Protein combining?

My food technology teacher told the class that vegetarians have to combine multiple types of amino acids in one meal in order to get a complete protein. I was under the impression that this theory had been disproven.. Is there any evidence supporting it or negating it?

i used to believe it too.

 

then i did some research. it has been disproven.

 

 

i thought you were pro-meat?

Yes, I do believe meat eating can be as healthy as vegetarianism.

The reason I ask this question is because I feel my teacher isn't all that informed and it annoys me when a teacher acts as if I am the ignorant one.

if i were in your situation, i would find a nice respected website that proves he is wrong. what does your textbook say?

yeah people used to believe that but it's been proven wrong. your body does all the "completing the protein" stuff on its own. you don't have to worry about getting different types every time you eat.

Cool, I just read a website yesterday touting this theory... anybody have any links to a site that disproves it?

The China Study discusses this.  Start here.

Yea, it's a myth.   Here's a couple of links:

McDougall.

PCRM. (see #4)

Original Post by bbnomo:

Yea, it's a myth.   Here's a couple of links:

McDougall.

PCRM. (see #4)

I found it interesting that McDougall on the bottom of the page seems to disagree with what we call 'starvation mode' - saying that the Irish men who died, had a huge loss in FAT and kept most of their muscle.  Interesting.   Anyhow this thread was interesting because I didn't know the answer to the Q myself!

 I think that saying this is a "myth" is somewhat misleading.  I'm finishing my masters degree in exercise physiology (a branch of kinesology that includes a lot of nutrition emphasis), so while I'm not an expert I've had some experience with this.  Of the 20 amino acids, 9 cannot be made by your body and must come from your diet (these are the "essential" amino acids).  All plant proteins (with the exception of soy) are incomplete, meaning that they lack at least one essential amino acids.  The idea that you should combine proteins suggests that you should eat complimentary proteins (like rice and beans, for example) to meet your complete protein needs.  I'm not sure that you'd have to combine proteins in a single meal as long as you do over the course of the day.  

In looking at the linked websites, it seems like the authors are refuting the idea that you can't get enough complete protein from non-animal sources.  You can surely get enough protein from non-animal sources, you just need to make sure you're eating complimentary non-animal proteins.  The second website (PCRM) suggests that one should eat a variety of fruits, veggies, legumes, and whole grains, which will ensure that your proteins are complimentary. As long as your diet is varied, you don't have to plan out which proteins will compliment one another.  Also, any soy-based food will have complete protein because soy is the only complete non-animal protein.

I hope that made sense and helped to answer the question.  Feel free to message me or reply with other questions!  :)

I think you are just citing as truth the very myth that everyone else already debunked... ??

 

http://www.drmcdougall.com/misc/2007nl/apr/da iry.htm has a list of vegetables that provide all of the essential amino acids. 

 

 1.  Any RD worth his/her credentials will tell you to vary your plant intake to ensure adequate essential amino acid comsumption.

 2.  The list of "complete" plant proteins on the linked website only cite 8 amino acids, not 9.....where is histadine?  (see http://en.wikipedia.org/wiki/Essential_amino_ acids)

3.  See also http://www.veganhealth.org/articles/protein   Here is an excerpt, "Non-soy plant proteins have a lower percentage of at least one amino acid (in particular, beans are lower in methionine and grains are lower in lysine)...Some people are under the impression that some plant proteins are devoid of at least one essential amino acid. The truth is that all plant proteins (that I have looked up) have some of every essential amino acid."  You would have to eat a whole lot of beans to get the amount of methionine your body requires.

4.  I would be really interested to see the actual study in which two participants ate nothing but potatoes for 6 months (cited at http://www.drmcdougall.com/misc/2007nl/apr/da iry.htm).  No self-respecting scientific journal would EVER publish a study done on only TWO people and present it as scientifically relevant.  Case studies (reports of the findings on a single subject) are usually published when the single subject has a response that is very different from the normal population.  Also, I would be curious to know what "in good health" means by today's technological standards instead of the standards available in 1925.  What about nitrogen balance?  For a search of the modern age's relevant research, try searching at http://www.ncbi.nlm.nih.gov/sites/entrez

5.  Here is some nutritional info from sources I actually trust:

http://www.feinberg.northwestern.edu/nutritio n/factsheets/protein.html

http://www.hsph.harvard.edu/nutritionsource/p rotein.html

http://en.wikipedia.org/wiki/PDCAAS

http://www.fao.org/docrep/U5900t/u5900t07.htm

http://www.jssm.org/vol3/n3/2/v3n3-2pdf.pdf

 

The point is that it is not necessary to combine multiple types of amino acids in one meal, but that one can eat a healthy vegan diet consisting of a variety of whole plant foods to provide oneself with all of the essential proteins in quantities necessary for good health.

In other words, vegans eating rice WITHOUT beans (or visa versa) IS okay.

Here's another discussion of the subject, with nitrogen balance study references.

Eat a wide variety of plant based foods and don't worry about it.  You'll get all the essential amino acids your body needs.  Meal planning gymnastics are not required.

Yeah, i was told the same thing over and over and I'm studying to be an RD. 

This is only important if you are not eating a good variety of plant based foods.  For example, vegans who are uneducated about proper nutrition and eat the same few things over and over again.  If you don't vary your diet you can compromise your immune system and will probably have colds all the time.  

 But if you've taken a nutrition class  then you probably know this anyways.