Casein is a milk protein used as a dietary supplement.
Casein is a protein found in milk and dairy products. It accounts for roughly 80% of the protein in milk, cheese, and yogurt. (The other 20% is whey.)
Casein is also sold as a protein powder dietary supplement. It is commonly used by bodybuilders to promote exercise recovery and increase muscle size. Casein is also found in dairy-based baby formulas.
Uses of casein
Casein is a complete protein. This means it contains all of the essential amino acids required by the human body. In its purest form, casein is a white-colored solid with no taste. All mammals produce casein as a component in milk for their offspring.
Human breast milk consists of 40% casein and 60% whey, while cow's milk protein is 80% casein and 20% whey. Since casein binds to calcium and phosphorus, milk is a good source of these vital minerals.
Exercise recovery and muscle building
As a protein supplement, casein supplies muscles with the full range of amino acids required for exercise recovery and strength building. Proper sleep and adequate protein intake are critical for muscle recovery. Casein products work by providing an extra boost of protein to support muscle tissue.
Food industry
Casein is a primary component in cheese-making. It is also used to create infant formulas as a substitute for breast milk.
What are the side effects of casein?
For most people, casein supplements are probably safe. Most healthy adults do not experience side effects when taking casein at appropriate doses.
Precautions
Casein may not be suitable for everyone. It is always a good idea to discuss supplement use with your doctor before adding a new supplement like casein to your routine.
Allergies
If you have an allergy to milk, ask your healthcare provider whether you should have testing to detect the specific proteins responsible for your allergy. It's possible to be allergic to other proteins in milk, like whey, but not casein.
Allergic reactions to milk should not be confused with lactose intolerance. Many people are intolerant to lactose (milk's natural sugar) but will tolerate the casein in yogurt or cheese just fine.
Sources of casein and what to look for
Casein is available as a supplement, but it is also present in dairy products. Healthcare providers typically recommend whole foods over supplements since whole foods are more nutrient-rich.
Food sources of casein
A cup of whole milk has about 300 mg of calcium, much of which is found in casein. It also contains about 8 grams of protein. You can also get casein from cottage cheese and yogurt. A cup of 2% fat cottage cheese contains about 225 mg of calcium and 24 grams of protein. A cup of whole milk Greek yogurt contains about 235 mg of calcium and 19 grams of protein.
Casein supplements
As a supplement, casein usually comes as a powder. It can be mixed with water or milk to make a protein shake. It can be purchased in various flavors such as chocolate and vanilla for palatability.
Summary
Casein is a protein found in dairy products. It is often used by bodybuilders to support exercise recovery. Because it contains calcium, it may also support bone health.
Casein should not be used by people with milk allergies. It is always a good idea to talk to your healthcare provider about adding casein or any other supplement to your routine.