Essential amino acid requirements

River Mouse riverthemouse at hotmail.com
Mon Dec 13 11:33:23 EST 1999


"Stuart Dunn" <dunns99 at erols.com> wrote in message
news:3854C135.2428 at erols.com...
> River Mouse wrote:
> >
> > I'm reading that without an adequate balance of the eight essential
amino
> > acids, the body is incapable of synthesizing tissue from protein.
Instead,
> > surplus protein is reduced to simpler proteins for synthesizing
> > non-essential amino acids and/or converted to glucose and potentially to
> > fat.
[...]
> > What ratio are the eight essential proteins needed in? Do these ratios
> > change in repairing muscles under extreme duress, i.e. in weightlifting?
> >
> > Where can I find reference for the levels of the essential amino acids
> > contained in common foods? My particular interest is in vegan foods.
>
> It's not the ratios you need to be concerned with, it's the amounts. As
> a rule of thumb, anyone eating at least 45 grams of protein a day from
> sources other than gelatin and watermelon is safe, even if they have
> active lifestyles. Except for sweets and greasy foods, all commonly
> eaten vegan foods have "complete" proteins. Go to Walton Feed's website.
> It has more details.


This is a grossly inaccurate oversimplification. I know for a fact that many
foods are lacking in some of the 8 essential amino acids - these are the
proteins which your body CANNOT synthesize on its own.

Without all eight of the essential amino acids present, your body CANNOT do
anything with that protein except break it down to synthesize the
nonessential proteins and treat any surplus like fat.

Let's say you take 100g of each of these four protein supplements (I'm
listing supplements because I can't find Essential Amino Acid ratios for
conventional foods yet).

Whey: Cross-Flow Microfiltration Whey Protein Isolate
Soy: 90% Soy Protein Isolate
Egg: Egg White Protein Concentrate
Rice: Rice Protein Concentrate

Here's how many grams of each of these amino acids you'd get:

(You might want to change to a fixed width font for this table)

Whey | Soy | Egg | Rice | EAA
-----+-----|-----|------|----------
 6.8 | 4.3 | 4.5 |  4.2 | L-Isoleucine
10.9 | 7.2 | 6.8 |  8.6 | L-Leucine
 9.5 | 5.5 | 5.5 |  3.5 | L-Lysine
 2.5 | 1.2 | 2.7 |  2.4 | L-Methionine
 3.1 | 4.6 |  ?  |  5.2 | L-Phenylalanine
 8.3 | 3.3 | 3.6 |  3.6 | L-Threonine
 2.0 | 1.1 | 0.9 |  1.3 | L-Tryptophan
 6.4 | 4.4 | 5.1 |  4.7 | L-Valine

If methionine is the limiting factor, you'll need over twice as much soy
protein as you'd need whey protein to get the same usable EAA.

Look at lysine, and you'll see that you need about three times as much rice
as you'd need whey.

Some foods are heavier in sources than others. Since I want to rely largely
on soy sources for protein for the time being, I'm trying to find vegan
foods which are balanced in favor of lysine, methionine, threonine and
tryptophan to make up the difference. Peas and lentils are supposedly
heavier in these, so the combination of peas and soy protein may result in
something like whey's balance.

Mind you - that's -whey's- balance. I'm still looking for a source of
information on what ratios a body really needs. It may turn out that
tryptophan or one of the others isn't needed in as great a proportion.






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