One of the largest obstacles to becoming vegetarian (or vegan)
is a fear of getting inadequate amounts of protein (and to a lessor
extent, calcium, iron and B-12). In general, we would do well
to have a greater fear of getting too much of a good thing. With
the possible exception of pregnant women and impoverished individuals,
western adults (and some children) tend to suffer from excess
nutrition--not malnutrition. For instance, most everyone in this
country consumes too much protein--even vegetarians
A vegetarian diet is characterized by removing certain foods.
Many of the foods that are absent from a vegetarian diet may have
significant nutritional value. It is important to incorporate
alternate nutritional sources when removing animal foods from
a diet. Protein, calcium, iron, and B12 requirements are concerns
for vegetarians. Legumes and grains are good sources for protein
and contain significantly less amounts of saturated fat, cholesterol,
and sodium than animal sources. Spinach, turnip greens, and kale
are good sources for calcium. Prunes, baked beans, and molasses
are good sources for iron. Another excellent source for iron is
fortified cereal, such as raisin bran. Most fortified cereals
also contain significant amounts of B12. picture mosaic program
Proteins, the 'building blocks of the body,' are made up of 22
amino acids. 14 of the amino acids are made by the body. The other
eight must be acquired through food. These are known as the essential
amino acids (EAAs) and all eight must be present in order for
the proper building to occur. Animal protein contains all of the
EAAs and is termed a complete protein. Different vegetable proteins
contain varied amounts of the EAAs and are thus referred to as
incomplete. Therefore vegetarians must eat a variety of protein
sources in order to get adequate amounts of each EAA.
|
|
Certain plant constituents appear to inhibit the absorption of
dietary calcium, but within the context of the total diet, this
effect does not appear to be significant. Calcium from low-oxalate
vegetable greens, such as kale, has been shown to be absorbed
as well or better than calcium from cow's milk. Calcium deficiency
in vegetarians is rare, and there is little evidence to show that
calcium intakes below the Recommended Dietary Allowance cause
major health problems in the vegetarian population. The relatively
high US recommendations for calcium intake, compared with those
for populations consuming a more plant based diet, are designed
to compensate for the calciuric effect of high intakes of animal
protein, which are customary in the United States. Studies have
shown that vegetarians, on the other hand, absorb and retain more
calcium from foods than do nonvegetarians. free ebook, the startling.
Vegetarians are not at greater risk of iron deficiency than nonvegetarians,
but Western vegetarians generally have better iron status than
those in developing countries. Western vegetarians generally have
an adequate intake of iron from plant products. They also consume
greater amounts of ascorbic acid, an important enhancer of nonheme
iron absorption
A dietary pattern that includes animal products such as milk
and milk products is unlikely to be deficient in vitamin B-12.
Vegans should include a reliable source (of vitamin B-12) in their
diets. Cyanocobalamin, the form of vitamin B-12 that is physiologically
active for human beings, is available from vitamin supplements
or fortified foods such as some commercial breakfast cereals,
soy beverages, some brands of nutritional yeast, and other products.
Lack of intrinsic factor in the stomach, rather than diet is the
most common cause of vitamin B-12 deficiency.
Plant sources of protein alone can provide adequate amounts of
the essential and nonessential amino acids, assuming that dietary
protein sources from plants are reasonably varied and that caloric
intake is sufficient to meet energy needs. Whole grains, legumes,
vegetables, seeds, and nuts all contain essential and nonessential
amino acids. Conscious combining of these foods within a given
meal, as the complementary protein dictum suggests, is unnecessary.
Additionally, soy protein has been shown to be nutritionally equivalent
in protein value to proteins of animal origin and, thus, can serve
as the sole source of protein intake if desired.
Although most vegetarian diets meet or exceed the Recommended
Dietary Allowances for protein, they often provide less protein
than nonvegetarian diets. This lower protein intake may be associated
with better calcium retention in vegetarians and improved kidney
function in individuals with prior kidney damage. Further, lower
protein intakes may result in a lower fat intake with its inherent
advantages, because foods high in protein are frequently high
in fat also. . . . Reduced consumption of meat and animal protein
has also been associated with decreased colon cancer in some,
but not all, studies of omnivores.
|
