What are high biological values and why do they matter?

December 28, 2025 •

4 min read

Did you know that not all proteins are created equal? Proteins are fundamental to life, but their quality varies dramatically based on their biological value (BV). High biological values indicate how efficiently your body can absorb and utilize the protein you consume, directly impacting your body's growth and repair processes.

Quick Summary

This article defines biological value (BV), explaining how high BV proteins provide a complete profile of essential amino acids for optimal bodily function. It explores measurement methods, lists high-BV food sources, and contrasts BV with other protein scoring systems like PDCAAS to help you make informed dietary choices.

Key Points

High Biological Values (BV) measure protein efficiency: It quantifies how much of a protein's absorbed nitrogen is retained by the body, indicating its quality.
High BV proteins contain all nine essential amino acids: These are amino acids the body cannot produce, making them crucial for growth and tissue maintenance.
Animal proteins typically have higher BV: Eggs, meat, and dairy offer a more complete amino acid profile than most plant-based sources.
Complementary plant proteins can increase BV: Combining different incomplete protein sources (e.g., rice and beans) provides a complete amino acid profile.
BV is different from PDCAAS: PDCAAS is another scoring system that also considers digestibility, while BV focuses only on the utilization of absorbed protein.
High BV supports muscle repair and growth: High-quality protein is more effectively used to build and maintain body tissues, which is beneficial for athletes and recovery.

What Exactly is Biological Value (BV)?

Biological value (BV) is a metric that measures the proportion of absorbed protein from a food source that is then incorporated into the proteins of the body. Essentially, it quantifies how efficiently your body can use a particular protein for growth and maintenance. The BV is a key indicator of a protein's overall quality, with a higher value signifying better usability.

Proteins are composed of amino acids, and the human body requires 20 different types. Of these, nine are considered "essential" because the body cannot produce them on its own and must obtain them through diet. A protein source with a high BV contains all nine essential amino acids in the right proportions needed for bodily functions. Animal proteins, such as those found in eggs, meat, and dairy, generally have a higher BV than most plant-based proteins because their amino acid profile more closely matches human needs.

How is Biological Value Calculated?

Determining a protein's biological value typically involves measuring the amount of nitrogen retained by the body from a specific protein source. Since protein is the primary dietary source of nitrogen, this method allows scientists to calculate the proportion of protein that is actually utilized versus what is simply excreted.

The formula for calculating BV is: $$BV = (N{r} / N{a}) * 100$$ Where:

$N_{r}$ = Nitrogen retained by the body from the absorbed protein
$N_{a}$ = Nitrogen absorbed from the dietary protein

This calculation, while effective, has some limitations. It is typically conducted under controlled laboratory conditions using an artificially protein-rich diet, which may not perfectly reflect real-world scenarios. A standardized egg protein, historically assigned a BV of 100, is often used as a reference point for comparison, though its true percentage utilization is slightly lower.

Key Factors Influencing Protein's Biological Value

Several factors can affect a protein's biological value, beyond just its inherent amino acid profile:

Amino Acid Composition: The presence of all nine essential amino acids is the most critical factor. The "limiting amino acid"—the essential amino acid in the lowest proportion relative to the body's needs—will cap the protein's overall BV.
Food Preparation: Cooking and processing methods can impact the availability of amino acids. For example, excessive heat can damage or destroy certain amino acids, lowering the protein's BV.
Complementary Proteins: Combining different incomplete protein sources within a diet can create a complete amino acid profile and boost the overall BV of the meal. For instance, combining rice (low in lysine) with beans (rich in lysine) can provide a complete protein.
Health and Metabolism: An individual's age, overall health, and metabolic state can influence how efficiently protein is used. For example, those recovering from surgery or injury may have higher protein needs, which affects BV interpretation.

High Biological Value vs. PDCAAS: A Comparative Look

Over time, other methods have emerged to evaluate protein quality, each with different considerations. One notable alternative is the Protein Digestibility Corrected Amino Acid Score (PDCAAS).


Feature	Biological Value (BV)	Protein Digestibility Corrected Amino Acid Score (PDCAAS)
Primary Focus	How much absorbed protein is retained and used by the body.	Incorporates amino acid profile AND protein digestibility to create a score from 0 to 1.
Considerations	Focuses on protein usability for growth and maintenance.	Accounts for human amino acid needs (often based on a 2–5 year old child reference) and digestibility in the small intestine.
Measurement Method	Determined through nitrogen balance studies, measuring nitrogen retention versus absorption.	Compares the limiting amino acid content against a reference protein after accounting for digestibility.
Key Advantage	Offers a direct measure of how efficiently the absorbed protein is utilized.	Often considered a more practical and relevant tool for human nutrition since it includes digestibility.
Key Limitation	Does not account for variations in digestion and absorption; tests are under strict lab conditions.	The highest possible score is capped at 1.0, which can underestimate the true value of high-quality protein sources like whey.

What are the Benefits of High Biological Values?

Choosing proteins with high biological values can significantly benefit your health and fitness goals. Since the body can use these proteins more efficiently, less is wasted, leading to more effective tissue repair and growth. This is particularly important for athletes, people recovering from injuries, or older adults aiming to maintain muscle mass.

Key benefits include:

More Efficient Muscle Building and Repair: The complete profile of essential amino acids in high-BV proteins provides the necessary building blocks for synthesizing new muscle tissue after exercise or injury.
Optimized Satiety: Protein-rich foods can help you feel fuller for longer, which can support weight management efforts by reducing overall calorie intake.
Improved Overall Health: Adequate intake of high-BV protein supports numerous bodily functions, from enzyme production and hormone regulation to a robust immune system.

Conclusion

Understanding what are high biological values empowers you to make smarter dietary choices for your health. While the concept has some technical limitations compared to modern scoring systems like PDCAAS, its core principle remains valid: consuming complete proteins rich in essential amino acids is vital for your body. By prioritizing foods with high biological values, such as lean meats, dairy, and eggs, or strategically combining plant-based proteins, you can maximize your nutritional intake and support your body's repair, growth, and overall well-being. For those seeking to optimize muscle synthesis and recovery, focusing on the quality of your protein, not just the quantity, is a game-changer.

For more detailed information on protein function and quality metrics, visit the Food and Agriculture Organization of the United Nations (FAO) website.

Frequently Asked Questions

The main difference is the amino acid content. High biological value (BV) proteins contain all nine essential amino acids in the proportions your body needs, while low BV proteins are deficient in one or more essential amino acids.

Yes, chicken egg protein is often still used as a reference benchmark with a BV of 100 for historical and comparative purposes, although some modern whey proteins can have a relative BV exceeding this value.

No, you don't. By eating a varied diet and combining different protein sources throughout the day, you can get all the essential amino acids your body needs. The concept of complementary proteins, such as pairing rice and beans, helps achieve this.

No, not always. While many plant proteins are considered lower in BV because they lack certain essential amino acids, some, like soy and quinoa, are complete proteins with a high BV. Combining various plant sources can also ensure a complete amino acid intake.

Food preparation, including cooking, can affect the availability of amino acids. Excessive heat can potentially damage or destroy some amino acids, which in turn can reduce the protein's biological value.

The PDCAAS (Protein Digestibility Corrected Amino Acid Score) is often preferred because it factors in the protein's digestibility, not just its retention. It is considered a more relevant and practical measure of protein quality for human nutritional needs.

A high BV protein is more efficiently utilized for muscle synthesis and repair due to its complete amino acid profile. This makes it a high-quality source that supports muscle growth, especially in conjunction with adequate total protein intake.