The Rewards of Eating Vegetarian
A plant-based diet has compelling
health benefits. At the same time, it can require planning to
get the optimal balance of
The American Dietetic Association (ADA) asserts that
vegetarian diets are healthful, nutritionally adequate, and
for the prevention and treatment of certain diseases. Studies
show that vegetarians have reduced risks of heart disease, high
blood pressure, type 2 diabetes, obesity, and some types of cancer.
How do vegetarian diets produce these health benefits? Generally
lower in total fat, saturated fat, and cholesterol, they help
decrease blood cholesterol levels. In addition, plant foods contain
compounds that interfere with the actions of carcinogens (cancer-causing
chemicals), help repair damaged cells, and alter levels of hormones
involved in cancer development. They also provide ample fiber,
which may lower the risk of heart disease, stroke, diabetes,
and gastrointestinal cancers.
Do Vegetarians Get Enough Protein?
Proteins are composed of amino
acids—substances that the
body needs for growth and for the maintenance of muscles, tendons,
ligaments, and other tissues. Although many amino acids are manufactured
in the body, nine “essential” amino acids can only
be obtained from food. A food protein that supplies all of the
essential amino acids is called a complete protein (animal foods
are sources of complete protein). A food protein that does not
supply all the essential amino acids is called an incomplete
Plant proteins (with the exception of soy protein) are
incomplete. But if the sources of dietary protein are varied,
alone can supply enough of the essential amino acids—especially
if the diet regularly includes high-protein plant foods such
as beans, lentils, nuts, nut butters, and whole-grain breads
and cereals. In addition, certain combinations—for example,
rice and beans, or corn and beans—form complete proteins.
And while it’s not necessary to eat these food combinations
at the same meal, they should be consumed over the course of
Soy foods contain especially high-quality protein. In
fact, soy protein (found in soybeans, edamame, tofu, tempeh,
and soy milk) contains enough of all the essential amino acids
to be considered a complete protein equal in quality to proteins
of animal origin.
Nutrient Needs for Strict Vegetarians
While a vegetarian diet
is healthful, strict vegetarians (vegans) may be deficient in
certain nutrients—such as vitamin B12,
vitamin D, calcium, iron, and zinc—that are found principally
in animal products. Careful food choices and use of a multivitamin
supplement can help prevent nutritional deficiencies caused by
strict vegetarian diets.
Vitamin B12. Found in such animal foods
as fish, dairy, eggs, meat, and poultry, vitamin B12 is required
to maintain healthy
nerve cells, to produce red blood cells, and to make DNA, the
genetic material in all cells. As we age, our ability to absorb
vitamin B12 diminishes. In fact, some experts estimate that 10%
to 30% of older adults do not absorb vitamin B12 efficiently
Because they eat no animal foods, strict vegetarians
are at risk for developing a deficiency of this important vitamin,
if they also eat few B12-fortified foods (such as fortified cereals).
For this reason, it is a good idea for vegetarians—particularly
those who are over the age of 50—to take a vitamin B12
Vitamin D. This vitamin is vital
for maintaining proper calcium balance, which is necessary for
bone and muscle health
functions. Mostly produced by the body through exposure to sunlight,
vitamin D is also found in some foods, principally fatty fish
and fish oils, as well as certain fortified foods, such as some
brands of soy milk, cereal, cow’s milk, and orange juice.
show that the diets of many vegetarians, particularly vegans,
contain inadequate amounts of vitamin D. And though lacto-ovo-vegetarians
probably get enough vitamin D, and vegans can get vitamin D
from fortified foods, it is still a good idea for them to consult
their physician or a registered dietitian about supplementation.
Calcium. This mineral is essential
for numerous functions, including regulation of the heartbeat,
conduction of nerve impulses, stimulation
of hormone secretions and blood clotting, as well as for building
and maintaining healthy bones. Because lacto-ovo-vegetarians
consume dairy foods, their calcium intakes are comparable to
or higher than those of nonvegetarians. However, the calcium
intakes of vegans are generally lower than those of either lacto-ovo-vegetarians
Good plant sources of calcium include bok choy,
broccoli, napa cabbage, collards, kale, okra, and turnip greens.
vegans may find it easier to meet their calcium needs by including
fortified foods in their diets. Foods fortified with calcium
include certain brands of orange juice and apple juice, breads,
cereals, soy milk, and tofu. If you are concerned about your
calcium intake, consult your physician about taking calcium supplements.
Iron. Adequate iron intake is necessary
to prevent anemia. Because the richest dietary sources of iron
are red meat and liver, vegetarians
have a greater risk of iron deficiency than nonvegetarians. Although
plant foods can contain iron, it’s a type of iron (“nonheme” iron)
that is not absorbed as well as the “heme” iron contained
in meat. In addition, the absorption of nonheme iron can be inhibited
by certain substances in plant foods such as fiber, phytates
(in cereal grains), and oxalates (in green leafy vegetables).
Nonheme iron can be absorbed better if a source of vitamin C
is eaten at the same time as the iron-containing food. Good nonmeat
sources of iron include dried beans, peas, whole-grain breads,
spinach, enriched products, nutritional yeast, and dried fruits.
Plants foods that are a good source of vitamin C include citrus
fruits and juices, strawberries, tomatoes, broccoli, bell peppers,
cooking greens, and potatoes.
Zinc. This essential mineral supports
a healthy immune system and is required for DNA synthesis. It
is also needed for wound
healing, as well as maintaining your sense of taste and smell.
Zinc is most abundant in animal foods, and although the mineral
is present in certain plant foods—such as whole grains,
wheat germ, fortified cereal, nuts, and legumes—its bioavailability
appears to be lower in vegetarian diets.
Vegetarians may need
as much as 50% more zinc than nonvegetarians because of the lower
absorption of zinc from plant foods; so
it’s very important for vegetarians to consume high-quality
sources of zinc on a regular basis. In addition, most multivitamins
contain enough zinc to help make up for any deficiencies in a
While all vegetarian
diets place plant-based foods on center stage, the extent
to which animal products are avoided can vary. For example:
• Vegans (pronounced VEE-gans), also called strict, pure, or total vegetarians,
eat only plant foods; they avoid all products derived from animals (including
• Ovo-vegetarians allows eggs in addition to plant foods.
• Lacto-ovo-vegetarians allow dairy and eggs in addition to plant foods.
• Pesco-vegetarians don’t eat red meat, but do eat fish, eggs, and
• Semi-vegetarians don’t eat red meat, but do include poultry, fish,
eggs, and dairy.