you combine a steak with some bread or a potato — this is a signifi-
cant stress for the stomach, and indigestion often follows.
Amino Acids
Just as carbohydrates are made up of sugars, and fats are composed
of fatty acids, dietary protein is made up of building blocks called
amino acids. In order to obtain these vital components, the intestine
must do its job. First, protein must be efficiently digested in the intes-
tine, resulting in breakdown into amino acids. Second, these amino
acids must be absorbed into the body. Once absorbed, the amino acids
are used either as individual products, or recombined as proteins. For
example, the amino acid tryptophan is used to make certain neuro-
transmitters in the brain. Or, recombining many amino acids provides
for the manufacture of new muscle cells.
There are at least 20 amino acids necessary to human nutrition, all
of which are indispensable for optimal health and human perform-
ance. While some amino acids can be manufactured in the body by
other raw materials from food, others called “essential amino acids”
must be taken in through the diet. While amino acids that are made
in the body are sometimes referred to as “non-essential,” this is mis-
leading as all amino acids are essential.
In general, animal foods are the best sources of protein and con-
tain all the amino acids. Overall, the highest-rated protein food is
eggs, followed by beef and fish. With the exception of soybeans,
which are mostly carbohydrate, vegetable foods individually contain
only some of the amino acids. Combining the right non-animal foods
can provide a complete amino-acid meal. But eating all the amino
acids at one meal is not necessary.
For those who don’t eat animal products, obtaining all the amino
acids is accomplished by combining enough variety, since no one
plant-based food, except soybeans, contains all the amino acids
(although soy is very low in the amino acid methionine). Certain com-
binations of plant foods, such as beans and rice, or whole grains and
legumes, can provide a complete protein. However, combining meals
high in carbohydrates (such as rice, beans, grains, etc.) with protein
can reduce digestibility, with the result that some protein will not
THE POWER OF PROTEIN • 85