casein useful for bodybuilders, athletes and anyone engaged in intense training.

Can I mix casein with other protein sources?

Yes, you can mix casein with other protein sources like whey protein.

Is casein protein suitable for individuals with lactose intolerance?

Casein protein itself does not contain lactose, the sugar found in milk that causes issues for those with lactose intolerance. However, there are some important considerations:

Pure casein or casein protein supplements that are lactose-free can generally be consumed safely by most lactose intolerant individuals.
However, many casein protein powders and supplements may contain trace amounts of lactose from the milk they were derived from. These trace amounts could potentially cause symptoms for those with severe lactose intolerance.
Individuals with a milk protein allergy (versus lactose intolerance) would need to avoid casein and all milk proteins completely, as their body has an immune reaction to the proteins.

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So in summary, while pure, isolated casein protein is technically lactose-free, many casein supplements contain small amounts of lactose. Highly sensitive individuals may need to avoid casein powders derived from milk altogether and opt for non-dairy, plant-based protein sources instead.

Can I use casein protein for bulking?

Yes, casein protein can be used for bulking and building lean muscle mass. Research indicates that casein protein stimulates muscle protein synthesis and supports muscle growth and repair when combined with resistance training.

Can casein protein be used for maintaining muscle mass during a calorie deficit?

Yes, casein protein can help preserve lean muscle mass during periods of caloric restriction or deficit. Studies demonstrate that casein protein supports muscle protein synthesis and prevents muscle breakdown when combined with resistance training.

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