Is Cheese First Class Protein? An In-Depth Look

October 28, 2025 •

3 min read

According to the American Dairy Association, dairy foods like milk and cheese are naturally high-quality, complete protein sources. So, yes, cheese is considered a first class protein because it contains all nine essential amino acids necessary for human health.

Quick Summary

This article explores why cheese is classified as a first class protein, detailing its complete amino acid profile derived from casein and whey. It covers the nutritional differences between hard and soft cheeses and compares its protein quality to other sources, providing comprehensive facts for informed dietary choices.

Key Points

Complete Protein: Yes, cheese is a first class protein because it contains all nine essential amino acids.
Casein and Whey: The primary proteins in cheese are casein and whey, both of which are complete proteins.
Varying Protein Content: The amount of protein per ounce varies by type, with harder, aged cheeses generally having more concentrated protein than softer varieties due to lower water content.
High Bioavailability: The protein in cheese is highly digestible and bioavailable, meaning the body can absorb and use its amino acids efficiently.
Nutritional Balance: While a great protein source, cheese should be consumed in moderation as part of a balanced diet due to its potential for high saturated fat and sodium content.
Beyond Protein: Cheese also offers other crucial nutrients like calcium, phosphorus, and Vitamin B12.

Understanding First Class Protein

To understand why cheese qualifies as a 'first class protein,' it's important to know the terminology. A first class, or complete, protein is any food source that contains all nine essential amino acids in sufficient quantities. These are amino acids that the human body cannot produce on its own, making dietary intake essential for muscle repair, tissue growth, and overall bodily function. Unlike many plant-based proteins, which are often classified as 'second class' due to missing or insufficient levels of certain essential amino acids, animal-based proteins from sources like meat, eggs, and dairy are typically complete.

The Protein Profile of Cheese

Cheese is a dairy product, and its proteins are inherited directly from milk. Milk contains two primary proteins: casein (approximately 80%) and whey (approximately 20%). Both casein and whey are complete proteins, meaning they contain a full spectrum of essential amino acids. During the cheesemaking process, casein coagulates to form the solid curds, while most of the whey is drained off as a liquid. Some whey protein remains in the final product, especially in softer cheeses.

Protein Content and Quality in Different Cheeses

The protein content in cheese varies significantly depending on the type and manufacturing process. Hard, aged cheeses typically have a higher concentration of protein because they have less water content. Softer cheeses, with their higher moisture, contain less protein per ounce.

Hard vs. Soft Cheese Protein Content

Let's compare a few common varieties:

Parmesan: A hard, aged cheese, Parmesan is one of the most protein-dense options, with about 8-10 grams per ounce.
Cheddar: Another hard cheese, Cheddar has a high protein content, averaging around 6-7 grams per ounce.
Swiss: Swiss cheese offers a solid protein serving, with roughly 7-8 grams per ounce.
Brie: A soft cheese, Brie contains less protein per ounce, typically around 6 grams.
Cottage Cheese: This soft, curd cheese is a protein powerhouse, offering about 14 grams per half-cup serving.

Protein Quality and Bioavailability

While the first class/second class protein classification is a useful starting point, more advanced metrics like the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and the Digestible Indispensable Amino Acid Score (DIAAS) provide a more accurate measure of protein quality. These scores account for both a protein's amino acid profile and its digestibility. Casein and whey, the proteins in cheese, score very highly on these metrics, confirming their status as high-quality, readily usable protein sources for the body. Research has even shown that whey-based cheese can provide higher levels of bioavailable amino acids compared to casein-based cheese.

Comparison Table: Cheese vs. Other Protein Sources


Protein Source	Type of Protein	Amino Acid Profile	Digestibility	Protein Per Serving (approx.)	Other Nutritional Notes
Hard Cheese (e.g., Parmesan)	Casein, Whey	Complete	High	8-10g per ounce	Also rich in calcium, phosphorus, and fat
Cottage Cheese	Casein	Complete	High	~14g per half cup	Lower in fat than hard cheeses; rich in calcium
Chicken Breast	Animal-based	Complete	High	~22.5g per 100g	Lean protein source; generally lower in fat
Tofu (Soy)	Plant-based	Complete	High	~17g per 100g	One of the few plant-based complete proteins
Lentils	Plant-based	Incomplete	Moderate	~5g per 100g	Lacks essential amino acid methionine; high in fiber

Nutritional Considerations Beyond Protein

While the high protein quality of cheese is a significant benefit, it's important to consider its other nutritional components. Cheeses can be high in saturated fat and sodium, particularly the harder varieties. For example, Cheddar is higher in sodium than Swiss. Many cheeses are also calorie-dense. Therefore, moderation and balance are key. Paired with other foods, cheese can contribute to a well-rounded and nutritious meal plan. Cheese is also an excellent source of other vital nutrients, including calcium, phosphorus, and vitamin B12.

Conclusion

In summary, is cheese first class protein? The answer is unequivocally yes. As a complete protein source derived from milk, cheese contains all the essential amino acids your body needs. Its high protein quality, bolstered by the presence of casein and whey proteins, makes it an excellent dietary component for muscle growth and repair. While hard and soft cheeses vary in their nutritional makeup—particularly in terms of protein density, fat, and sodium—all types offer high-quality protein. When consumed as part of a balanced diet that also considers its fat and sodium content, cheese can be a delicious and beneficial source of high-quality protein for nearly everyone.

Frequently Asked Questions

Yes, cheese is a complete protein source because, as a dairy product, it contains all nine essential amino acids required by the human body for proper function.

Hard cheeses, being more concentrated due to less water content, typically contain a higher percentage of protein per ounce compared to softer cheeses. However, some soft cheeses like cottage cheese are exceptionally high in protein per serving.

The protein quality of cheese is very high, confirmed by metrics like the Protein Digestibility Corrected Amino Acid Score (PDCAAS). The primary proteins in cheese, casein and whey, are both highly digestible and contain an excellent amino acid profile.

For individuals not following a plant-based diet, cheese protein is generally considered superior in terms of being a single, complete source. Many plant proteins are 'incomplete,' lacking one or more essential amino acids, though they can be combined to form a complete protein.

Yes, the protein content varies significantly. For example, hard cheeses like Parmesan can have over 30 grams of protein per 100g, while softer types like feta contain less per ounce, but are still a valuable source.

Yes, as a high-quality, complete protein source, cheese can effectively support muscle growth and repair. The casein protein in cheese is known for its slow-release properties, providing a sustained source of amino acids.

The classification 'first class protein' is somewhat outdated but remains a useful, general concept for describing proteins that contain all essential amino acids. Modern nutrition science uses more precise metrics like PDCAAS and DIAAS to assess protein quality.