Essential amino acid requirements

Tom Matthews tomatth at internet.look.ca
Mon Dec 13 23:13:48 EST 1999


You see, Stuart!
Even the person asking the question knows more than you!
Talk about the "blind leading the blind"!!!

--Tom

River Mouse wrote:
> 
> "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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