Essential amino acid requirements

Tom Matthews tomatth at internet.look.ca
Mon Dec 13 23:32:25 EST 1999


Am I the only one who has noticed that the level of discourse on this
newsgroup (smn) is at an all-time low?

"Siemel B. Naran" wrote:
> 
> On Mon, 13 Dec 1999 10:33:23 -0600, River Mouse
> 
> >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.
> 
> Well, the body may burn some muscle to make up for the difference (ie, for
> whatever amino acids are lacking).  Then the protein you eat is fully usable.

That is a really asinine answer!
That is like saying that you don't need to eat at all because you can
just digest your body from the inside!

> But of course, we don't want this.

Do you really need to say that?

> >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.
> 
> If you eat twice as much soy, you get twice as much of every amino acid.
> Which means too much protein, and therefore lots of work on your kidneys
> to get rid of the excess protein/nitrogen.

"Lots of work" does not equal health problems or too much protein!
It has never been shown that high protein diets harm healthy kidneys.
Please learn some facts before answering!

> >Some foods are heavier in sources than others. Since I want to rely largely
> >on soy sources for protein for the time being,

It is unwise to rely on single or even restricted numbers of sources of
all vital nutrients.

> >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.

No, the sulfur containing amino acids (methionine/cysteine) will still
be limiting.
Grains are what you need to balance beans/legumes.

> Grains are high in methionine, and maybe the others.  So wheat cereal and
> soy milk is probably a good choice.  I use tofu in my spaghetti (because
> it tastes good to me), and this might be balance too because tofu is soy
> and sphaghetti is grain.

Now you are talking.
But is it still nowhere as good an amino acid profile as
fish/meat/dairy/whole egg is.

> >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.

Just fine a table of the RDAs for the essential amino acids and you will
have a rough indication of the ratio of body needs.
Sorry, I don't know where one is on-line and I don't have time to type
it in.

> I think whole egg has the balance the body needs.  I looked hard on
> the internet for a profile but couldn't find one (all I get are links
> to products and info that I already know -- what the essential amino
> acids are and what each one supposedly does).  Anyway, as whey protein
> has a BV of over 100 on rats, I'd say it has the right ratios.

Whole egg is one of the best available.
Actually (as I have said before) whole human is probably best, whole
monkey next and whole cow, whole chicken or whole fish not two bad.
Animal muscle meat only is not that great, because we make more than
simply muscle proteins.
But if you are body building animal muscle meat may be best of all.

--Tom 
Tom Matthews
 
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