From: Harvey Newstrom (mail@HarveyNewstrom.com)
Date: Tue May 14 2002 - 12:45:13 MDT
On Tuesday, May 14, 2002, at 01:10 pm, Al Villalobos wrote:
> Also remember that vegetable protein is not as efficiently converted to
> animal protein. The general rule of thumb is only about 70%
> conversion. So
> it would take 130g of soy protein to have the same effect as 100g of
> egg or
> beef protein(actually egg is the reference standard for human protein
> absorption)
>
> AL
This is not quite true, but as usual the issue is confusing. Animal
proteins are fully formed proteins which are broken down in the stomach
and then reassembled in the body. As such, animal protein is harder to
digest than vegetable protein. Individual amino acids are sometimes
called "predigested" amino acids because they do not have to be broken
down from more complex proteins. Veggie proteins are closer to
"predigested" than animal proteins.
What I believe you are thinking about is the fact that animal proteins
are more "complete" proteins, meaning they contain a combination of
various amino acids that is closer to human requirements than
vegetables. That is because we are more closely related to animals on
the evolutionary scale, and animal flesh is closer to human flesh than
plant flesh would be. A human has to eat various plant sources of
protein to assemble the right balance of amino acids, or else excessive
aminos in one group are wasted because of a deficiency of aminos in
another group.
It used to be believed that it vegetable proteins had to be eaten in the
right combination at the same time to form protein. This lead to the
belief that vegetable protein was hard to get than animal protein. This
has since been proven false. The human body absorbs individual amino
acids just fine, and seems to hold them for a few days so that they can
combine with other amino acids. Food combining is not required every
day, as long as a varied diet is achieved over a week. Evidence shows
that the body is very efficient at eating different foods at irregular
intervals and still managing to combine the proper building blocks to
function.
Even if what you said were still valid, modern food measuring and
labeling is adjusted so that we show actual nutrient availability and
not raw content. Food values have been adjusted so that differences in
absorption and bioavailability are accounted for. So equivalent
nutrient contents on labels should really be equal for most purposes.
For example, Alpha-tocopherol vitamin E is easier to absorb and use than
Gamma-tocopherol, but food labels are skewed to account for this
difference. Foods with the same vitamin E levels are nutritionally
equivalent because the foods with gamma-tocopherol contain higher
amounts to achieve that nutritional rating than foods containing
alpha-tocopherol which contain lesser amounts to achieve the same
nutritional rating. Although alpha-tocopherols are more potent than
other forms, all foods labeled with the same vitamin E content are
equivalent regardless of which form of vitamin E they contain.
-- Harvey Newstrom, CISSP <www.HarveyNewstrom.com> Principal Security Consultant <www.Newstaff.com>
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