Hi!

They say "the best proteinsource is leafy veggies". Why? Is it because they got a higher amount of free amino acids in them? Or is it because the complex proteins just break up easier in the intestines?

Anyone got any answers to this?

// Bun

Yes, you are correct. They do contain a high amount of amino acids,thus having a high caloric percentage.But greens are so low in total calories,that the body won't get toxic amounts of protein...in other words,leafy greens provide a small amount of high quality protein. Plus the fact that leafy greens are almost always eaten raw keeps them in an unaltered natural state.

Thanks Dove!

But does anybody seen some testresults what amount the free amino acids are compared to the already structured proteins? 50%? 90?

I believe that most,if not all the protein in leaves and all vegetables are stuctured. Only ripe fruits contain free form amino acids. However,the proteins in leafy greens are disassembled and reassembled very easy. Much easier than the denser proteins found in seeds and animal tissue....Sorry,I don't have the percentages that you seek.

Thanks Dove, I love you anyway

C Dove, I'd thought that all plant proteins were chains of amino-acids that our bodies had to break down before using and haven't to date found anything to suggest that fruit was an exception to this rule.

Could you please tell me more, or where you have read this?

I actually thought this was common knowledge. Fruits ripen.Some do on the plant and some continue after they are picked. When they are green they contain a lot of digestive enzymes and they are not sweet. As they ripen,the enzymes break the starch into simpler sugars,the protein into amino acids,and the fat into fatty acids. This is why ripe fruits are so digestable. If you find any evidence to dispute this,please advise me.

C Dove. If it were common knowledge, I wouldn't be asking, would I? :-) Also, this subject has come up on various forums in the past.

I have been trying to get to the bottom of this for some time. For example, I discussed this with a Masters Chemistry student a while back and she said that it simply isn't the case that there are 'amino acids' in plant foods just 'floating around', ours for the taking, ie that we still have to break down the proteins. I do think if fruit were different she would have said (she knows I follow a high-fruit diet!).

And this is my point. Some non-scientific writers give the impression that our bodies can simply 'absorb' the amino-acids from 'plant foods generally' and not have to do any work. Yet whenever I raise this with anyone with any knowledge of chemistry, they tell me this is not the case.

I just read your message to my Nutrition BSC undergraduate son, and he feels similarly.

Re fruit, we're all fine with the part about starch changing into sugar. Yes, that's certainly the case, and the reason I have always understood that fruits are more easily digested, ie the sugar, being in monosaccharide form, can be absorbed directly rather than the body having to break it down.

But proteins broken down into amino acids so our body doesn't need to break anything down? Joe (student son) said something that made sense to me - the fruit, despite ripening, would still need its structural proteins. He also thought that new proteins might form during ripening.

Are you saying all the proteins are broken down in ripening, or are you saying that just some of them are broken down? If you're saying just some of them, then perhaps we are talking at cross-purposes. And if so, what percentage of the amino-acids in fruit are 'free'? And which ones are they?

Last time I delved into this (there was a thread on here on similar a few weeks ago) I googled extensively and couldn't find anything definitive on it.

(Sorry, C Dove, having scanned the replies above, ignore the query about percentages - see now you don't have this information).

Debbietook, I aplogize if I sounded offensive too you. And I am impressed with your enthusiasim on this subject. Like me,you have a scientific need to know the "why" and "how" of things. Since I read your post I have been looking for a scientific expanation myself. However,I did fnd something that could be related to this question. If this study answers your question,then the conversion to free form amino acids is only partial,but significant. Perhaps we both can learn something new here. I am very scientific,and rarely except something simply because a "guru" says so. If you can cite a study disputing this claim,I will change directions,glady.....I would like to hear what your thoughts are on this link: [books.google.com]

Debbie,do you know about the "30 bananas a day" site? You might get some good info on that board.... I might ask this question on that site.

[arawconnection.ning.com]

Giving it a thought, There MUST be some content of free amino acids in a plant. For example, in biology-class in school we look at cells split and grow at the tips of roots.

For the plant to actually grow bigger leaves etc. there must be some amino acids (flowing to the edge of the leaves to be structured there to proteins. Or where do leaves actually grow? At the root to the leaf?

Then there might be a teoretical % at 1 with free amino acids.

The other thought is that there excists no amino acids and proteins just appear behind a flashy curtain of love and light. :-)

I found more links:

[www.ajevonline.org]


[www.hortnet.co.nz]

[www.ncbi.nlm.nih.gov]

Thanks C. Dove and Healthy Bun (C. Dove - doh - I'm on 30Ban - haven't you noticed me? :-) There again, I've been a bit quiet lately). C Dove - very appreciate the time you've taken.

Bit hectic over next couple of days but I will most definitely follow up those links, and agree that we might both add to the 'pool of knowledge' here! Will be back soon.



Edited 1 time(s). Last edit at 03/26/2009 05:11PM by debbietook.

Healthybun Wrote:
-------------------------------------------------------
> Giving it a thought, There MUST be some content of
> free amino acids in a plant. For example, in
> biology-class in school we look at cells split and
> grow at the tips of roots.
>
> For the plant to actually grow bigger leaves etc.
> there must be some amino acids (flowing to the
> edge of the leaves to be structured there to
> proteins. Or where do leaves actually grow? At the
> root to the leaf?
>
> Then there might be a teoretical % at 1 with free
> amino acids.
>
> The other thought is that there excists no amino
> acids and proteins just appear behind a flashy
> curtain of love and light. :-)

..I think you are right, Healthybun. At any time in a plants growth a small % of amino acids will be in their "free" state allowing synthesis of proteins for root and leaf growth, and eventually fruit and seed production.

The term "free amino acid" seems to be used loosely even in the scientific papers, and especially by the supplement industry, as if the term somehow implies it is better than plain old 'amino acids'.

Leafy greens like spinach have a particularly high % of calories from protein and so have that reputation of being a good source; "free amino acids" referring perhaps more to the spectrum of essential amino acids it contains, more than the degree to which the proteins are separated into individual amino acids, imo.

peace and love



Edited 1 time(s). Last edit at 03/26/2009 05:55PM by loeve.

Did you find those links, C Dove?

..this looks like it could be a typical plant leaf cell, so it would be encased in cellulose walls?, and so bioavailability of the protein inside would depend on how well it is chewed, juiced or blended. By the way, the vacuole in the diagram is the cell's storehouse -- each cell has a large, single vacuole that stores compounds and helps in plant growth.




Edited 1 time(s). Last edit at 03/27/2009 01:16AM by loeve.

> ... flowing to the edge of the leaves to be structured there to
> proteins...

..this image helped me get a better idea of the leaf's vascular system (veins), and an idea where the protein is within a leaf; i.e. inside the cells of the epidermis, mesophyll cells and veins. So, plants manufacture their own amino acids to assemble proteins and then cells use that to grow and share with other plant parts thru veins.



[search.aol.com]



Edited 1 time(s). Last edit at 03/27/2009 12:33PM by loeve.

Mmm. Botany. I loved that class. Wish I took the second semester.

Google rubisco. It's the most abundant protein on the planet.

Don't worry about free aminos. Your GI tract will break down the helix, chain, sheet, or glob.

PS rubisco, AKA ribulose-1,5-bisphosphate carboxylase/oxygenase is a glob.