SPECIAL REPOR T
Should you be eating more
Americans have had a love/hate relationship with protein, and the
protein pendulum has been swinging like crazy lately. Many of
us grew up thinking only good things about protein. Indeed, we
can ’t live without it. But the trouble may be too much of a good
thing. Indeed, some researchers have linked a high intake of
animal protein to heart disease and other chronic disorders. On
the other hand, high-protein weight-loss diets are the craze once
again, as they were in the late sixties and early seventies (see box
on page 5). If all this increasingly contradictory advice about
protein makes your head spin, here ’s the lowdown.
What ’s the problem with eating lots of protein?
A diet high in protein-especially animal protein-is associated
with an increased risk not only of heart disease and some cancers
(such as colon and prostate), but also of osteoporosis and kidney
However, it ’s hard to prove this link, since we seldom
eat pure protein.
People who eat lots of animal protein do have
higher rates of heart disease and cancers, but their diets also tend
to be high in fat and low in antioxidants and fiber, as well as other
potentially beneficial substances. Moreover, those who eat lots
of animal protein may also be less health-conscious in general
and less physically active than others. It may be such factors,
rather than protein intake itself, that account for most of the
Is protein from plants more healthful?
In carefully controlled studies, animals fed large amounts of
isolated animal protein develop higher levels of blood choles-
terol (especially LDL, the ‘bad” kind) than those fed vegetable
that something about the composition of
animal protein boosts cholesterol.
People who get their protein from plants have a lower risk of
heart disease and are healthier in general. Last year, for instance,
a widely publicized analysis of the benefits of soy protein
suggested that it helps lower blood cholesterol and is thus good
for the heart (though other compounds in soy may be largely
November 1995). Vegetarian
sources of protein are also preferable because they ’re usually low
in fat and high in fiber and other potentially beneficial sub-
stances. Nevertheless, a few studies have suggested that a very
high intake of even plant protein is undesirable, but it ’s rare for
vegetarians to consume such large amounts of protein.
Don ’t vegetarians have trouble getting enough protein?
Vegetarian diets generally supply more than enough protein.
Many grains, legumes, nuts, and seeds are good sources of
protein. However, except for soybeans, plant foods contain
protein that ’s incomplete-that is, it has low and sometimes
insufficient amounts of one or more of the nine essential amino
acids. (Amino acids are protein ’s building blocks; the essential
ones are those the body can ’t synthesize.) But if vegetarians eat