To understand why cheese is a complete protein, it's essential to first know what defines a complete protein. Proteins are made up of building blocks called amino acids. The human body needs 20 different amino acids to function properly, but it can only produce 11 of them. The remaining nine—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—are called essential amino acids because they must be obtained through food. A protein source that contains all nine of these essential amino acids is called a 'complete protein'.
The Proteins in Cheese
Cheese is a dairy product, and as such, it derives its protein from milk. The two primary proteins in milk are casein and whey.
Casein Protein
Casein makes up about 80% of the total protein in milk. During the cheesemaking process, casein coagulates to form solid curds, which are then pressed to form the cheese. Casein is a slow-digesting protein, meaning it provides a sustained release of amino acids into the body, which can be beneficial for satiety and muscle maintenance over longer periods. Casein contains all nine essential amino acids, making it a complete protein.
Whey Protein
Whey accounts for the remaining 20% of the protein in milk and remains in the liquid portion, or whey, during cheesemaking. While some whey protein may be lost during the process, some still remains in the final cheese product. Whey is a fast-digesting protein, prized for its ability to deliver amino acids to the muscles quickly. Like casein, whey is also a complete protein source. The presence of both casein and whey ensures that cheese offers a comprehensive amino acid profile.
Protein Content Varies by Cheese Type
The amount of protein in cheese is influenced by factors such as moisture content and age. Harder, aged cheeses generally have a higher concentration of protein per ounce because they have less water. Softer cheeses, with more moisture, have a lower protein density but are still complete protein sources.
Comparison of Protein Content in Different Cheeses
To illustrate the variability, here is a comparison of protein content (per 100g) for several common cheeses, based on data from various sources:
| Cheese Type | Protein (grams per 100g) |
|---|---|
| Parmesan | ~35.8g |
| Pecorino Romano | ~32.1g |
| Swiss (Emmental) | ~28.4g |
| Cheddar | ~25.0g |
| Mozzarella (whole milk) | ~24.0g |
| Feta | ~14.2g |
| Cottage Cheese (low fat) | ~11.0g |
| Cream Cheese | ~8.2g |
Nutritional Benefits Beyond Complete Protein
Beyond its complete amino acid profile, cheese offers other important nutritional benefits:
- Calcium for bone health: Cheese is an excellent source of calcium, a mineral vital for strong bones and teeth. Harder cheeses often contain more calcium.
- Vitamins and minerals: Cheese also provides other essential nutrients, including phosphorus, potassium, and vitamins A and B12.
- Healthy fats: While fat content varies by type, the fats in cheese contribute to its flavor and can help with satiety.
- Probiotics: Some aged, unpasteurized cheeses, like Swiss and Gouda, contain beneficial probiotics that can support gut health.
Conclusion: A Nutritious and Versatile Source
Yes, the protein in cheese is a complete protein, containing all nine essential amino acids needed by the human body. This is thanks to its dairy origin, which provides a high-quality protein blend of casein and whey. The specific protein content varies depending on the type and age of the cheese, with harder, aged varieties being more protein-dense. For most individuals, including cheese in a balanced diet is a delicious and effective way to help meet daily protein needs while also providing other valuable nutrients like calcium and probiotics. When consumed in moderation, cheese can be a powerful and satisfying component of a healthy eating plan.
For more information on protein quality and dietary needs, you can visit the Harvard School of Public Health's nutrition resource page on protein.
