Digestible Indispensable Amino Acid Score

Digestible Indispensable Amino Acid Score (DIAAS) is a protein quality method proposed in March 2013 by the Food and Agriculture Organization to replace the current protein ranking standard, the Protein Digestibility Corrected Amino Acid Score (PDCAAS).

The DIAAS accounts for amino acid digestibility at the end of the small intestine, providing a more accurate measure of the amounts of amino acids absorbed by the body and the protein's contribution to human amino acid and nitrogen requirements. This is in contrast to the PDCAAS, which is based on an estimate of digestibility over the total digestive tract. Values stated using this method generally overestimate the amount of amino acids absorbed.^[1]

Reference pattern

Amino acid requirements were determined in two parts. The amino acid distribution of breast milk was used for the 0 to 6 month age range, and existing amino acid data was used for older ages after adjustment for digestibility. The reference amino acid requirements are presented below.^[2]: 29

	Requirements by age (mg/g protein)
Amino acid	0 to 6 months	6 months to 3 years	Over 3 years
Histidine	21	20	16
Isoleucine	55	32	30
Leucine	96	66	61
Lysine	69	57	48
Methionine + Cysteine (SAA)	33	27	23
Phenylalanine + Tyrosine (AAA)	94	52	41
Threonine	44	31	25
Tryptophan	17	8.5	6.6
Valine	55	43	40

Example values

The table shows the ratings of selected foods comparing PDCAAS to DIAAS.^{[3][4][5][6][7][8][9][10][11][12][13][14]} The quality of various sources of protein depends on how it is processed, refined, stored, or cooked.^[12][15][16] (preparation is unspecified for some values in the table, but does not necessarily differ in preparation from the foods where preparation is specified). A major difference between DIAAS and PDCAAS, is that PDCAAS is truncated at 100%, while DIAAS is not. Multiple protein sources can also be combined to increase DIAAS, which can be effective at raising the max DIAAS of plant-based diets.^[13]

Food	PDCAAS	DIAAS for 0.5-3 yo[13]	Limiting AA
Milk Protein Concentrate[3][4]	1.00	1.18	Met + Cys
Whey Protein Isolate[3][4]	1.00	1.09	Val
Soy Protein Isolate[3][4]	0.98	0.898	Met + Cys
Pea Protein Concentrate[3][4]	0.893	0.822	Met + Cys
Rice Protein Concentrate[3][4]	0.419	0.371	Lys
Whole milk powder[5]	1.000	1.159
Tilapia[17]		1.00
Tuna (canned in oil)[16]	1.00
Chicken breast[3]	1.00	1.08	Trp
Pork[13]		1.17
Beef[5]	1.000	1.116
Whole milk[3]	1.00	1.14	Met + Cys
Egg (hard boiled)[3]	1.00	1.13	His
Egg[13]		1.01
Chickpeas[3]	0.74	0.83	Met + Cys
Tofu[3]	0.70	0.97	Met + Cys
Peas[5]	0.782	0.647
Cooked peas[3][4]	0.597	0.579	Met + Cys
Soybean[5]	1.000	0.996
Soy[13]		0.91	Met + Cys
Soya Flour[14]	1.00	1.05
Fava Bean[13]		0.55	Met + Cys
Cooked kidney beans[4]	0.648	0.588
Roasted peanuts[4]	0.509	0.434
Almonds[3]	0.39	0.40	Lys
Wheat[5][13]	0.463	0.40-0.48
Wheat flour[16]	0.40
Wheat bran[5][4]	0.53-0.60	0.41-0.49
Barley[5]	0.591	0.472
Rye[5]	0.553	0.476
Triticale[5]	0.553	0.498
Corn[13][16]	0.37	0.36	Met + Cys
Corn Grain[5]	0.473	0.424
Corn-based cereal[3][4]	0.078	0.012	Lys
Rice[13]		0.47	Lys
Cooked rice[3][4]	0.616	0.595	Lys
Oats[13]		0.57	Lys
Cooked rolled oats[4]	0.670	0.542
Potato[13]	0.99	1.00
Quinoa[11]	0.677
Quinoa flour[16]	0.79
Gelatin[13]		0.02	Trp
Wheat/potato (30/70)[13]		1.00
Vegetables[18]	0.73-0.89
Tubercles[18]	0.74-0.89
Fresh Fruits[18]	0.64-0.76
Dried Fruits[18]	0.48-0.66
Legumes[18]	0.70-0.89

Comparing DIAAS to PDCAAS

• The PDCAAS uses the faecal digestibility while the DIAAS considers the ileal digestibility.
• The PDCAAS is truncated at 100% while DIAAS is not
• The PDCAAS experimentation protocol that determines the digestibility involves rats while the DIAAS advises to use pigs preferably as the pig digestive system is closer to the human's system.
• The PDCAAS considers the global digestibility of the product's protein (a single figure) while the DIAAS accounts for a specific digestibility percentage for each indispensable amino acid
• The reference values for the PDCAAS are based on a unique age group, the 2 to 5-year-old child which is deemed to be the more demanding. The DIAAS provides values for three different age groups, with more up to date data about human needs.

See also

• Amino acid score
• Protein Digestibility Corrected Amino Acid Score
• Protein quality
• Net protein utilization
• Nitrogen balance
• An app that helps calculate the DIAAS value of a mix of food items

References

1. "FAO proposes new protein quality measurement. March 2013". Archived from the original on 2017-05-19. Retrieved 2016-05-10.
2. FAO (2013). Dietary protein quality evaluation in human nutrition (PDF). Food and Agriculture Organization of the United Nations. ISBN 978-92-5-107417-6. Archived (PDF) from the original on 2022-10-09. Retrieved 2021-10-10.
3. Phillips SM (2017-05-08). "Current Concepts and Unresolved Questions in Dietary Protein Requirements and Supplements in Adults". Frontiers in Nutrition. 4: 13. doi:10.3389/fnut.2017.00013. PMC 5420553. PMID 28534027.
4. Rutherfurd SM, Fanning AC, Miller BJ, Moughan PJ (February 2015). "Protein digestibility-corrected amino acid scores and digestible indispensable amino acid scores differentially describe protein quality in growing male rats". The Journal of Nutrition. 145 (2): 372–379. doi:10.3945/jn.114.195438. PMID 25644361. S2CID 28977517.
5. Ertl P, Knaus W, Zollitsch W (November 2016). "An approach to including protein quality when assessing the net contribution of livestock to human food supply". Animal. 10 (11): 1883–1889. Bibcode:2016Anim...10.1883E. doi:10.1017/S1751731116000902. PMID 27160573.
6. Hoffman JR, Falvo MJ (September 2004). "Protein - Which is Best?". Journal of Sports Science & Medicine. 3 (3): 118–130. PMC 3905294. PMID 24482589.
7. House JD, Neufeld J, Leson G (November 2010). "Evaluating the quality of protein from hemp seed (Cannabis sativa L.) products through the use of the protein digestibility-corrected amino acid score method". Journal of Agricultural and Food Chemistry. 58 (22): 11801–11807. doi:10.1021/jf102636b. PMID 20977230.
8. Mathai JK, Liu Y, Stein HH (February 2017). "Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)". The British Journal of Nutrition. 117 (4): 490–499. doi:10.1017/S0007114517000125. PMID 28382889. S2CID 22644521.
9. Zarkadas CG, Yu Z, Hamilton RI, Pattison PL, Rose NG (January 1995). "Comparison between the Protein Quality of Northern Adapted Cultivars of Common Maize and Quality Protein Maize". Journal of Agricultural and Food Chemistry. 43 (1): 84–93. doi:10.1021/jf00049a016. ISSN 0021-8561.
10. Phillips SM (2016-09-29). "The impact of protein quality on the promotion of resistance exercise-induced changes in muscle mass". Nutrition & Metabolism. 13 (1): 64. doi:10.1186/s12986-016-0124-8. PMC 5041535. PMID 27708684.
11. Ruales J, de Grijalva Y, Lopez-Jaramillo P, Nair BM (March 2002). "The nutritional quality of an infant food from quinoa and its effect on the plasma level of insulin-like growth factor-1 (IGF-1) in undernourished children". International Journal of Food Sciences and Nutrition. 53 (2): 143–154. doi:10.1080/09637480220132157. PMID 11939108. S2CID 12001819.
12. Nosworthy MG, Medina G, Franczyk AJ, Neufeld J, Appah P, Utioh A, et al. (May 2018). "Effect of Processing on the In Vitro and In Vivo Protein Quality of Beans (Phaseolus vulgaris and Vicia Faba)". Nutrients. 10 (6): 671. doi:10.3390/nu10060671. PMC 6024599. PMID 29799474.
13. Herreman L, Nommensen P, Pennings B, Laus MC (October 2020). "Comprehensive overview of the quality of plant- And animal-sourced proteins based on the digestible indispensable amino acid score". Food Science & Nutrition. 8 (10): 5379–5391. doi:10.1002/fsn3.1809. PMC 7590266. PMID 33133540.
14. Mathai JK, Liu Y, Stein HH (February 2017). "Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)". The British Journal of Nutrition. 117 (4): 490–499. doi:10.1017/S0007114517000125. PMID 28382889. S2CID 22644521.
15. Bailey, Hannah M.; Mathai, John K.; Berg, Eric P.; Stein, Hans H. (July 2020). "Most meat products have digestible indispensable amino acid scores that are greater than 100, but processing may increase or reduce protein quality". British Journal of Nutrition. 124 (1): 14–22. doi:10.1017/S0007114520000641. ISSN 0007-1145. PMID 32089140. S2CID 211261687.
16. Boye, Joyce; Wijesinha-Bettoni, Ramani; Burlingame, Barbara (August 2012). "Protein quality evaluation twenty years after the introduction of the protein digestibility corrected amino acid score method". British Journal of Nutrition. 108 (S2): S183 – S211. doi:10.1017/S0007114512002309. ISSN 0007-1145. PMID 23107529.
17. Burd, Nicholas A.; Beals, Joseph W.; Martinez, Isabel G.; Salvador, Amadeo F.; Skinner, Sarah K. (2019-02-01). "Food-First Approach to Enhance the Regulation of Post-exercise Skeletal Muscle Protein Synthesis and Remodeling". Sports Medicine. 49 (1): 59–68. doi:10.1007/s40279-018-1009-y. ISSN 1179-2035. PMC 6445816. PMID 30671904.
18. Suárez López, M. M.; Kizlansky, A.; López, L. B. (January 2006). "[Assessment of protein quality in foods by calculating the amino acids score corrected by digestibility]". Nutricion Hospitalaria. 21 (1): 47–51. ISSN 0212-1611. PMID 16562812. Archived from the original on 2022-03-31. Retrieved 2022-03-31.