From:
steve austin
Date: 2001-03-12 21:49:00 UTC
Subject: plant vs. animal proteins
Someone asked the difference between plant and animal proteins. O.K., if
you are not interested, just delete now. Or the moderators can do so if
this is too off topic. I find this stuff interesting and a friend has a
PhD in nutrition, so I love to ask him questions, his wife has PhD in
biochemistry. Great people! Maybe we can get the nutritionist interested
in ferret medicine. Do you think he can get his grant extended to
include ferrets? LOL
"I'm not sure what you want to know about the proteins, but I'll tell you
what I think is important. There is no difference in the fundamental
structure of plant and animal proteins (they are just polymers of amino
acids) or in the way they are made. The major difference, at least as
far
as the human diet is concerned, is wheather or not the protein is
"complete". You probably remember that there are non-essential amino
acids
(those that we can make in our bodies from other sources) and essential
amino acids (those that we cannot make and therefore must get from the
diet
in order to avoid deficiency). For humans, the essential amino acids can
be remembered by the acronym PVT T HALL (phenylalanine, valine,
threonine,
tryptophan, histidine, arginine, lysine, leucine). There are no plants
that naturally make complete proteins (or at least complete enough for us
(except soybeans which come close)), so if you had a diet, for example
that
involved only legumes, you would be deficient in whatever amino acid
legumes are low in, lose a lot of muscle due to protein breakdown (in the
body's attempt to get that amino acid), and eventually die. That's why
vegetarians must carefully complement their proteins. For example,
whatever amino acid that is missing in legumes is plentiful in rice (and
vice versa). That's why beans and rice are usually eaten together. In
the
agricultural world, it is big business to genetically modify plants to
make
proteins that contain lots of the amino acid they normally lack. For
example, there are strains if high-lysine corn (since corn normally is
very
low in lysine). I think a lot of these plants are "controversial",
though,
because people are so scared of genetically modified foods. Another
thing
about essential amino acids is that different species of animals have
differences in what amino acids are essential to them. I once saw a
program on people who are vegetarians and insist that their pets be as
well. It's very easy to kill a pet that way. Since humans can make some
amino acids that their pets cannot, a vegetarian human diet may cause no
problem to themselves, but kill their pet."
I am also thinking there are more non-digestable parts of the plants -
Patty
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