Casein protein Everything you need to know about the 'slow' protein

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Casein protein is one of two milk proteins – the other is whey protein – and makes up about 80 percent of all milk protein. Casein is a slow-digesting protein, so it’s often seen as the lesser of the two milk proteins. That is not necessarily true, because casein has unique properties compared to the ‘fast’ whey.

Key points:

1.   Casein is a milk protein that is digested slowly, so that its amino acids are absorbed more gradually than those from whey protein.

2.   For optimal muscle growth, you should eat about 1.6 grams of protein per kilogram of body weight every day (the ‘protein quota’). Casein is a high-quality and healthy protein that contains all amino acids important for muscle growth in abundance, making it a suitable protein to contribute to that protein quota.

3.  For muscle growth, the total protein intake in one day is decisive. However, to optimally stimulate muscle protein synthesis, scientists recommend eating 20-40 grams protein per meal. And to spread those meals evenly throughout the day, so with three or four hours in between.

4.   Because casein is absorbed slowly, it seems ideal to take just before extended periods without food, such as at night. To do this, take a portion of 40 grams immediately before going to sleep. Nevertheless, it is still unclear whether you are able to increase muscle protein synthesis during the entire night’s sleep with such a ‘shot’.

5.   Due to the slower absorption, casein seems less suitable for use immediately after training. Then you may benefit more from a protein that stimulates muscle protein synthesis faster and therefore more powerfully, namely whey protein.

6.   Casein is in almost all dairy products. The largest amount of casein protein is found in cottage cheese. This food is therefore suitable to consume, for example, before going to sleep. However, casein powder provides more pure protein and is usually a bit cheaper.

CONTENTS


ORIGIN

Casein protein comes from curds. This is the solid mass that is created during cheese making, when rennet is added to (cow’s) milk and the casein proteins clump together (‘coagulate’). The liquid substance that remains is the whey, from which whey protein (whey) comes.

Curd is basically a precursor to cheese (while whey is in fact a by-product), but casein can also be extracted from it.

The origin of casein explains why a protein shake prepared with casein protein powder is thicker than a shake prepared with whey protein powder.

In summary:
Casein is an animal protein found in milk.

COMPOSITION

As an animal protein source, casein protein contains all the amino acids essential for the human body, in sufficient quantities.

LEUCINE CONTENT

Casein contains all amino acids that also occur in whey, but in a different composition. In total, casein contains fewer essential amino acids and fewer BCAAs than whey. Whey also contains more leucine (~11%), the most important amino acid for muscle building, although it is also present in a relatively high amount in casein (~8%).

Seen in this way, whey seems more suitable for muscle growth than casein, but remember that there is a so-called leucine ceiling: to optimize muscle protein synthesis, ~2.5 grams of leucine is needed and sufficient. Because it is best to take ‘shots’ of 20-40 grams of protein for optimal muscle growth, it makes no difference whether you use whey (~3 g leucine) or casein (~2.5 g leucine): in both cases you will achieve the leucine ceiling.

RECORDING SPEED

The big difference between casein and whey lies not so much in the ‘free’ amino acids, but in the way in which they are linked together. The amino acid chains (peptides) in casein are longer than in whey. As a result, they are digested more slowly in the stomach and absorbed more slowly by the intestines. Some even end up partially intact in the intestines: the so-called ‘bioactive peptides’. This ensures that the amino acids end up little by little in the blood and in the muscles.

French studies have shown that casein increases the amount of leucine in the blood for up to 7 hours after ingestion, while whey hardly increases after 3-4 hours. Whey does cause a higher increase in the amount of leucine half an hour to 3 hours after ingestion. Casein still rises during the first half hour, but then remains stable xii ] xiii ] .

HEALTH

Casein is good for your health. It contains several bioactive peptides that have been shown to benefit your immune and digestive system i ] [ ii ] . Some are also said to be good for your heart by lowering blood pressure and reducing blood clot formation iii ] [ iv ] .

In summary:
Casein is easily broken down into essential amino acids for the synthesis of other proteins, such as muscle proteins. Casein protein is digested slowly, so the amino acids from it are absorbed more gradually than those from whey protein. For example, after taking casein, the level of leuceine in the blood remains elevated for up to seven hours. With whey, there is an increase up to four hours after ingestion.

VARIANTS

The best known is micellar casein (micellar English) casein, a slowly digestible protein that usually is used for supplements. However, there are ultra-filtered casein proteins that digest even more slowly than micellar casein, which is produced via microfiltration.

On the other hand, there is also hydrolyzed casein, or casein hydrolyzate, whose protein structure has been manipulated in such a way that it is digested quickly, just like whey hydrolyzate.

In summary:
Micellar casein is the standard form of casein, which is usually also used for supplements.

CASEIN FOR MUSCLE GROWTH

For optimal muscle growth, you should consume about 1.6 grams of protein per kilogram of body weight daily. If you find it difficult to get all those proteins from your regular diet, protein powders are an effective and relatively inexpensive tool. Casein is a high-quality, complete and healthy protein, which makes it an excellent option for bodybuilders. Just like whey protein.

An ongoing point of discussion is whether whey is better for muscle growth than casein (or vice versa). It probably doesn’t matter that much, although the slow absorption rate of casein seems to provide a specific benefit, namely to provide your muscles with amino acids during nighttime sleep. But why is that actually necessary?

PROTEIN BEFORE GOING TO SLEEP

We already saw: to optimize muscle protein synthesis, it is best to take your proteins in portions (meals) of about 20-40 grams. Also make sure that those meals are more or less evenly spread over the day. In total you should arrive at about 1.6 grams per kilogram of body weight per day.

Although its precise effect requires more research, it is wise to take one of those servings of protein immediately before bedtime. This way you ensure that muscle protein synthesis can also remain elevated during your sleep.

It is unclear whether and to what extent it is possible to provide your muscles with protein throughout the night with one pre-nightly protein intake. This possibility seems more realistic if you take a somewhat larger ‘shot’ of proteins, of at least 40 grams, and if you use the slowly absorbing casein protein, says researcher Jorn Trommelen of Maastricht University, based on several studies.

In advanced bodybuilders, the so-called anabolic window probably closes quite quickly and the peak of muscle protein synthesis occurs within the first ten hours after training. Pre-night protein intake therefore seems more important to them than to novice and average bodybuilders, especially when training is done in the evening.

AND WHAT ABOUT WHEY PROTEIN?

Whey protein, in turn, has the advantage of being absorbed quickly, releasing a large amount of leucine into the blood within a few hours. As a result, whey is the most powerful and fastest protein to stimulate muscle protein synthesis, especially when the body, from an anabolic point of view, is perhaps most sensitive to protein absorption, namely in the hours immediately after training.

After training, muscle protein synthesis (MPS) often remains elevated for at least 48 hours. The peak in MPS seems to be around two and a half to three hours post-workout. (Source: McMaster University, 2014/Jeff Nippard)

The amino acids from casein are released in smaller amounts, which makes this protein less suitable for post-workout consumption.

ADVICE AND EXAMPLE

In any case, it is essential for muscle growth to get enough protein (~1.6 g/kg) throughout the day. Taking protein before sleep contributes to this, so you don’t do that for nothing. However, it makes no sense for muscle growth to eat more protein than necessary. It is much better to spend the rest of your calorie intake mainly on carbohydrates, the primary source of energy for strength training. If you really want to take protein before going to sleep, keep that in mind in your protein intake during the day.

Proteins are best taken in portions of 20-40 grams at a time, with 3-4 hours in between (with the exception of the night’s sleep). So a possible ‘schedule’ of intake for someone weighing 75 kg is:

  • breakfast: 30 grams of protein
  • lunch: 20 grams of protein
  • dinner: 30 grams of protein
  • after training: 30 grams of protein (whey)
  • before bedtime: 40 grams of protein (casein)
In summary:
Casein seems extremely suitable to take immediately before going to sleep. It may be better than whey protein to increase muscle protein synthesis for a long time, perhaps during the entire night’s sleep. Take a slightly larger portion than normal: around 40 grams.

WHICH FOODS CONTAIN CASEIN?

Casein is found in almost all dairy products, such as cottage cheese, cheese, yogurt and countless foods to which milk has been added, including many bakery products.

If you take a large amount of casein (20-40 grams) before bed, you probably want as little ‘by-product’ as possible. Cottage cheese seems to be the best option of the ‘regular’ foods: 100 grams of low-fat cottage cheese (~ 55 kcal) provides you with about 10 grams of casein protein, compared to 3.5 grams of carbohydrates and 0.5 grams of fat.

Casein, like whey, is also available in powder form. Casein powder normally provides you with the most favorable macronutrient ratio. For example, one scoop (25 g) of Micellar Casein Perfection from Body & Fit (93 kcal) contains 20.6 grams of casein protein, 1.3 grams of carbohydrates and 0.5 grams of fat. For a jar of 750 grams you pay € 12.90, which is probably cheaper than when you get jars of cottage cheese from the supermarket.

In summary:
Casein is found in almost all dairy products. The largest amount of casein protein is found in cottage cheese. This food is therefore suitable to consume, for example, before going to sleep. However, casein powder provides more pure protein and is usually cheaper too.

IN SUMMARY

1.    Casein is a milk protein that is digested slowly, so that its amino acids are absorbed more gradually than those from whey protein.

2.    For optimal muscle growth, you should eat about 1.6 grams of protein per kilogram of body weight every day (the ‘protein quota’). Casein is a high-quality and healthy protein that contains all amino acids important for muscle growth in abundance, making it a suitable protein to contribute to that protein quota.

3.  For muscle growth, the total protein intake in one day is decisive. However, to optimally stimulate muscle protein synthesis, scientists recommend eating 20-40 grams protein per meal. And to spread those meals evenly throughout the day, so with three or four hours in between.

4.    Because casein is absorbed slowly, it seems ideal to take just before extended periods without food, such as at night. To do this, take a 40-gram serving immediately before going to bed. Nevertheless, it is still unclear whether you are able to increase muscle protein synthesis during the entire night’s sleep with such a ‘shot’.

5.    Due to the slower absorption, casein seems less suitable for use immediately after training. Then you may benefit more from a protein that stimulates muscle protein synthesis faster and therefore more powerfully, namely whey protein.

6.    Casein is in almost all dairy products. The largest amount of casein protein is found in cottage cheese. This food is therefore suitable to consume, for example, before going to sleep. However, casein powder provides more pure protein and is usually a bit cheaper.

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