Talk:Complete protein

From Wikipedia, the free encyclopedia

Contents

[edit] Protein quality

How do these sentences: Higher quality proteins have a higher Biological Value (BV) such as whey protein at 100 BV compared to soy protein at 74 BV.[4] A higher BV is more usable than a lower BV for essential protein necessary to meet nutritional human requirements and muscle growth.[4][5][6][7][8] have anything to do with this article? I've removed them until an adequate explanation is offered. Yankees76 17:20, 5 March 2007 (UTC)

This article is about complete protein. Explaining about protein quality adds to the article. --Firstocean 17:52, 5 March 2007 (UTC)
How does quoting a couple of random facts about BV and whey protein have anything to do with Complete proteins? Yankees76 18:21, 5 March 2007 (UTC)
This explains about complete proteins differ in protein value. The information is a detailed explanantion of the difference in complete protein. You believe they are facts. I will add it back to the article. You can add as you wish. --Firstocean 01:47, 6 March 2007 (UTC)

This is the text you added:

Proteins differ in there Biological Value.[4] Higher quality proteins have a higher Biological Value (BV) such as whey protein at 100 BV compared to soy protein at 74 BV.[4][5][6][7]

Please point out where in this text there is sourced material that connects complete proteins with anything written here? How does Biological value even relate to this? It's an outdated method of measuring protein quality. The article is on complete proteins - not protein quality when measured using the biological value method. Yankees76 05:00, 6 March 2007 (UTC)

[edit] First Sentence

Older versions of this page were more correct: a complete protein need not contain "all amino acids", but it must contain the essential amino acids. Steve P. —The preceding unsigned comment was added by 70.231.128.198 (talk) 18:03, 5 March 2007 (UTC).


[edit] animal proteins are not all complete proteins

the article states that "All animal proteins are complete, including meat, poultry, seafood, eggs, and dairy". i don`t believe this is true. i don`t know how many other examples there are, but gelatine is an incomplete animal protein.

http://www.bodyforlife2.com/incompletprotein.htm http://www.answers.com/topic/gelatin?cat=health

both these sources back this up. i`m not going to edit the page as i don`t know how to add quotes

Also - Essential amino acids seems to suggest that beef is an incomplete animal protein. Thoughts? 98.160.124.227 (talk) 00:10, 1 May 2008 (UTC)

[edit] Quantity of amino acids needed to earn the "complete protein" label?

A quick check of nutritiondata.com will show the reader that almost any edible plant you search for will have all eight to ten essential amino acids. From navy beans, to brown rice, to tomatoes, to raw celery, they all have all of the EAAs in some amount, however small (for celery at least). So a complete protein clearly isn't "a protein that contains all of the essential amino acids" but rather (if most plants are to be excluded as they currently are), "a protein that contains all of the essential amino acids in a quantity sufficient to gain the label of 'complete protein.'" Where this label comes/came from, and what the milligram amounts are, I cannot discover. If anyone knows, please help this article out. 69.254.162.18 (talk) 22:40, 17 January 2008 (UTC)

You raise a good question. Judging from nutritiondata.com, it appears that it's determined "complete" if all the amino acids (9 according to nutritiondata.com) have above the "minimum amount...that should be supplied per gram of protein consumed", as determined by the Institute of Medicine. I think this means over "100" according to their protein quality scale. Interestingly, according to that website, certain animal sources are well below "100" like ground beef and yogurt, and certain plant sources are above "100", like spirulina and amaranth. Although, they don't factor in digestibility, but that doesn't have to do with the completeness of the protein, only the protein quality. -kotra (talk) 23:26, 17 January 2008 (UTC)
There are two possible incompatible ways to define an "incomplete protein": either as one in which one or more essential amino acids is absent, or as one that simply has a suboptimal amino acid composition — following some criterion of optimality.
This article first states the first definition. Later on it seems to switch to the second definition, in attempt to declare that "many plant sources" are incomplete.
The ambiguity around the definition of a complete protein encourages the absurd but widespread misconception that many in many forms of plant protein certain essential amino acids are absent. That is simply untrue, as can be seen from any table of composition. All forms of life on this planet use the same set of 20 amino acids, and almost all forms of protein contain substantial amounts of each and every one of them.
To state as this article does that only a short list of plants and "microbial sources" contain complete proteins is deeply misleading, by the first definition of an incomplete protein — the only plant source that is completely lacking in an essential amino acid is zein. It is also highly contentions by the second definition — see the article on protein combining. This article is in need of a complete rewrite.
David Olivier (talk) 21:24, 8 May 2008 (UTC)

[edit] Protein combining article in dispute

This article uses the Protein combining article to prove a point, although that article is currently in dispute. The neutrality of it and the factual accuracy of the research are disputed. See the talk section Talk:Protein_combining. These articles indicate eating a single source of protein in sufficient quantity would be give all the amino acids required, which seems a bit irresponsible. —Preceding unsigned comment added by TempestSA (talk • contribs) 12:41, 14 April 2008 (UTC)

What do you mean by irresponsible? Either the facts stated there are true or are not true. The assertions in that article are based on the figures from recognized sources.
Note that that article does not advocate eating only brown rice; if you read it that way, you have simply missed the point (you're not alone in that, so perhaps it should be explained better).
David Olivier (talk) 21:29, 8 May 2008 (UTC)


[edit] Numerical Definition of complete protein

A gram of protein is complete if it contains the following minumums:

   Tryptophan    11 mg 
   Histidine     19 mg 
   Methionine    25 mg (Cysteine can replace some of this) 
   Isoleucine    28 mg 
   Threonine     34 mg 
   Valine        35 mg 
   Lysine        58 mg 
   Phenylalanine 63 mg (Tyrosine can replace some of this) 
   Leucine       66 mg

This is from Davis & Melina, _Becoming Vegan_ Table 3.2, but is based on data adopted by both WHO and FDA, using a model called PDCAAS (Protein Digestibility Corrected Amino Acid Score).

Since the above only totals .34 grams there is quite a bit of margin.

The statements about "8-10 essential amino acids" are incorrect/misleading, as there are by convention 9 essential amino acids and two that may be used in substitution.

Spope3 (talk) 20:51, 11 May 2008 (UTC)

Concerning "8-10", various sources put the number of amino acids at either 8, 9, or 10. I used "8-10" in this article to accommodate all three views. 9 seems to be actually more potentially misleading than 8-10, since 8 and 10 are also sometimes used by sources. For example, in the first page of Google search results for "essential amino acids", all three numbers are found. But on closer examination, the most recent and credible sources, like Merck Manual and the National Academy of Sciences, the Institute of Medicine, and the Food and Nutrition Board all say 9 are essential (or "indispensable"), with up to 6 conditionally essential or indispensable amino acids in addition to the 9. So while using "9" may be not as safe as "8-10", it might be more accurate. So I have no strong opinion either way. -kotra (talk) 08:28, 12 May 2008 (UTC)