I recently found this:

http://www.vegansociety.com/html/foo...on/protein.php

Protein Combining - Is It Necessary?

No, it really isn't necessary! Research on laboratory rats also led to
the misleading theory of protein combining. [2] Protein combining has
unfortunately gained momentum over the years. It was based on the idea
that complementary protein foods with different limiting amino acids,
such as beans and grains, should be eaten at each meal in order to
enhance the availability of amino acids.

Proteins in foods have a distinctive pattern, being higher in some
amino acids and lower in others. For many years the quality of a
protein reflected its amino acid pattern and was measured against the
protein in a hen's egg which counted as 100%. By this method, in each
protein the amino acid furthest below the standard reference is known
as the limiting amino acid. This is not necessarily the one present in
the lowest absolute amount but the one present in the lowest
proportion compared to protein in a hen's egg! In most grains and
seeds, the limiting amino acid is lysine, while in most pulses it is
methionine. Tryptophan is the limiting amino acid in corn (maize), and
in beef it is methionine. Although each food has a limiting amino
acid, most foods have all amino acids in adequate amounts for human
health.

Even vegetarians are sometimes advised to combine vegetable proteins
with dairy foods. This advice is now very old fashioned. Protein
combining may reduce the amount of protein required to keep the body
in positive protein balance but several human studies have indicated
that this is neither necessary nor even always the case. Diets based
solely on plant foods easily supply the recommended amounts of all the
indispensable amino acids, and protein combining at each meal is
unnecessary. Soya protein is actually equivalent in biological value
to animal protein.

and aslo:

http://www.vrg.org/nutrition/protein.htm

What about combining or complementing protein? Doesn't that make the
protein issue much more complex? Let's look at a little background on
the myth of complementing proteins. Protein is made up of amino acids,
often described as its building blocks. We actually have a biological
requirement for amino acids, not for protein. Humans cannot make nine
of the twenty common amino acids, so these amino acids are considered
to be essential. In other words, we must get these amino acids from
our diets. We need all nine of these amino acids for our body to make
protein.

Eggs, cow's milk, meat, and fish have been designated as high quality
protein (1). This means that they have large amounts of all the
essential amino acids. Soybeans, quinoa (a grain), and spinach also
are considered high quality protein. Other protein sources of
non-animal origin usually have all of the essential amino acids, but
the amounts of one or two of these amino acids may be low. For
example, grains are lower in lysine (an essential amino acid) and
legumes are lower in methionine (another essential amino acid) than
those protein sources designated as high quality protein.

Frances Moore Lappe, in her book Diet for a Small Planet (7) advocated
the combining of a food low in one amino acid with another food
containing large amounts of that amino acid. This got to be a very
complicated process, with each meal having specific amounts of certain
foods in order to be certain of getting a favorable amino acid mix.
Many people got discouraged with the complexity of this approach.
Actually, Lappe was being overly conservative to avoid criticism from
the "Nutrition Establishment." She has since repudiated strict protein
combining, saying "In combating the myth that meat is the only way to
get high quality protein, I reinforced another myth. I gave the
impression that in order to get enough protein without meat,
considerable care was needed in choosing foods. Actually it is much
easier than I thought" (8).

We recommend eating a variety of unrefined grains, legumes, seeds,
nuts, and vegetables throughout the day, so that if one food is low in
a particular essential amino acid, another food will make up this
deficit (9,10).

Even if you ate only one food and not the variety of foods typical of
a vegan diet, you would probably get enough protein and essential
amino acids (11). Remember, almost all protein sources of non-animal
origin contain all of the essential amino acids. You would have to eat
a lot of the protein source (if there was only one source of protein
in your diet) to meet essential amino acid needs. Table 4 (page 147)
shows the amounts of various foods an adult male would have to eat if
he relied on a single food source for his protein needs. Females would
need about 20 percent less of each food due to the lower protein
recommendation for women.

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Is it true???

tracy