Protein is an essential nutrient that is part of every cell in your body. It also helps produce important chemicals including hormones. Casein is a type of protein found in milk and milk products.
In people with milk allergies, casein may be the culprit. The protein sometimes shows up in unsuspected products, so awareness is essential if your doctor has advised you to avoid it. If you can tolerate casein, it's an effective protein for building muscle, and those desiring an edge in their training seek out food products with a heavy dose of it.
Casein Protein Foods
Casein and whey are the two primary protein types in milk. All cow's milk contains casein, according to HealthLine. Cream, half and half, yogurt and sour cream are other high-protein dairy sources of casein. Ice cream, butter, cheese and pudding also contain it. Foods made with these products — such as cream-based soups, sherbet, pudding and custard — are also casein-rich. Casein protein is also available in powder form. Dairy milk alternatives — such as coconut, almond and soy milks — do not contain casein.
Slow Release Protein
According to a 2017 study in the International Journal of Exercise Science, casein protein is considered to be a slow release protein, as it digests more gradually than other protein sources such as whey. Amino acids — the building blocks of protein — give structure to tissues in your body. Casein protein releases amino acids into the blood for approximately 7 hours, while other proteins such as whey are digested in approximately 3 hours.
Fast acting proteins, including whey, release amino acids into your bloodstream quickly, allowing your body to use these nutrients right away. For this reason, fast acting protein sources are better choices than casein when consumed right before or immediately after a workout.
According to HealthLine, slow digesting casein protein helps build and maintain muscle mass. If you are low on energy, have been dieting or exercising intensely, your body can break down muscle tissue to boost amino acid levels. Consuming casein provides an alternate source for amino acids, which in turn helps to preserve this muscle mass.
Less Obvious Sources
Margarine, tuna, dairy-free cheese, non-dairy coffee creamer, semisweet chocolate, cereal bars, cheese-flavored chips and snack crackers, processed meats and ghee may have traces of casein protein. Baked goods are another food of which to be wary because many contain milk or buttermilk. Casein can also be found in baby formula.
These foods are of concern for those allergic to casein. If you want to use casein as a supplement to encourage muscle growth after workouts, these types of products that contain small amounts of casein should not be your focus.
Check the Ingredients
Reading food labels helps you identify the presence of casein. The ingredients "lactic acid" and "artificial flavorings" mean a food could have casein in it. Avoid these products, or call the manufacturer to make sure they're safe if you have an allergy. Foods that list "caseinate" on the label definitely contain casein. Beware that dairy-free doesn't mean casein-free.