Complete protein

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A complete protein or whole protein is a food source of protein that contains an adequate proportion of each of the nine essential amino acids necessary in the human diet.[1] Examples of single-source complete proteins are red meat, poultry, fish, eggs, milk, cheese, yogurt, soybeans and quinoa.[2][3][4] The concept does not include whether or not the food source is high in total protein, or any other information about that food's nutritious value.

It was once thought that plant sources of protein are deficient in one or more amino acids, and so vegetarian diets had to specifically combine foods during meals, which would create a complete protein. However, the most recent position of the Academy of Nutrition and Dietetics is that protein from a variety of plant foods eaten during the course of a day typically supplies enough essential amino acids when caloric requirements are met.[5] Normal physiological functioning of the body is possible if one obtains enough protein and sufficient amounts of each amino acid from a plant-based diet.[6] In fact, the highest PDCAAS scores are not given to commonly eaten meat products, but rather to animal-derived vegetarian foods like milk and eggs and the vegan food soy protein isolate.[citation needed]

Optimal amino acid profile[edit]

The following table lists the optimal profile of the nine essential amino acids in the human diet, which comprises complete protein, as recommended by the Institute of Medicine's Food and Nutrition Board:[2][7](note that the examples have not been corrected for digestibility)

Essential amino acid mg/g of protein percentage of total protein raw, whole chicken egg[8][9] quinoa[10] raw spinach[11]
Tryptophan 7 0.7% 1.33% 1% 1.36%
Threonine 27 2.7% 4.42% 3.2% 4.27%
Isoleucine 25 2.5% 5.34% 4.2% 5.14%
Leucine 55 5.5% 8.65% 7.3% 7.8%
Lysine 51 5.1% 7.27% 6.1% 6.08%
Methionine+Cystine 25 2.5% 5.18% 2.7%+1.3% 1.85%+1.22%
Phenylalanine+Tyrosine 47 4.7% 9.39% 4.3%+3.6% 4.51%+3.78%
Valine 32 3.2% 6.83% 5% 5.63%
Histidine 18 1.8% 2.45% 3.1% 2.24%
Total 287 28.7% 50.86% 41.8% 43.88%

Total adult daily intake[edit]

The second column in the following table shows the amino acid requirements of adults as recommended by the World Health Organization[12] calculated for a 62 kg (137 lb) adult. Recommended Daily Intake is based on 2,000 kilocalories (8,400 kJ) per day,[13] which could be appropriate for a 70 kg (150 lb) adult.

Essential amino acid Required mg/day for a 62 kg (137 lb) adult
Tryptophan 248
Threonine 930
Isoleucine 1240
Leucine 2418
Lysine 1860
Methionine+Cystine 930
Phenylalanine+Tyrosine 1550
Valine 1612
Histidine 620
Total 11,408 milligrams (11.408 g)
Total Protein 46 to 56 grams (46,000 to 56,000 mg)

Sources of complete protein[edit]

See also[edit]


  1. ^ a b "Protein in diet". Medline Plus Medical Encyclopedia. U.S. National Library of Medicine and National Institute of Health. September 2, 2003. Retrieved 2006-10-28. In the published meta-analysis of nitrogen balance studies by Rand and coworkers (2003), there were no significant differences in the intakes of dietary nitrogen required to meet nitrogen equilibrium between those studies that supplied dietary protein predominantly from animal, vegetable, or mixed protein sources. It is important to realize, however, that this aggregate analysis does not suggest that dietary protein quality is of no importance in adult protein nutrition. ... the quality of well-processed soy proteins was equivalent to animal protein ... while wheat proteins were used in significantly lower efficiency ... while lysine is likely to be the most limiting of the indispensable amino acids in diets based predominantly on cereal proteins, the risk of a lysine inadequacy is essentially removed by inclusion of relatively modest amounts of animal or other vegetable proteins, such as those from legumes and oilseeds, or through lysine fortification in cereal flour.
  2. ^ a b c Food and Nutrition Board of Institute of Medicine (2005) Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids [1], page 691, from National Academies Press
  3. ^ "All About the Protein Foods Group". US Department of Agriculture. 3 November 2017. Retrieved 20 May 2018.
  4. ^ "Quinoa: An ancient crop to contribute to world food security" (PDF). Food and Agriculture Organization. July 2011. Retrieved 14 July 2018.
  5. ^ Melina, Vesanto; Craig, Winston; Levin, Susan (2016-12-01). "Position of the Academy of Nutrition and Dietetics: Vegetarian Diets". Journal of the Academy of Nutrition and Dietetics. 116 (12): 1971. doi:10.1016/j.jand.2016.09.025. ISSN 2212-2672. PMID 27886704 – via
  6. ^ Young VR, Pellett PL (1994). "Plant proteins in relation to human protein and amino acid nutrition". American Journal of Clinical Nutrition. 59 (5&nbsp, Suppl): 1203S–1212S. doi:10.1093/ajcn/59.5.1203s. PMID 8172124.CS1 maint: Uses authors parameter (link)
  7. ^ "Protein quality"., Conde Nast. 2014. Retrieved 20 May 2018.
  8. ^ "Amino Acid Profile for Egg, whole, raw, fresh". Retrieved 2018-08-07.
  9. ^ "Egg, whole, raw, fresh Nutrition Facts & Calories". Retrieved 2018-08-07.
  10. ^ "Quinoa Amino Acid Profile". Retrieved 2018-08-07.
  11. ^ Vanovschi, Vitalii. "Spinach, raw: nutritional value and analysis". Retrieved 2018-08-07.
  12. ^ World Health Organization, Protein and Amino Acid Requirements in Human Nutrition, p. 245
  13. ^ "Guidance for Industry: A Food Labeling Guide". U.S. Food & Drug Administration. US FDA. Retrieved 14 January 2017.
  14. ^ "Quinoa: An emerging "new" crop with potential for CELSS (NASA Technical Paper 3422)" (PDF). NASA. November 2003. Retrieved 2006-10-28.