Digestibility of Proteins
When evaluating the quality of a protein, the extent to which the protein is digested and it's amino acids are absorbed into the body are considered. If a protein has all of the essential amino acids, yet it is not efficiently digested and therefore few amino acids are absorbed into the body, it cannot be considered a high quality protein. The protein digestibility-corrected amino acid score (PDCAAS) has been the preferred method for measuring the quality of protein. This method takes into account not only the types of amino acids in the protein, but how well they are digested and absorbed into the body. The highest score is 1 and the lowest 0. The following is a list of the PDCAAS of common foods:
1.00 - Egg White
1.00 - Casein Milk Protein
1.00 - Soy Protein
0.92 - Beef
0.78 - Chickpeas
0.76 - Fruits
0.70 - Vegetables
0.59 - Cereal Grains
0.42 - Whole Wheat
It is generally thought that animal protein is more easily digested than plant protein, but you can see by the PDCAAS score that soy protein has an equivalent score to egg white. Although the PDCAAS has been used since 1991, there have been criticisms of this technique. The Food and Agriculture Organization Expert Consultation has suggested that the Digestible Indispensable Amino Acid Score (DIAAS) should replace the PDCAAS.
1.00 - Egg White
1.00 - Casein Milk Protein
1.00 - Soy Protein
0.92 - Beef
0.78 - Chickpeas
0.76 - Fruits
0.70 - Vegetables
0.59 - Cereal Grains
0.42 - Whole Wheat
It is generally thought that animal protein is more easily digested than plant protein, but you can see by the PDCAAS score that soy protein has an equivalent score to egg white. Although the PDCAAS has been used since 1991, there have been criticisms of this technique. The Food and Agriculture Organization Expert Consultation has suggested that the Digestible Indispensable Amino Acid Score (DIAAS) should replace the PDCAAS.
References
- Schaafsma G. The Protein Digestibility-Corrected Amino Acid Score. J. Nutr. July 1, 2000 vol. 130 no. 7 1865S-1867S. http://jn.nutrition.org/content/130/7/1865S.full
- FAO/WHO Expert Consultation. Protein Quality Evaluation: Food and Agriculture Organization of the United Nations, FAO Food and Nutrition Paper No. 51. Rome, Italy: Food and Agriculture Organization;1991.
Last updated April 6, 2016
