Article Series

  1. Biological Value
  2. Complete Proteins

Biological Value

Biological Value
Table Of Contents
  1. What is biological value?
  2. Combination Options
  3. Conclusion

Anyone who deals intensively with proteins encounters the measure of biological value at some point. The calculation basis is now over 100 years old and is considered outdated. For a long time, it was believed that all nine essential amino acids had to be present in every meal. However, according to today's scientific principles, this is no longer necessary (see Combining Proteins?). It is perfectly adequate if the body is supplied with the essential amino acids distributed throughout the day (see protein-rich foods).

What is biological value?

The biological value can demonstrate how well the proteins from consumed foods can be converted into body protein. The more amino acids that can be converted during protein synthesis, the higher the biological value, i.e. the protein quality for humans. Since the human body is not capable of producing the nine essential amino acids itself, they must be ingested through diet. For these reasons, foods with several or all essential amino acids are also rated better than those with few. The reference value was arbitrarily set at 100 in relation to the whole egg.

Despite the outdated evaluation of proteins using biological value, we have listed some values for plant-based foods in the following table for completeness 1 2:

Plant-based foodBiological value
Soybean 96
Soy milk 91
Buckwheat 90
Quinoa 83
Rice 83
Defatted soy flour 81
Potatoes 76
Rye flour 76-83
Beans 76
Corn 76
Immature beans 65
Tofu 64
Oat 60

Combination Options

If a food has a value that is less than 100, the value can be increased by adding another food. This means that the biological value can be increased by combining different foods. If one or more combined foods have a value of 100, this means that, according to the definition, 100% of the amino acids can be used by the body. For comparison: according to current scientific knowledge, the egg cannot be converted into own proteins by the body at 100%. Therefore, the reference value itself is already incorrect.

Sensible vegan combinations for a complete protein value include:

  • Bread and sesame seeds
  • Rice and sesame seeds
  • Sunflower bread
  • Corn and soy
  • Wheat and soy
  • Wheat bread and beans
  • Beans and rice
  • Lentils and rice
  • Beans and corn


A vegan diet is usually varied. Therefore, in our opinion, it is not necessary to examine it more closely.

A newer method for evaluating amino acids is the PDCAAS method. Compared to biological value, this method also takes into account protein digestibility and absorption of amino acids in the body.