Biological Value (BV) is a metric that assesses how effectively a protein is utilized by the body for protein synthesis. It is defined as the proportion of absorbed protein that is retained for use within the organism. A high BV indicates that a food's protein has an excellent balance of all nine essential amino acids (EAAs) that the body cannot produce on its own. Animal proteins are typically considered high BV or complete proteins, while many plant proteins are incomplete, though smart food combinations can bridge this gap.
Animal-Based High Biological Value Foods
Animal products are well-known for their high biological value due to their complete and balanced amino acid profiles, which closely match human requirements. These proteins are a primary source of EAAs for many diets.
Here is a list of some of the best animal-based sources:
- Eggs: Often considered the gold standard of protein quality, with an assigned biological value of 100. This is because eggs contain a perfect ratio of essential amino acids that are highly bioavailable to the body.
- Milk and Dairy Products: Milk protein, composed of both casein and whey, offers an excellent EAA profile that is highly digestible and utilized efficiently. Cheeses, yogurt, and specialized whey protein concentrates also boast high BV.
- Meat, Poultry, and Fish: These sources consistently provide complete proteins with high BV, typically scoring in the 80–90 range. Examples include chicken breast, beef, and salmon. The quality can be influenced by processing and cooking methods.
Plant-Based High Biological Value Foods
Historically, plant proteins were considered inferior to animal proteins because most individual sources are missing or low in one or more EAAs. However, this perspective is outdated, as some plant foods are complete proteins, and combining different plant sources strategically can create a complete amino acid profile.
Some high-BV plant sources and combinations include:
- Soy and Soy Products: Edamame, tofu, and soy milk are excellent plant-based protein sources, containing all EAAs. Their BV is high, comparable to some animal sources.
- Quinoa: This pseudocereal is a standout among plant-based foods as it is a complete protein, offering a comprehensive spectrum of EAAs.
- Buckwheat: Like quinoa, buckwheat is a pseudocereal that provides all essential amino acids, making it a valuable complete protein source.
- Combined Complementary Proteins: Many traditional vegetarian cuisines rely on combining different plant foods to achieve a complete protein. A classic example is combining grains (like rice) with legumes (like beans). Other pairings include peanut butter with bread and lentils with buckwheat.
Understanding Biological Value (BV) vs. Other Metrics
While BV is a useful indicator of protein quality, it is not the only metric used by nutrition scientists. Other assessment tools provide a more comprehensive picture by also considering digestibility.
- BV Focus: Measures the percentage of absorbed protein retained by the body, so it doesn't account for digestibility. This means a protein that is perfectly utilized but poorly digested will still have a higher BV than a highly digestible, but slightly less balanced protein.
- PDCAAS (Protein Digestibility Corrected Amino-Acid Score): Developed by the FAO/WHO, this score compares a protein's EAA profile to a reference pattern, then corrects for fecal digestibility. It was the standard until recently.
- DIAAS (Digestible Indispensable Amino Acid Score): The newer, recommended metric, DIAAS, measures the digestibility of individual amino acids at the end of the small intestine, providing a more accurate score than PDCAAS.
For a detailed analysis, these newer metrics offer a more nuanced look at protein quality. However, for general dietary purposes, a high BV score is a strong indicator of quality protein.
High Biological Value Food Comparison Table
| Food Source | BV (approx.) | Type | Notes |
|---|---|---|---|
| Whole Egg | 100 | Animal | Benchmark for perfect EAA profile. |
| Whey Protein | >100 (relative) | Animal | Extremely high quality, often used in supplements. |
| Milk | 91 | Animal | Balanced mix of casein and whey proteins. |
| Fish | 76 | Animal | Generally very high-quality protein. |
| Beef | 74 | Animal | High BV, but can be slightly lower than other animal sources. |
| Soybeans | 74 | Plant | Complete protein source, excellent plant-based option. |
| Quinoa | 83 | Plant | A rare complete plant protein with all EAAs. |
| Rice + Beans | >100 (combined) | Plant | Complementary combination for high BV. |
Maximizing Protein Utilization
To ensure your body is effectively using the protein you consume, consider these tips, especially if you follow a plant-based diet:
Protein Complementation
Pairing different plant proteins is a simple way to get a full spectrum of essential amino acids. While your body can store amino acids and doesn't require all EAAs in a single meal, combining them can be beneficial. Legumes (like beans and lentils) are often low in methionine but rich in lysine, while grains (like rice and wheat) are rich in methionine but low in lysine. Combining them creates a complete profile.
Prioritize Variety
Eating a wide range of protein sources throughout the day, both from animal and plant foods, naturally ensures you receive a balanced intake of all EAAs. This prevents an over-reliance on a single, potentially incomplete source.
Consider Cooking Methods
While less important for BV than amino acid composition, some cooking methods can affect protein availability and overall digestibility. For example, soaking and cooking legumes properly improves their digestibility and protein absorption.
Link to a Reliable Resource
For those interested in the scientific assessment of protein quality, you can explore detailed methodologies and scoring systems on the National Institutes of Health website.
Conclusion
Understanding what foods are high in biological value is fundamental to building a healthy diet rich in high-quality protein. While animal sources like eggs, milk, and meat are natural complete proteins, excellent plant-based options like soy and quinoa exist. For vegetarians and vegans, strategically combining complementary proteins ensures a complete EAA profile. By focusing on a diverse range of high BV foods, you can optimize your body's ability to build and repair tissues, support metabolic functions, and maintain overall health.
