- 1. What is Casein Protein?
- 2. Benefits of Casein Protein
- 2.1. Casein Benefits Review
- 3. How is Casein Protein Made?
- 4. What are Casein Hydrolysate and Micellar Casein?
- 5. How should I take Casein Protein?
- 6. When is the best time to take my casein protein supplement?
- 7. Whey vs. Casein
- 8. Best Casein Protein Powders
- 9. Casein FAQ
- What casein protein powder is, and how it is different than other protein sources like whey protein.
- The different types of casein protein that are available.
- The major benefits of casein supplementation for those looking to build muscle and/or burn fat.
- The recommended amount of casein protein to take, and the optimal times to take it.
What is Casein Protein?
If you read our guide on whey protein you will know that whey protein is the term used to describe a group of milk proteins that are isolated from whey, which is the left over product of milk after it is coagulated during the cheese making process.
Casein is the other predominant form of protein found in milk and makes up roughly 80% of the protein found in cow’s milk. Much like whey, casein also contains a host of bioactive peptides that have additional properties beyond their muscle building capacity. Casein is the Yin to Whey’s Yang.
Casein protein is often misconstrued in the popular media and the nuances of it are not well discussed. This expert guide will wade through a lot of the marketing hype and give you the information you need to know about it.
We will break down what it is, how it is made, the different forms of it, and some of the most frequently asked questions regarding its use.
Is Casein Protein Safe?
Based on what we currently know, which is quite a lot, casein appears to be perfectly safe for human consumption.
There is this age-old myth that protein supplements hurt your kidneys. Well this just isn’t true. Not at all. In fact, every singly study to date has shown that high protein intake literally does nothing bad to your kidneys if you are a normal healthy individuals. PROTEIN DOES NOT HURT YOUR URINE MAKERS.
Now if you have establish kidney disease it is likely wise to keep it to moderate amounts but in otherwise healthy people, even intakes up to 4g/kg per day appears to be just fine!
Sadly, the myths and hyperbole surrounding protein supplementation, including casein don’t stop there. For a while it was thought that casein was linked to cancer but this turns out to be really, really, far from the truth. In fact, let’s dive into that topic.
Does Casein Cause Cancer? (The Chinese Study)
As a scientist one of my biggest pet peeves is when someone misinterprets (read over interprets) data and makes a big hot mess of a subject. The China Study did precisely that.
The summary of the China Study as told by the author goes like this, “animal protein caused cancer in mice and consuming more protein was associated with cancer in humans in China”. . . Well, unfortunately that just isn’t the truth.
So here is the real story of the China Study. . . .
Initially, studies done on rats that were poisoned and fed a 20% casein diet develop cancer-like lesions while those rats that consumed 5% casein did not. Let’s just ignore the fact that mice didn’t evolve to eat high amounts of casein or fish protein or anything else like that and give them the benefit of the doubt and discuss the actual research.
When you look at the actual data from the animal studies (we actually went in and read all of them, there are a lot of them) the cumulative research basically shows that either fish protein, casein protein, or plant protein has the ability to change tumor progression in mice exposed to tumor compounds.1-6
That is kind of like saying, “If you go into a nuclear reactor you probably are going to get tumors and eating a ton of protein might make it worse”. To me, the studies from the mice just don’t mean anything to us as humans not walking into toxic chemical plants or nuclear reactors on a daily basis.
Now clearly the whole poison/toxic thing is a huge piece and you can’t even come close to saying casein causes cancer in this study.
If I tried to publish a paper like that right now the reviewers would laugh at me. . . and then reject my paper.
Now it gets even worse, when you look at the actual data in the human studies the results are all over the map. Casein/animal protein intake was associated with a small increased risk of some types of cancer in SOME provinces in China.
However, it was also linked to much lower risks of some types of cancer in others provinces in China. Essentially, they found basically no good correlational data and they certainly found ZERO casual data.
I think it is safe to say that casein is clearly safe for human consumption.
Do I Have a Casein Allergy?
I honestly have no idea. You could, or you might not. Casein allergies are not uncommon as it is essentially an allergy to milk proteins. If you find that you have any symptoms of allergic reactions after consuming either milk or casein you should consult a doctor prior to taking casein protein or if they experience allergy symptoms after consuming it.
Some people can actually consume hydrolyzed casein with no side effects as it has been broken down into smaller peptides that don’t cause the same immunologic reaction as the full peptides do.
Casein Protein Benefits
Can Casein Protein be Used For Weight Loss?
Consuming dietary protein in the form of supplemental protein is a very well-established tool for weight loss protocol. One of the benefits of increasing protein intake comes from its ability to keep you satiated for longer periods of time than consuming carbohydrates or fat. For many people a high protein meal can sustain the feeling of fullness greater than a high carbohydrate or high fat meal.
Both whey and casein supplements have been researched as weight loss tools. When we look at the research from a weight loss perspective casein is likely to have a slight edge on whey protein, albeit it indirectly. One potential benefit of casein over whey is the “fullness” effect of casein.
As it is slower digesting it often results in a longer period of post-prandial (after eating) satiety. This may help reduce overall caloric intake and benefit weight loss to a greater degree than whey.
Casein Protein Benefits Review
- Casein is a great way to help hit your daily protein requirements.
- Casein offers a complete profile of amino acids.
- Casein can help with maintaining muscle mass during dieting cycles.
- Casein is an excellent protein source to promote satiety.
- Using casein in baked goods can increase the protein content and add texture.
How is Casein Protein Made?
Like we discussed in the Whey Protein Guide, whey is separated from the milk using straining methods. This results in a liquid whey product. The left over solid part (also known as the insoluble part) is the casein protein.
When manufacturing casein, whole milk is usually treated with a chemical, typically chymosin, which causes the milk to coagulate and makes the casein form a solid mass.
It is then sent through a series of microfilters that purifies it and concentrates the micellar segments of casein. Micelles are simply arrangements of molecules in which the water loving part of the molecule (hydrophilic) are directed toward the outside and the water hating part of the molecule (hydrophobic) are directed toward the inside. This gives it its unique digestive properties.
Foods High In Casein
While you can get casein from casein supplements you can also get a substantial amount from food sources. Casein is highest in dairy products like milk, cheese, cream, and yogurt. Casein is also found in some fish like tuna, although in much smaller quantities than dairy products
Casein Content in Milk
Milk is one of the highest sources of casein available as roughly 80% of milk proteins are casein. So if you drink an 8oz glass of milk that has roughly 12 grams of protein, you get about 9.6 grams of casein based proteins. That is quite a lot!
What are Casein Hydrolysate and Micellar Casein?
Micellar casein is the least adulterated form of supplemental casein. It is left in its “intact” molecular structure. This is important as it then is digested in a series of enzymatic and nonenzymatic processes in the body to encourage slow breakdown and absorption by the body.
Hydrolyzed casein is simply micellar casein that has been broken down into smaller peptides by “hydrolyzing” the bonds. This process occurs just like it does in whey where it can be broken down using enzymes or acids. If you decide to go with hydrolyzed casein for some of the reasons we mention below, definitely go with the hydrolyzed as the acid makes it incredibly bitter.
Typically, hydrolyzed casein will be substantially more expensive than micellar casein due to the processing and extra steps in manufacturing. There doesn’t appear to be any magical properties of hydrolyzed casein over hydrolyzed whey. The magic of casein lies in the micellar form so speaking honestly, if you want something hydrolyzed go with a hydrolyzed whey.
Assessing Protein Quality
Here is the deal. It is really difficult for the average person to conduct the necessary tests to find out exactly what the quality of their casein protein is. Honestly, most casein proteins from reputable companies have high quality protein content. We recommend buying your casein from our list of reputable brands.
However, just like any other food product, if it is handled and manufactured poorly there can be some dangers. That being said, the potential dangers are so miniscule that they are massively outweighed by the potential benefits for most people.
How Should I Take Casein Protein?
Chew it by the spoonful. Just kidding! There is no special way to take casein protein. It can be consumed on its own, in a smoothie, in a bowl of oatmeal, or mixed in with ice cream or pudding.
Casein should be considered a supplemental source of protein and not the primary source of protein in your diet as it is not typically as nutrient dense in vitamins and minerals as animal proteins.
When to Take Casein Protein?
Casein protein can be taken at any time of day and with any meal. It is often slower digesting and conveys longer lasting satiety than whey protein so it can be used for snacks or other times when you know you will have long stretches without a full meal (i.e. travelling) more effectively than whey protein.
There is also some rationale for taking it a few hours before training to ensure adequate amino acid delivery during training; however no studies really show it to be significantly better than whey protein, although casein may be a bit more effective if you take it a few hours prior to training than whey might be.
Casein Protein Before Bed?
One of the biggest marketing claims for casein protein is that it is the ultimate nighttime protein due to its slow digesting properties. The theory goes like this: consuming casein before bed ensures a slow, stead infusion of amino acids throughout the entire night.
When you look at the research one common theme emerges. If you are trying to get jacked and put on muscle, consuming protein before bed is probably going to help you get a little more recovery and muscle protein synthesis than not taking it. When you compare casein to whey it looks like there might be a slight advantage; however that advantage doesn’t appear to be gigantic in short term studies.
Our philosophy is, “you train your face off in the gym, might as well err on the side of gains in your nutrition”. So if you are trying to dial in supplementation as much as you can, taking casein at night might provide some extra benefit for you over whey protein.
It also is much better in things like mug cakes, protein cookies, and protein brownies and other dessert type concoction than whey due to its ability to act as a thickening agent.
Whey vs. Casein
Difference Between Whey and Casein?
People often make big claims about whey versus casein. There are probably over 1,000 articles on the internet about this issue but we really shouldn’t think of them as mutually exclusive. In fact, a smart supplementation regimen can include both. Let me cover some data about why this might be.
A study done in 23 individuals showed that both whey and casein had a similar effect on muscle anabolism after resistance exercise7.Another study showed that whey hydrolysate was more effective at eliciting muscle protein synthesis after exercise than casein8.
The findings of the above study were replicated in an older population where whey again outperformed casein in measures of muscle protein accretion.
Finally, in an isotope labeled infusion study, researchers were able to show that both whey and casein lead to similar increases in muscle protein synthesis9.
However, as we have discussed above potential benefit of casein over whey is the “fullness” effect of casein. As it is slower digesting it often results in a longer period of post-prandial satiety. This may help reduce overall caloric intake and benefit weight loss to a greater degree than whey (this is speculative on my part).
Additionally, it has been shown that night time casein is effective for recovery10.
Another, non-scientific aspect of casein is that when used in food production (i.e. baking) it can act as a thickener and give baked goods and smoothies a thicker texture.
So clearly each one has a role. If you need a quick acting protein go with whey. If you need one for bed time, or when you have large breaks between meals go with casein.
Should I Mix Whey and Casein?
This is a genius idea. . . and something I had not given much thought to before. Mixing whey and casein might be a great way to get some fast delivery of amino acids and also some slow delivery of amino acids.
One thing to note about mixing protein powders is their flavors are often different so be careful of the flavor combo you choose! (Pro tip: mix chocolate with a peanut butter one and you will get a killer combo).
Best Casein Protein Supplements
Total Fat: 1g
Total Carbohydrate: 2g
Total Protein: 24g
2. Optimum Nutrition
100% Casein Gold Standard
Total Fat: 1g
Total Carbohydrate: 3g
Total Protein: 24g
Total Fat: 0g
Total Carbohydrate: 4g
Total Protein: 25g
Total Fat: 1g
Total Carbohydrate: 2g
Total Protein: 28g
Total Fat: 1g
Total Carbohydrate: 4g
Total Protein: 25g
Does whey contain casein?
Whey should not contain casein as it is separated from the casein protein during the process. It is possible that some casein can be found if the processing of your whey protein was not done correctly; however, even in this scenario the amount of casein present would be incredibly small and not have any meaningful difference in terms of muscle growth or long term outcomes.
Does casein work?
This is a loaded question, but yes casein works and it works quite well for a lot of different goals. It can be used to effectively meet your daily protein requirements. It can be used as a slow release protein at night and has been shown to be effective for increasing overnight muscle protein synthesis. It has shown comparable results to whey for lean muscle gains in several studies.
Another really “successful” aspect of casein is its ability to act as a thickener in food. You can make the ever popular “protein fluff” with it and you can use it as a type of thickener in baked goods.
Is casein safe for teenagers?
Based on the current scientific evidence (and there is an obscene amount of studies using casein protein in humans), there is no evidence to suggest it is harmful for teens. In fact, it may actually be beneficial for teenagers as a lot of the components of casein will help their growing bodies!
Does casein help you fall asleep?
To our knowledge there isn’t any good research to support the idea that casein per se can help you fall asleep. There is some rationale that protein intake might help some people fall asleep if it contains a high proportion of tryptophan but that is also pretty much pure speculation.
One thing that can be said is that eating often increases parasympathetic activity and decreases sympathetic nervous system activity. This might aid in helping someone fall asleep but it is more the result of eating than it is the actual casein itself.
Is a casein protein supplement OK if I have an allergy to milk?
Allergies are primarily an immune response to proteins. As such, most people with milk allergies are allergic to specific proteins in the milk. Casein proteins can contain specific proteins that cause allergic reactions to milk so it is wise to consult a doctor prior to taking casein.
In general, people who have an allergic response to milk often have an allergic response to casein supplements. If this is the case you might do better with a plant based protein that contains a full spectrum of essential amino acids.
Is a casein protein supplement okay if I am lactose intolerant?
People have varying degrees of stomach and intestinal reactions to casein protein. Casein proteins are often lactose free or have a very small amount of lactose. This means it is unlikely that a lactose free casein product will result someone having gastric distress as a result of taking it.
However, if you try a casein-based product and find you are indeed sensitive to it a plant based product with a full range of essential amino acids is a viable alternative.
Can women take casein protein? Is there special casein protein for women?
There is no good evidence or theoretical rationale for why women can not or should not consider taking a casein protein. In general, women may weigh less than men which will result in a lower total daily protein intake but that does not indicate that casein supplementation is contraindicated for them.
Do rice, soy, or almond milks contain casein protein?
Casein is an animal milk based protein. Plant based protein milks do not contain any animal milk based products so they do not contain any casein protein.
How much protein should I aim for everyday?
Protein requirements or goals occur across a broad spectrum and are often dictated by your goal. There is no single recommendation that pertains to everyone but there are general guidelines that we can follow. Based on the most current data from research it appears that in order to optimize lean muscle protein intake should be set at a minimum of .6-.7 grams per pound per day.
This number can go up to 2 grams per day. A good range for the vast majority of people is to fall somewhere between 0.7 grams to 1.2 grams per pound per day.
Individuals who engage in more endurance type training (i.e. running, cycling, etc) can stick to the lower end of the range. Individuals who focus primarily on building muscle can stick to the higher end of the range (1-1.2 grams per pound per day).
I’m a vegetarian, can I use casein supplements?
Casein is derived from animal byproducts and does not contain any animal flesh so if you are a lacto-ovo vegeterian you can indeed consume casein protein. If you are a vegan and you choose to not consume any animal products than casein may not be right for you.
Can’t I just drink milk instead of buying a casein supplement?
As we mentioned above milk is a rich source of casein and you can indeed get a lot of casein protein by simply drinking milk. However, casein supplements may be more versatile and are more easily transported than milk.
Is casein useful for runners (or endurance athletes)?
Casein is 100% useful for runners as it can help them meet their daily protein needs and can be a great source of on-the-go protein. Combining it with whey may make for a great meal replacement option if you are a busy person who needs an on the go meal with high protein content.
- Inhibition of hepatocellular carcinoma development in hepatitis B virus transfected mice by low dietary casein.
- The sustained development of preneoplastic lesions depends on high protein intake.
- High protein intake promotes the growth of hepatic preneoplastic foci in Fischer #344 rats: evidence that early remodeled foci retain the potential for future growth.
- Dietary protein level and aflatoxin B1-induced preneoplastic hepatic lesions in the rat.
- Effect of dietary intake of fish oil and fish protein on the development of L-azaserine-induced preneoplastic lesions in the rat pancreas.
- Effect of high and low dietary protein on the dosing and postdosing periods of aflatoxin B1-induced hepatic preneoplastic lesion development in the rat.
- Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men
- Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men
- Whey and casein labeled with l-[1-13C]leucine and muscle protein synthesis: effect of resistance exercise and protein ingestion
- Physical Activity Performed in the Evening Increases the Overnight Muscle Protein Synthetic Response to Presleep Protein Ingestion in Older Men.