Lehigh Valley Vegetarians

ADA REPORTS

Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets

It is the position of the American Dietetic Association and
Dietitians of Canada that appropriately planned vegetarian diets
are healthful, nutritionally adequate, and provide health benefits
in the prevention and treatment of certain diseases. Approximately
2.5% of adults in the United States and 4% of adults in
Canada follow vegetarian diets. A vegetarian diet is defined as
one that does not include meat, fish, or fowl. Interest in vegetarianism
appears to be increasing, with many restaurants
and college food services offering vegetarian meals routinely.
Substantial growth in sales of foods attractive to vegetarians
has occurred, and these foods appear in many supermarkets.
This position paper reviews the current scientific data related
to key nutrients for vegetarians, including protein, iron, zinc,
calcium, vitamin D, riboflavin, vitamin B-12, vitamin A, n-3
fatty acids, and iodine. A vegetarian, including vegan, diet can
meet current recommendations for all of these nutrients. In
some cases, use of fortified foods or supplements can be helpful
in meeting recommendations for individual nutrients.
Well-planned vegan and other types of vegetarian diets are
appropriate for all stages of the life cycle, including during
pregnancy, lactation, infancy, childhood, and adolescence.
Vegetarian diets offer a number of nutritional benefits, including
lower levels of saturated fat, cholesterol, and animal
protein as well as higher levels of carbohydrates, fiber, magnesium,
potassium, folate, and antioxidants such as vitamins
C and E and phytochemicals. Vegetarians have been reported
to have lower body mass indices than nonvegetarians, as well
as lower rates of death from ischemic heart disease; vegetarians
also show lower blood cholesterol levels; lower blood
pressure; and lower rates of hypertension, type 2 diabetes,
and prostate and colon cancer. Although a number of federally
funded and institutional feeding programs can accommodate
vegetarians, few have foods suitable for vegans at this time.
Because of the variability of dietary practices among vegetarians,
individual assessment of dietary intakes of vegetarians is
required. Dietetics professionals have a responsibility to support
and encourage those who express an interest in consuming a
vegetarian diet. They can play key roles in educating vegetarian
clients about food sources of specific nutrients, food purchase
and preparation, and any dietary modifications that may be necessary
to meet individual needs. Menu planning for vegetarians
can be simplified by use of a food guide that specifies food
groups and serving sizes. J Am Diet Assoc. 2003;103:748-765.

POSITION STATEMENT

VEGETARIANISM IN PERSPECTIVE

A vegetarian is a person who does not eat meat, fish, or fowl or
products containing these foods. The eating patterns of vegetarians
may vary considerably. The lacto-ovo-vegetarian eating
pattern is based on grains, vegetables, fruits, legumes, seeds,
nuts, dairy products, and eggs but excludes meat, fish, and
fowl. The lacto-vegetarian excludes eggs as well as meat, fish,
and fowl. The vegan, or total vegetarian, eating pattern is similar
to the lacto-vegetarian pattern, with the additional exclusion
of dairy and other animal products. Even within these
patterns, considerable variation may exist in the extent to
which animal products are avoided.

People choosing macrobiotic diets are frequently identified
as following a vegetarian diet. The macrobiotic diet is based
largely on grains, legumes, and vegetables. Fruits, nuts, and
seeds are used to a lesser extent. Some people following a
macrobiotic diet are not truly vegetarian because they use limited
amounts of fish. Some "self-described" vegetarians, who
are not vegetarians at all, will eat fish, chicken, or even meat
(1,2). Some research studies have identified these "self-described"
vegetarians as semivegetarians and have defined semi-
vegetarian as occasional meat eaters who predominately practice
a vegetarian diet (3) or those who eat fish and poultry but
less than 1 time per week (4). Individual assessment is required
to accurately evaluate the nutritional quality of the diet of a
vegetarian or someone who says that they are vegetarian.

Common reasons for choosing a vegetarian diet include health
considerations, concern for the environment, and animal welfare
factors (5,6). Vegetarians also cite economic reasons, ethical considerations,
world hunger issues, and religious beliefs as their reasons
for following their chosen eating pattern.

Consumer Trends

In 2000, approximately 2.5% of the US adult population (4.8
million people) consistently followed a vegetarian diet and affirmed
that they never ate meat, fish, or poultry (7). Slightly
less than 1% of those polled were vegans (7). According to this
poll, vegetarians are most likely to live on the east or west coast,
in large cities, and to be female. Approximately 2% of 6-to

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17-year-old children and adolescents in the United States are
vegetarians, and around 0.5% of this age group are vegan (8).
According to a 2002 survey (9), about 4% of Canadian adults
are vegetarian; this represents an estimated 900,000 people.
Factors that may affect the number of vegetarians in the United
States and Canada in the future include an increased interest in
vegetarianism and the arrival of immigrants from countries
where vegetarianism is commonly practiced (10). Twenty to
25% of adults in the United States report that they eat 4 or
more meatless meals weekly or usually or sometimes maintain
a vegetarian diet, suggesting an interest in vegetarianism (11).
Additional evidence for the increased interest in vegetarianism
includes the emergence of animal rights/ethics courses on college
and university campuses; the proliferation of Web sites,
magazines and newsletters, and cookbooks with a vegetarian
theme; and the publics attitude toward ordering a vegetarian
meal when eating away from home. More than 5% of those
surveyed in 1999 said they always order a vegetarian meal
when they eat out; close to 60% sometimes, often, or always
order a vegetarian item at a restaurant (12).

Restaurants have responded to this interest in vegetarianism.
The National Restaurant Association reports that 8 out of
10 restaurants in the United States with table service offer
vegetarian entrees (13). Fast-food restaurants are beginning to
offer salads, veggie burgers, and other vegetarian options.
Many college students consider themselves vegetarians. In response
to this, most university food services offer vegetarian
options (14).

There has also been a growth in professional interest in vegetarian
nutrition; the number of articles in the scientific literature
related to vegetarianism has increased from less than 10
articles per year in the late 1960s to 76 articles per year in the
1990s (15). In addition, the main focus of the articles is changing.
Twenty-five or more years ago, articles primarily had
themes questioning the nutritional adequacy of vegetarian diets.
More recently, the theme has been the use of vegetarian
diets in the prevention and treatment of disease. More articles
feature epidemiological studies, and fewer reports are case
studies and letters to the editor (15).

There is a growing appreciation for the benefits of plant-
based diets, defined as diets that include generous amounts of
plant foods and limited amounts of animal foods. The American
Institute for Cancer Research and the World Cancer Research
Fund call for choosing predominantly plant-based diets rich in
a variety of vegetables and fruits, legumes, and minimally processed
starchy staple foods and limiting red meat consumption,
if red meat is eaten at all (16). The American Cancer Society
recommends choosing most food from plant sources (17). The
American Heart Association recommends choosing a balanced
diet with an emphasis on vegetables, grains, and fruits (18),
and the Heart and Stroke Foundation of Canada recommends
using grains and vegetables instead of meat as the centerpiece
of meals (19). The Unified Dietary Guidelines developed by the
American Cancer Society, the American Heart Association, the
National Institutes of Health, and the American Academy of
Pediatrics call for a diet based on a variety of plant foods, including
grain products, vegetables, and fruits to reduce risk of
major chronic diseases (20).

New Product Availability

The US market for vegetarian foods (foods like meat analogs, nondairy
milks, and vegetarian entrees that directly replace meat or
other animal products) was estimated to be $1.5 billion in 2002, up

from $310 million in 1996 (21). This market is expected to nearly
double by 2006 to $2.8 billion (21). Canadian sales of meat analogs
more than tripled between 1997 and 2001 (22).

The ready availability of new products, including fortified
foods and convenience foods would be expected to have a
marked impact on nutrient intake of vegetarians. Fortified
foods such as soymilks, meat analogs, juices, and breakfast
cereals can add substantially to vegetarians intakes of calcium,
iron, zinc, vitamin B-12, vitamin D, and riboflavin. Vegetarian
convenience foods including veggie burgers and veggie dogs,
frozen entrees, meals in a cup, and soymilk can make it much
simpler to be a vegetarian today than in the past.

Vegetarian foods are readily available, both in supermarkets
and in natural foods stores. About half of vegetarian foods volume
is sold through supermarkets and about half through natural
foods stores (21). Three-fourths of soymilk sales take
place in supermarkets (21).

Public Policy Statements and Vegetarian Diets

The United States Dietary Guidelines (23) state, Vegetarian
diets can be consistent with the Dietary Guidelines for Americans,
and meet Recommended Dietary Allowances for nutrients.
They give recommendations on meeting nutrient requirements
for those who choose to avoid all or most animal
products. Some have said that implementation of the Dietary
Guidelines can best be achieved by use of vegetarian and plant-
rich diets (24). National food guides include some vegetarian
options. Foods commonly eaten by vegetarians such as legumes,
tofu, soyburgers, and soymilk with added calcium are
included in a table accompanying the USDA's Food Guide Pyramid
(23). Canadians Food Guide to Healthy Eating can be used
by lacto and lacto-ovo-vegetarians (25). Health Canada has
stated that well-planned vegetarian diets are supportive of
good nutritional status and health (26).

HEALTH IMPLICATIONS OF VEGETARIANISM

Vegetarian diets offer a number of advantages, including lower
levels of saturated fat, cholesterol, and animal protein and
higher levels of carbohydrates, fiber, magnesium, boron, folate,
antioxidants such as vitamins C and E, carotenoids, and phytochemicals
(27-30). Some vegans may have intakes for vitamin
B-12, vitamin D, calcium, zinc, and occasionally riboflavin that
are lower than recommended (27,29,31).

NUTRITION CONSIDERATIONS FOR VEGETARIANS

Protein

Plant protein can meet requirements when a variety of plant foods
is consumed and energy needs are met. Research indicates that an
assortment of plant foods eaten over the course of a day can provide
all essential amino acids and ensure adequate nitrogen retention
and use in healthy adults, thus complementary proteins do
not need to be consumed at the same meal (32).

Estimates of protein requirements of vegans vary, depending to
some degree on diet choices (33). A recent meta analysis of nitrogen
balance studies found no significant difference in protein
needs due to the source of dietary protein (34,35). Based primarily
on the lower digestibility of plant proteins, other groups have
suggested that protein requirements of vegans may be increased
by 30% to 35% for infants up to the age of 2 years, 20% to 30% for
2-to 6-year-old children, and 15% to 20% for those 6 years and
older, in comparison with those of nonvegetarians (36).

The quality of plant proteins varies. Based on the protein

Journal of THE AMERICAN DIETETIC ASSOCIATION / 749

ADA REPORTS

digestibility corrected amino acid score (PDCAAS), which is
the standard method for determining protein quality, isolated
soy protein can meet protein needs as effectively as animal
protein, whereas wheat protein eaten alone, for example, may
be 50% less usable than animal protein (37). Nutrition care
professionals should be aware that protein needs might be
higher than the RDA in vegetarians whose dietary protein
sources are mainly those that are less well digested, such as
some cereals and legumes.

Cereals tend to be low in lysine, an essential amino acid. This
may be relevant when evaluating diets of individuals who do
not consume animal protein sources and are relatively low in
protein (35). Dietary adjustments such as the use of more
beans and soy products in place of other protein sources that
are lower in lysine or an increase in dietary protein from all
sources can ensure an adequate intake of lysine.

Although some vegan women have protein intakes that are marginal,
typical protein intakes of lacto-ovo-vegetarians and of vegans
appear to meet and exceed requirements (29). Athletes can
also meet their protein needs on plant-based diets (38,39).

Iron

Plant foods contain only nonheme iron, which is more sensitive
than heme iron to both inhibitors and enhancers of iron absorption.
Inhibitors of iron absorption include phytate; calcium;
teas, including some herb teas; coffee; cocoa; some spices; and
fiber (40). Vitamin C and other organic acids found in fruits and
vegetables can enhance iron absorption and can help to reduce
effects of phytate (41-43). Studies show that iron absorption
would be significantly reduced if a diet were to be high in inhibitors
and low in enhancers. Recommended iron intakes for
vegetarians are 1.8 times those of nonvegetarians because of
lower bioavailability of iron from a vegetarian diet (44).

The main inhibitor of iron absorption in vegetarian diets is
phytate. Because iron intake increases as phytate intake increases,
effects on iron status are somewhat less than might be
expected. Fiber appears to have a minor effect on iron absorption
(45,46). Vitamin C, consumed at the same time as the iron
source, can help to reduce the inhibitory effects of phytate
(42,43), and some research links high vitamin C intake to improved
iron status (47,48). The same is true for organic acids in
fruits and vegetables (41). The higher intakes of vitamin C and
of vegetables and fruits by vegetarians can favorably impact
iron absorption (2). Some food preparation techniques such as
soaking and sprouting beans, grains, and seeds can hydrolyze
phytate (49-51) and may improve iron absorption (42,51,52).
Leavening of breads hydrolyzes phytate and enhances iron absorption
(49-51,53,54). Other fermentation processes, such as
those used to make soy foods like miso and tempeh, may also
make iron more available (55), although not all research supports
this. Whereas many studies of iron absorption have been
short term, there is evidence that adaptation to low intakes
takes place over the longer term and involves both increased
absorption and decreased losses (56,57). It is likely that iron
needs will depend on the make up of the overall diet and be
significantly lower for some vegetarians than for others.

Studies typically show iron intake by vegans to be higher
than that of lacto-ovo-vegetarians and of nonvegetarians, and
most studies show iron intake by lacto-ovo-vegetarians to be
higher than that of nonvegetarians (29). Iron sources are
shown in the Table. Incidence of iron deficiency anemia among
vegetarians is similar to that of nonvegetarians (29,31,58). Although
vegetarian adults have lower iron stores than nonvegetarians, their
serum ferritin levels are usually within the normal range (58-62).

Zinc

Because phytate binds zinc, and animal protein is believed to
enhance zinc absorption, total zinc bioavailability appears to be
lower on vegetarian diets (63). Also, some vegetarians have
diets that are significantly below recommended intakes for zinc
(27,29,64,65). Although overt zinc deficiency has not been
seen in Western vegetarians, the effects of marginal intakes are
poorly understood (66). Zinc requirements for vegetarians
whose diets are high in phytate may exceed the RDA (44). Zinc
sources are shown in the Table.

Compensatory mechanisms may help vegetarians adapt to
lower intakes of zinc (65,67). Some food preparation techniques,
such as soaking and sprouting beans, grains, and seeds
as well as leavening bread, can reduce binding of zinc by
phytate and increase zinc bioavailability (49,50,68).

Calcium

Calcium is present in many plant foods and fortified foods (see
Table). Low-oxalate greens (bok choy, broccoli, Chinese/Napa
cabbage, collards, kale, okra, turnip greens) provide calcium
with high bioavailability (49% to 61%), in comparison with calcium-
set tofu, fortified fruit juices, and cows milk (bioavailability
in the range of 31% to 32%) and with fortified soymilk,
sesame seeds, almonds, and red and white beans (bioavailability
of 21% to 24%) (69-71). Figs and soy foods such as cooked
soybeans, soy nuts, and tempeh provide additional calcium.
Calcium-fortified foods include fruit juices, tomato juice, and
breakfast cereals. Thus, various food groups contribute dietary
calcium (72,73). Oxalates present in some foods can greatly
reduce calcium absorption, so vegetables that are very high in
these compounds, such as spinach, beet greens, and Swiss
chard, are not good sources of usable calcium despite their high
calcium content. Phytate may also inhibit calcium absorption.
However, some foods with high contents of both phytate and
oxalate, such as soy foods, still provide well-absorbed calcium
(71). Factors that enhance calcium absorption include adequate
vitamin D and protein.

Calcium intakes of lacto-vegetarians are comparable with or
higher than those of nonvegetarians (74,75), whereas intakes
of vegans tend to be lower than both groups and often below
recommended intakes (27,31,71,75). Diets high in sulfur-containing
amino acids may increase losses of calcium from bone.
Foods with a relatively high ratio of sulfur-containing amino
acids to protein include eggs, meat, fish, poultry, dairy products,
nuts, and many grains. There is some evidence that the
impact of sulfur-containing amino acids is only important with
low calcium intakes. Excessive sodium intake may also promote
calcium losses. In addition, some studies show that the
ratio of dietary calcium to protein is more predictive of bone
health than calcium intake alone. Typically, this ratio is high in
lacto-ovo-vegetarian diets and favors bone health, whereas
vegans have a calcium to protein ratio that is similar to or lower
than that of nonvegetarians (71,76).

All vegetarians should meet the recommended intakes for
calcium, established for their age group by the Institute of Medicine
(77). This can be accomplished, in nonpregnant, nonlactating
adults, by consuming at least 8 servings per day of foods
that provide 10% to 15% of the Adequate Intake (AI) for calcium,
as indicated in the Vegetarian Food Guide Pyramid and
Vegetarian Food Guide Rainbow (72,73). Adjustments for

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Table
Vegetarian food sources of nutrients
Nutrient Amount per serving
Iron 4ôôôôôômg ôôôôôô3
Soyfoods
Soybeans, cooked, 1/2 c (125 mL) 4.4
Soybeans, dry roasted, (soy nuts), 1/4 c (60 mL) 1.7
Soymilk 1/2 c (125 mL) 0.4-1.0
Tempeh, 1/2 c (83 g) 2.2
Tofu, firm, 1/2 c (126 g) 6.6
Veggie meats, fortified, 1 oz (28 g) 0.5-1.9
Legumes (cooked, 1/2 c/125 mL)
Adzuki beans 2.3
Baked beans, canned, vegetarian 1.7
Black beans 1.8
Chickpeas, garbanzo beans 2.4
Great northern beans 1.9
Kidney beans 2.6
Lentils 3.3
Lima beans 2.2
Navy beans 2.3
Pinto beans 2.2
Nuts, peanuts, seeds, and their butters
Almonds, 1/4 c (60 mL) 1.5
Cashews, 1/4 c (60 mL) 2.1
Peanut butter, 2 tbsp (30 mL) 0.6
Peanuts, dry roast, 1/4 c (60 mL) 0.8
Pumpkin and squash seeds, dried, 1/4 c (60 mL) 5.2
Sesame tahini, 2 tbsp (30 mL) 2.7
Sunflower seeds, toasted, 1/4 c (60 mL) 2.3
Breads, cereals, and grains
Barley, pearled, cooked, 1/2 c (125 mL) 1.0
Cereal, ready-to-eat, fortified, 1 oz (28 g) 2.1-18
Cream of Wheat, cooked, 1/2 c (125 mL) 5.1
Oatmeal, instant, fortified, cooked, 1/2 c (125 mL) 4.2
Oatmeal, regular, quick or instant, cooked, 1/2 c (125 mL) 1.6
Quinoa, cooked, 1/2 c (125 mL) 2.1
Wheat germ, 2 tbsp (14 g) 0.9
Whole wheat or white enriched bread, 1 slice (28 g) 0.9
Fruits (dried, 1/4 c/60 mL)
Apricots 1.5
Currants 1.2
Figs 1.1
Prunes 1.1
Raisins 1.1
Vegetables (cooked, 1/2 c/125 mL unless indicated otherwise)
Bok choy (Chinese cabbage, pak choi) 0.9
Broccoli 0.7
Green or yellow beans 0.8
Kale 0.6
Mung bean sprouts 0.8
Mushrooms 1.4
Potato, baked, with skin, 1 medium (173 g) 2.3
Tomato juice 0.7
Turnip greens 0.6
Other foods
Blackstrap molasses, 1 tbsp (15 mL) 3.5
Zinc
Soyfoods
Soybeans, cooked, 1/2 c (125 mL) 1.0
Soybeans, dry roasted, 1/2 c (60 mL) 2.1
Soymilk, 1/2 c (125 mL) 0.3
Soymilk, fortified, 1/2 c (125 mL) 0.5-1.0
Tempeh, 1/2 c (83 g) 0.9
Tofu, firm, 1/2 c (126 g) 1.0
Veggie ìmeats,î fortified, 1 oz (28 g) 1.2-2.3

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Table contíd
Vegetarian food sources of nutrients
Nutrient Amount per serving
Legumes (cooked, 1/2 c/125 mL) 4ôôôôôômg ôôôôôô3
Adzuki beans 2.0
Baked beans, canned, vegetarian 1.8
Black beans 1.0
Chickpeas, garbanzo beans 1.3
Great northern beans 0.8
Kidney beans 0.9
Lima beans 0.9
Lentils 1.2
Navy beans 2.3
Nuts, peanuts, seeds, and their butters
Almonds, 1/4 c (60 mL) 1.2
Cashews, 1/4 c (60 mL) 1.9
Peanut butter, 2 tbsp (30 mL) 0.9
Peanuts, dry roast, 1/4 c (60 mL) 1.2
Pumpkin and squash seeds, dried, 1/4 c (60 mL) 2.6
Sesame tahini, 2 tbsp (30 mL) 1.4
Sunflower seeds, toasted, 1/4 c (60 mL) 1.8
Breads, cereals, and grains
Barley, pearled, cooked, 1/2 c (125 mL) 0.6
Cereal, ready-to-eat, fortified, 1 oz (28 g) 0.7-15
Quinoa, cooked, 1/2 c (125 mL) 0.8
Wheat germ, 2 tbsp (14 g) 1.8
Whole wheat bread, 1 slice (28 g) 0.5
Vegetables (cooked, 1/2 cup/125 mL)
Mushrooms 0.7
Peas 1.0
Dairy foods and eggs
Cowís milk, 1/2 c (125 mL) 0.5
Cheddar cheese, 3/4 oz (21 g) 0.7
Egg, large, 1 (50 g) 0.5
Yogurt, 1/2 c (125 mL) 0.8-1.1
Calcium
Soyfoods
Cultured soy yogurt, fortified, 1/2 c (125 mL) 367
Soybeans, cooked, 1/2 c (125 mL) 88
Soybeans, dry roasted, (soy nuts), 1/4 c (60 mL) 60
Soybeans, green, 1/2 c (125 mL) 130
Soymilk, fortified, 1/2 c (125 mL) 100-159
Tofu, firm, calcium-set, 1/2 c (126 g) 120-430
Tempeh, 1/2 c (83 g) 92
Legumes (cooked, 1/2 c/125 mL)
Black beans 46
Chickpeas, garbanzo beans 40
Great northern or navy beans 60-64
Pinto beans 41
Vegetarian baked beans 64
Nuts, seeds and their butters
Almonds, 1/4 c (60 mL) 88
Almond butter, 2 tbsp (30 mL) 86
Sesame tahini, 2 tbsp (30 mL) 128
Breads, cereals, and grains
Cereal, ready-to-eat, fortified, 1 oz (28 g) 55-315
Fruits
Figs, dried, 5 137
Orange, 1 large 74
Orange juice, fortified, 1/2 c (125 mL) 150
Vegetables (cooked, 1 c/250 mL)
Bok choy (Chinese cabbage, pak choi) 167-188
Broccoli 79
Collard greens 239
Kale 99
Kale, Scotch 181
Mustard greens 109
Okra 107
Turnip greens 208

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Table contíd

Vegetarian food sources of nutrients

Nutrient Amount per serving

Other foods 4ôôôôôômg ôôôôôô3

Blackstrap molasses, 1 tbsp (15 mL) 172

Dairy products

Cowís milk, 1/2 c (125 mL) 137-158
Cheddar cheese, 3/4 oz (21 g) 153
Yogurt, plain, 1/2 c (125 mL) 137-230

Vitamin D 4ôôôôôômcg ôôôôôô3

Cereals, ready-to-eat, fortified, 1 oz (28 g) 0.5-1
Egg yolk, large, 1 (17 g) 0.6
Cowís milk, fortified, 1/2 c (125 mL) 1.2-1.3
Soymilk or other nondairy milk, fortified, 1/2 c (125 mL) 0.5-1.5

Riboflavin 4ôôôôôômg ôôôôôô3

Almonds, 1/4 c (60 mL) 0.3
Cereal, ready-to-eat, fortified, 1 oz (28 g) 0.2-1.7
Cowís milk, whole, 2% or skim, 1/2 c (125 mL) 0.2
Yogurt, 1/2 c (125 mL) 0.3
Egg, large, 1 (50 g) 0.6
Mushrooms, cooked, 1/2 c (125 mL) 0.2
Nutritional yeast miniflakes, 1 tbsp (3 g) 1.9
Soymilk, fortified, 1/2 c (125 mL) 0.2

Vitamin B-12 4ôôôôôômcg ôôôôôô3

Cereals, ready-to-eat, fortified, 1 oz (28 g) 0.6-6.0
Cowís milk, 1/2 c (125 mL) 0.4-0.5
Egg, large, 1 (50 g) 0.5
Nutritional yeast (Red Star Vegetarian Support Formula), miniflakes, 1 tbsp (3 g) 1.5
Soymilk or other nondairy milks, fortified, 1/2 c (125 mL) 0.4-1.6
Veggie ìmeats,î fortified, 1 oz (28 g) 0.5-1.2

Linolenic acid 4ôôôôôôôg ôôôôôôô3

Canola oil, 1 tbsp (15 mL) 1.3-1.6
Flaxseed, ground, 1 tbsp (15 mL) 1.9-2.2
Flaxseed oil, 1 tsp (5 mL) 2.7
Soybean oil, 1 tbsp (15 mL) 0.9
Soybeans, cooked, 1/2 c (125 mL) 1.0
Tofu, 1/2 c (126 g) 0.7
Walnuts, 1/4 c (60 mL) 2.7
Walnut oil, 1 tbsp (15 mL) 1.4-1.7

NOTE. Sources: Package information and data from US Department of Agriculture, Agricultural Research Service, 2002; USDA Nutrient Database for Standard
Reference, Release 15; Nutrient Data Laboratory Home Page, http://www.nal.usda.gov/fnic/foodcomp; Bhatty RS. Nutrient composition of whole flaxseed and
flaxseed meal. In: Cunnane SC, Thompson LU, eds. Flaxseed and Human Nutrition. Champaign, IL: AOCS Press; 1995:22-42.

other stages of the life cycle are available (72,73). Many vegans
may find that it is easier to meet needs if fortified foods or
supplements are included (69-71,78).

Vitamin D

Vitamin D status depends on sunlight exposure and intake of
vitamin D fortified foods or supplements. Sun exposure to the
face, hands, and forearms for 5 to 15 minutes per day during the
summer at the 42nd latitude (Boston) is believed to provide
sufficient amounts of vitamin D for light-skinned people (79).
Those with dark skin require longer exposure (79). Sun exposure
may be inadequate for those living in Canada and at northern
latitudes in the United States, especially in winter months,
for those in smoggy regions, and for those whose sun exposure
is limited. Furthermore, infants, children, and older adults synthesize
vitamin D less efficiently (77,79,80). Sunscreen can
interfere with vitamin D synthesis, although reports are inconsistent
and may depend on amount of sunscreen applied
(79,81,82). Low vitamin D levels and reduced bone mass have
been observed in some vegan populations at northern latitudes
who did not use supplements or fortified foods, particularly

children following macrobiotic diets and adult Asian vegetarians
(29,83-85).

Foods that are fortified with vitamin D include cowís milk,
some brands of soymilk and rice milk, and some breakfast cereals
and margarines (see Table). Vitamin D3 (cholecalciferol)
is of animal origin, whereas vitamin D2 (ergocalciferol) is a
form acceptable to vegans. Vitamin D2 may be less bioavailable
than vitamin D3, which could raise the requirements of vegetarians
who depend on D2 supplements to meet vitamin D
needs (86). If sun exposure and intake of fortified foods are
insufficient, vitamin D supplements are recommended.

Riboflavin

Some studies have shown vegans to have lower intakes of riboflavin,
compared with nonvegetarians; however, clinical riboflavin
deficiency has not been observed (27,29,31). In addition to
foods shown in the Table, foods that provide about 1 mg of
riboflavin per serving are asparagus, bananas, beans, broccoli,
figs, kale, lentils, peas, seeds, sesame tahini, sweet potatoes,
tofu, tempeh, wheat germ, and enriched bread (87).

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Vitamin B-12

Sources of vitamin B-12 that are not derived from animals include
B-12 fortified foods (such as some brands of soymilk,
breakfast cereals, and nutritional yeast) or supplements (see
Table). Unless fortified, no plant food contains significant
amounts of active vitamin B-12. Foods such as sea vegetables
and spirulina may contain vitamin B-12 analogs; neither these
nor fermented soy products can be counted on as reliable
sources of active vitamin B-12 (29,88). Lacto-ovo-vegetarians
can get adequate vitamin B-12 from dairy foods and eggs if
these foods are consumed regularly.

Vegetarian diets are typically high in folic acid, which can
mask the hematological symptoms of vitamin B-12 deficiency.
Therefore, some cases of deficiency may not be detected until
after the onset of neurological symptoms (89). If there are
concerns about vitamin B-12 status, serum homocysteine,
methylmalonic acid, and holotranscobalamin II should be measured
(90).

A regular source of vitamin B-12 is crucial for pregnant and
lactating women and for breastfed infants if the motherís diet is
not supplemented. Infants born to vegan mothers whose diets
lack reliable sources of this vitamin are at especially high risk of
deficiency. Maternal vitamin B-12 intake and absorption during
pregnancy appear to have a more important influence on vitamin
B-12 status of the infant than do maternal vitamin B-12
stores (91). Because 10% to 30% of those over the age of 50
years, regardless of the type of diet they follow, lose their ability
to digest the protein-bound form of the vitamin that is
present in eggs, dairy, and other animal products, all people
over the age of 50 should use vitamin B-12 supplements or
fortified foods (92).

Studies indicate that some vegans and other vegetarians do
not regularly consume reliable sources of vitamin B-12 and that
this is reflected in less than adequate vitamin B-12 status
(27,29,88,89,93-95). It is essential that all vegetarians use a
supplement, fortified food, dairy products, or eggs to meet recommended
intakes of vitamin B-12 (see Table).

Absorption is most efficient when small amounts of vitamin
B-12 are consumed at frequent intervals. This could be
achieved through use of fortified foods. When less than 5 gof
crystalline vitamin B-12 is consumed at one time, approximately
60% is absorbed, whereas 1% of a dose of 500 gor
higher of vitamin B-12 is absorbed (92).

Vitamin A/Beta Carotene

Because preformed vitamin A is found only in animal foods,
vegans get all of their vitamin A from conversion of dietary
carotenoids, particularly beta carotene. Research suggests that
absorption of beta carotene from plant foods is less efficient
than previously believed (44,96). This suggests that vegans
intake of vitamin A is about half of what previous studies have
suggested, and intake by lacto-ovo-vegetarians may be 25%
lower than previously shown. Despite this, vegetarians have
been reported to have higher serum carotenoid levels than
nonvegetarians (29). Vitamin A requirements can be met with
the inclusion of three servings per day of deeply yellow or
orange vegetables, leafy green vegetables, or fruits that are rich
in beta carotene (apricots, cantaloupe, mango, pumpkin).
Cooking increases beta carotene absorption, as does the addition
of small amounts of fat to meals (97). Chopping and pureeing
vegetables may also increase bioavailability (98,99).

N-3 Fatty Acids

Whereas vegetarian diets are generally rich in n-6 fatty acids
(especifically linoleic acid), these diets can be low in n-3 fatty
acids, resulting in an imbalance that can inhibit production of
the physiologically active long chain n-3 fatty acids, eicosapentaenoic
acid (EPA), and docosahexaenoic acid (DHA). Diets
that do not include fish, eggs, or generous amounts of sea vegetables
generally lack direct sources of EPA and DHA. Recently,
vegan sources of DHA derived from microalgae have
become available as supplements in nongelatin capsules. Algae
sources of DHA have been shown to positively affect blood
levels of DHA and of EPA through retroconversion (100).

Most studies show vegetarians, and particularly vegans, to
have lower blood levels of EPA and DHA than nonvegetarians
(101-104). The new Dietary Reference Intakes recommend intakes
of 1.6 and 1.1 grams of -linolenic acid per day for men
and women, respectively. These are designated as AIs rather
than RDAs. These recommendations assume some intake of
long-chain n-3 fatty acids and may not be optimal for vegetarians
who consume little if any DHA and EPA (35). The Joint
World Health Organization/Food Agriculture Organization
(WHO/FAO) Expert Consultation on Diet, Nutrition and the
Prevention of Chronic Diseases (105) recommends 5% to 8% of
calories from n-6 fatty acids and 1% to 2% of calories from n-3
fatty acids. Based on an energy intake of 2,000 kcal per day, this
would suggest a daily intake of 2.2 to 4.4 grams of n-3 fatty
acids. Those who do not receive a preformed source of EPA and
DHA require increased amounts of n-3 fatty acids. The recommended
ratio of n-6 to n-3 fatty acids is in the range of 2:1 to 4:1
(106-109).

It is recommended that vegetarians include good sources of

-linolenic acid in their diet (106,110). These would include
foods like flaxseed and flaxseed oil (see Table). Those with
increased requirements (eg, pregnant and lactating women or
those with diseases associated with poor essential fatty acid
status) or those at risk for poor conversion (eg, people with
diabetes) may benefit from direct sources of long-chain n-3
fatty acids, such as DHA-rich microalgae (100,106,111).
Iodine

Some studies suggest that vegans who do not consume iodized
salt may be at risk for iodine deficiency; this appears to be
particularly true for those living in iodine-poor areas
(29,112,113). Bread can be a source of iodine because some
dough stabilizers contain iodine. In the United States, about
50% of the general population uses iodized salt, whereas, in
Canada, all table salt is fortified with iodine. Sea salt and kosher
salt are generally not iodized nor are salty seasonings such as
tamari. Concern has been raised about vegetarian diets that
include foods, such as soybeans, cruciferous vegetables, and
sweet potatoes, that contain natural goitrogens. However,
these foods have not been associated with thyroid insufficiency
in healthy people provided iodine intake is adequate. The adult
RDA for iodine is easily met by one-half teaspoon of iodized salt
daily (44). Some vegetarians may have very high intakes of
iodine because of consumption of sea vegetables.

VEGETARIANISM THROUGHOUT THE LIFE CYCLE

Well-planned vegan, lacto-vegetarian, and lacto-ovo-vegetarian
diets are appropriate for all stages of the life cycle, including
pregnancy and lactation. Appropriately planned vegan, lactovegetarian,
and lacto-ovo-vegetarian diets satisfy nutrient
needs of infants, children, and adolescents and promote normal

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growth (36,114,115). Vegetarian diets in childhood and adolescence
can aid in the establishment of lifelong healthy eating
patterns and can offer some important nutritional advantages.
Vegetarian children and adolescents have lower intakes of cholesterol,
saturated fat, and total fat and higher intakes of fruits,
vegetables, and fiber than nonvegetarians (2,116-118). Vegetarian
children have also been reported to be leaner and to have
lower serum cholesterol levels (119-121).

Infants

When vegetarian infants receive adequate amounts of breast
milk or commercial infant formula and their diets contain good
sources of energy and nutrients such as iron, vitamin B-12, and
vitamin D, growth throughout infancy is normal. Extremely
restrictive diets such as fruitarian and raw foods diets have
been associated with impaired growth and therefore cannot be
recommended for infants and children (29).

Many vegetarian women choose to breastfeed their infants
(122), and this practice should be encouraged and supported.
The breast milk of vegetarian women is similar in composition
to that of nonvegetarians and is nutritionally adequate. Commercial
infant formulas should be used if infants are not breast-
fed or are weaned before 1 year of age. Soy formula is the only
option for vegan infants who are not being breastfed.

Soymilk, rice milk, homemade formulas, cows milk, and
goatís milk should not be used to replace breast milk or commercial
infant formula during the first year because these foods
do not contain the proper ratio of macronutrients nor do they
have appropriate micronutrient levels for the young infant.

Guidelines for the introduction of solid foods are the same for
vegetarian and nonvegetarian infants (115). When it is time for
protein-rich foods to be introduced, vegetarian infants can
have mashed or pureed tofu, legumes (pureed and strained if
necessary), soy or dairy yogurt, cooked egg yolks, and cottage
cheese. Later, foods such as cubes of tofu, cheese or soy
cheese, and bite-size pieces of soy burger can be started. Commercial,
full-fat, fortified soymilk, or cowís milk can be used as
a primary beverage starting at age 1 year or older for a child
who is growing normally and is eating a variety of foods (115).
Foods that are rich in energy and nutrients such as legume
spreads, tofu, and mashed avocado should be used when the
infant is being weaned. Dietary fat should not be restricted in
children younger than 2 years.

Breastfed infants whose mothers do not consume dairy products,
foods fortified with vitamin B-12, or B-12 supplements
regularly will need vitamin B-12 supplements (115). Guidelines
for the use of iron and vitamin D supplements in vegetarian
infants do not differ from guidelines for nonvegetarian infants.
Zinc supplements are not routinely recommended for vegetarian
infants because zinc deficiency is rarely seen (123). Zinc
intake should be individually assessed and zinc supplements or
zinc-fortified foods used during the time when complementary
foods are being introduced if the diet is low in zinc or mainly
consists of foods with low zinc bioavailability (124,125).

Children

Lacto-ovo-vegetarian children exhibit growth similar to that of
their nonvegetarian peers (114,119,126). Little information
about the growth of nonmacrobiotic vegan children is available,
although findings suggest that children tend to be slightly
smaller but within the normal ranges of the standards for
weight and height (114,122). Poor growth in children has been
seen primarily in those on very restricted diets (127).

Frequent meals and snacks and the use of some refined foods
(such as fortified breakfast cereals, breads, and pasta) and
foods higher in unsaturated fat can help vegetarian children
meet energy and nutrient needs. Average protein intake of
vegetarian children (lacto-ovo, vegan, and macrobiotic) generally
meets or exceeds recommendations, although vegetarian
children may consume less protein than nonvegetarian children
(116,128). Vegan children may have protein needs that
are slightly higher than those of nonvegan children because of
differences in protein digestibility and amino acid composition
of plant food proteins (36,129), but these protein needs are
generally met when diets contain adequate energy and a variety
of plant foods (35). Good sources of calcium, iron, and zinc
should be emphasized for vegetarian children along with dietary
practices that enhance absorption of zinc and iron from
plant foods. A reliable source of vitamin B-12 is important for
vegan children. If there is concern about vitamin D synthesis
owing to limited sunlight exposure, skin tone, season, or sunscreen
use, vitamin D supplements or fortified foods should be
used. The Table provides information about food sources of
nutrients. Food guides for vegetarian children under 4 years of
age (36,130) and for older children (72,73) have been published
elsewhere.

Adolescents

There are limited data available on the growth of vegetarian
adolescents, although studies suggest there is little difference
between vegetarians and nonvegetarians (131). In the West,
vegetarian girls tend to reach menarche at a slightly later age
than nonvegetarians (132,133), although not all research supports
this finding (134,135). If slightly later menarche does
occur, it may offer health advantages, including lower risk of
developing breast cancer and obesity (136,137). Vegetarian
diets appear to offer some nutritional advantages for adolescents.
Vegetarian adolescents are reported to consume more
fiber, iron, folate, vitamin A, and vitamin C than nonvegetarians
(2,60). Vegetarian adolescents also consume more fruits and
vegetables and fewer sweets, fast foods, and salty snacks compared
with nonvegetarian adolescents (2,118). Key nutrients
for adolescent vegetarians include calcium, vitamin D, iron,
zinc, and vitamin B-12.

Vegetarian diets are somewhat more common among adolescents
with eating disorders than in the general adolescent population;
therefore, dietetics professionals should be aware of
young clients who greatly limit food choices and who exhibit
symptoms of eating disorders (138,139). However, recent data
suggest that adopting a vegetarian diet does not lead to eating
disorders, rather that vegetarian diets may be selected to camouflage
an existing eating disorder (27,140,141). With guidance
in meal planning, vegetarian diets are appropriate and
healthful choices for adolescents.

Pregnant and Lactating Women

Lacto-ovo-vegetarian and vegan diets can meet the nutrient
and energy needs of pregnant women. Infants of vegetarian
mothers generally have birth weights that are similar to those
of infants born to nonvegetarians and to birth weight norms
(122,142,143). Diets of pregnant and lactating vegans should
contain reliable sources of vitamin B-12 daily. If there is concern
about vitamin D synthesis because of limited sunlight exposure,
skin tone, season, or sunscreen use, pregnant and lactating
women should use vitamin D supplements or fortified
foods. Iron supplements may be needed to prevent or treat

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iron-deficiency anemia, which is commonly seen during pregnancy.
Women capable of becoming pregnant and women in
the periconceptional period are advised to consume 400 g of
folate daily from supplements, fortified foods, or both in addition
to consuming food folate from a varied diet (92).

Infants of vegetarian mothers have been reported to have
lower cord and plasma DHA than do infants of nonvegetarians,
although the functional significance of this is not known
(104,143). Breast milk DHA levels in vegan and lacto-ovo-vegetarian
women appear to be lower than levels in nonvegetarians
(144). Because DHA seems to play a role in the development of
the brain and the eye and because a dietary supply of DHA may
be important for the fetus and newborn, pregnant and lactating
vegans and vegetarians (unless eggs are eaten regularly)
should include sources of the DHA precursor linolenic acid in
their diet (ground flaxseed, flaxseed oil, canola oil, soybean oil)
or use a vegetarian DHA supplement (from microalgae). Foods
containing linoleic acid (corn, safflower, and sunflower oil) and
trans-fatty acids (stick margarine, foods with hydrogenated
fats) should be limited because these fatty acids can inhibit
DHA production from linolenic acid (145).

Older Adults

Studies indicate that most older vegetarians have dietary intakes
that are similar to nonvegetarians (146,147). With aging,
energy needs decrease, but recommendations for several nutrients,
including calcium, vitamin D, vitamin B6, and possibly
protein, are higher. Sunlight exposure is often limited, and vitamin
D synthesis is decreased in older adults so that dietary or
supplemental sources of vitamin D are especially important.

Older adults may have difficulty with vitamin B-12 absorption
from food so vitamin B-12-fortified foods or supplements
should be used because the vitamin B-12 in fortified foods and
supplements is usually well absorbed (92). Protein requirements
for older adults are controversial. The current DRIs do
not recommend additional protein for older adults (35). A
metaanalysis of nitrogen balance studies concluded that there
is not enough evidence to recommend different protein intakes
for older adults but pointed out that the data are limited and
contradictory (34). Others have concluded that protein requirements
of older adults may be around 1 to 1.25 g/kg body
weight (148,149). Older adults can easily meet protein needs
on a vegetarian diet if a variety of protein-rich plant foods,
including legumes and soy products, are eaten daily.

Vegetarian diets, which are high in fiber, may be beneficial for
older adults with constipation. Older vegetarians may benefit from
nutritional counseling on foods that are easy to chew, require
minimal preparation, or are appropriate for therapeutic diets.

Athletes

Vegetarian diets can also meet the needs of competitive athletes.
Nutrition recommendations for vegetarian athletes
should be formulated with consideration of the effects of both
vegetarianism and exercise. The position of the American Dietetic
Association and Dietitians of Canada on nutrition and athletic
performance (39) provides appropriate dietary guidance
for athletes, although some modification may be needed to
address vegetariansí needs. Protein recommendations for endurance
athletes are 1.2 to 1.4 g/kg body weight, whereas resistance
and strength-trained athletes may need as much as 1.6
to 1.7 g/kg body weight (39). Not all groups support an increased
protein need for athletes (35). Vegetarian diets that
meet energy needs and contain a variety of plant-based protein

foods, such as soy products, other legumes, grains, nuts, and
seeds, can provide adequate protein without the use of special
foods or supplements (150). For adolescent athletes, special
attention should be given to meeting energy, protein, calcium,
and iron needs. Amenorrhea may be more common among vegetarian
than nonvegetarian athletes, although not all research
supports this finding (151,152). Female vegetarian athletes
may benefit from diets that include adequate energy, higher
levels of fat, and generous amounts of calcium and iron.

VEGETARIAN DIETS AND CHRONIC DISEASE

Obesity

Among Seventh-day Adventists (SDA), 40% of whom follow a
meatless diet, vegetarian eating patterns have been associated
with lower body mass index (BMI). In the Adventist Health
Study, which compared vegetarians and nonvegetarians within
the Adventist population, BMI increased as the frequency of
meat consumption increased in both men and women (4). In
the Oxford Vegetarian Study, BMI values were higher in non-
vegetarians compared with vegetarians in all age groups and for
both men and women (112).

In a study of 4,000 men and women in England comparing
the relationship between meat consumption and obesity
among meat eaters, fish eaters, lacto-ovo-vegetarians, and vegans,
mean BMI was highest in the meat eaters and lowest in the
vegans (153). BMI was lowest in those lacto-ovo-vegetarians
and vegans who had adhered to their diet for 5 years or longer.

Factors that may help to explain the lower BMI among vegetarians
include differences in macronutrient content (lower protein,
fat, and animal fat intake), higher fiber consumption, decreased
alcohol intake, and greater consumption of vegetables.

Cardiovascular Disease

An analysis of five prospective studies involving more than
76,000 subjects showed that death from ischemic heart disease
was 31% lower among vegetarian men compared with nonvegetarian
men and 20% lower among vegetarian women compared
with nonvegetarian women (154). Death rates were also
lower for vegetarian men and women compared with semivegetarians,
those who ate fish only or ate meat less than once per
week. Among SDA, vegetarian men had a 37% reduction in risk
of developing ischemic heart disease compared with nonvegetarian
men (4). In the only study to include vegan subjects,
risk for developing heart disease was even lower among SDA
vegan men than in the SDA lacto-ovo-vegetarians (155).

The lower rates of heart disease among vegetarians are explained
in part by their lower blood cholesterol levels. A review
of 9 studies found that, in comparison to nonvegetarians, lactoovo-
vegetarians and vegans had mean blood cholesterol levels
that were 14% and 35% lower, respectively (156). Although the
lower average BMI of vegetarians may help to explain this,
Sacks and colleagues found that, even when vegetarian subjects
were heavier than nonvegetarian subjects, the vegetarians
had markedly lower plasma lipoprotein values (157), and
Thorogood and colleagues found that differences in plasma
lipids in vegetarians, vegans, and meat eaters persisted, even
following adjustment for BMI (158). Some, but not all, studies
have shown lower high-density lipoprotein (HDL) levels in vegetarian
subjects (29). Lower HDL levels may be due to the type
or amount of dietary fat or to lower alcohol intake. This may
help to explain the smaller differences in heart disease rates
between vegetarian and nonvegetarian women because HDL

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may be a more important risk factor than LDL levels for women
(159). Average triglyceride levels tend to be similar in vegetarians
and nonvegetarians.

A number of factors in vegetarian diets may affect cholesterol
levels. Although studies show that most vegetarians do
not typically consume low-fat diets, saturated fat intake is considerably
lower among vegetarians than nonvegetarians, and
vegans have a lower ratio of saturated to unsaturated fat in
their diets (29). Vegetarians also consume less cholesterol than
nonvegetarians, although the range of intake varies considerably
across studies. Vegan diets are free of cholesterol.

Vegetarians consume between 50% and 100% more fiber
than nonvegetarians, and vegans have higher intakes than
lacto-ovo-vegetarians (29). Soluble fiber may lower risk for cardiovascular
disease by reducing blood cholesterol levels (160).
Limited research suggests that animal protein is directly associated
with higher serum cholesterol levels even when other
dietary factors are controlled (161). Lacto-ovo-vegetarians
consume less animal protein than nonvegetarians, and vegans
consume no animal protein. Research shows that consumption
of at least 25 g per day of soy protein, either in place of animal
protein or in addition to the usual diet, reduces cholesterol
levels in people with hypercholesterolemia (162). Soy protein
may also raise HDL levels (162). Vegetarians are likely to consume
more soy protein than the general population.

Other factors in vegetarian diets may impact cardiovascular
disease risk independent of effects on cholesterol levels. Vegetarians
have higher intakes of the vitamin antioxidants vitamins
C and E, which may reduce oxidation of LDL cholesterol.
Isoflavones, which are phytoestrogens found in soy foods, may
also have antioxidant properties (163) as well as enhancing
endothelial function and arterial compliance (164). Although
there is limited information available about intake of specific
phytochemicals among population groups, vegetarians appear
to consume more phytochemicals than nonvegetarians because
a greater percentage of their energy comes from plant
foods. Some phytochemicals may affect plaque formation
through effects on signal transduction and cell proliferation

(165) and may exert antiinflammatory effects (166). Research
from Taiwan found that vegetarians had significantly better
vasodilation responses, which correlated directly with years on
a vegetarian diet, suggesting a direct beneficial effect of vegetarian
diet on vascular endothelial function (167).
Not all aspects of vegetarian diets are associated with reduced
risk for heart disease. Some (89,103,168-171) but not all
(62,172) studies have found higher serum homocysteine levels
in vegetarians compared to nonvegetarians. Homocysteine is
believed to be an independent risk factor for heart disease.
Inadequate intake of vitamin B-12 may be the explanation. Vitamin
B-12 injections lowered homocysteine levels in vegetarians,
many of whom had low B-12 levels and high serum homocysteine
(173). In addition, low intakes of n-3 fatty acids and a
high ratio of n-6 to n-3 fatty acids in the diet may raise risk of
heart disease among some vegetarians (173).

There are only limited data on the role of vegetarian diets as
intervention for heart disease. Vegetarian diets used in these
studies have usually been very low in fat. Because these diets
have been used along with other lifestyle changes and they
have produced weight loss, it has not been possible to ascertain
any direct effect of adoption of vegetarian diet on risk factors
for heart disease or mortality. Vegetarian diets can be planned
to conform to standard recommendations for the treatment of
hypercholesterolemia.

Hypertension

Many studies show that vegetarians have both lower systolic
and diastolic pressures with differences between vegetarians
and nonvegetarians generally falling between 5 and 10 mm Hg
(29). In the Hypertension Detection and Follow-Up Program,
blood pressure reduction of just 4 mm Hg caused marked reduction
in mortality from all causes (174).

In addition to having lower blood pressures in general, vegetarians
have markedly lower rates of hypertension than meat
eaters (175,176). In one study, 42% of nonvegetarians had hypertension
(defined as 140/90 mm Hg) compared with only
13% of vegetarians. Even semivegetarians are 50% more likely
to have hypertension than vegetarians (4). Even when body
weights were similar between subjects, vegetarians had lower
blood pressures. Placing nonvegetarian subjects on a vegetarian
diet led to reduced blood pressure in normotensive (177)
and hypertensive subjects (178).

A number of studies have controlled for various factors that
might help to explain the lower blood pressures of vegetarians
and the hypotensive effects of changing to a vegetarian diet.
The lower blood pressures do not appear to be due to lower
BMI (175), exercise habits (179), absence of meat (180), milk
protein (181), fat content of diet (182), fiber (183) or differences
in potassium, magnesium, or calcium intakes (184). Because
sodium intake of vegetarians is comparable or only modestly
lower than that of nonvegetarians, sodium does not
explain the differences either. Suggested explanations include
a difference in blood glucose-insulin response because of a
lower glycemic index of vegetarian diets (185) or a collective
effect of beneficial compounds from plant foods (186).

Diabetes

Vegetarian diets can meet guidelines for the treatment of diabetes
(187), and some research suggests that diets that are
more plant-based reduce risk for type 2 diabetes. Rates of self-
reported diabetes among Seventh-day Adventists (SDA) were
less than half those of the general population, and, among SDA,
vegetarians had lower rates of diabetes than nonvegetarians
(188). In the Adventist Health Study, age-adjusted risk for developing
diabetes for vegetarian, semivegetarian, and nonvegetarian
men was 1.00, 1.35, and 1.97, respectively, and, for
women, it was 1.00, 1.08, and 1.93 (4). Among the possible
explanations for a protective effect of vegetarian diet are the
lower BMI of vegetarians and higher fiber intake, both of which
improve insulin sensitivity. However, among men in the Adventist
Health Study, risk for diabetes was still 80% higher in
nonvegetarian men after adjustment for weight. In men, meat
consumption was directly associated with increased risk of diabetes.
Among women, risk increased only when meat consumption
exceeded five servings per week (188).

Cancer

Vegetarians have an overall lower cancer rate compared with
the general population, but it is not clear to what extent this is
due to diet. When nondietary cancer risk factors are controlled
for, differences in overall cancer rates between vegetarians and
nonvegetarians are greatly reduced, although marked differences
remain in rates of certain cancers. An analysis from the
Adventist Health Study that controlled for age, sex, and smoking
found no differences between vegetarians and nonvegetarians
for lung, breast, uterine, or stomach cancer but did find
that nonvegetarians had a 54% increased risk for prostate cancer
and an 88% increased risk for colorectal cancer (4). Other

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research has shown lower rates of colon cell proliferation in
vegetarians compared with nonvegetarians (189) and lower
levels of serum insulin-like growth factor-I, thought to be involved
in the etiology of several cancers in vegans compared
with both nonvegetarians and lacto-ovo-vegetarians (190).
Both red and white meat have been independently linked to
increased risk for colon cancer (4). Observational studies have
found an association between high intake of dairy foods and
calcium with increased risk for prostate cancer (191-193), although
not all studies support this finding (194). A pooled
analysis of 8 observational studies found no link between meat
or dairy consumption and breast cancer (195).

Research suggests that a number of factors in vegetarian
diets may impact cancer risk. Vegetarian diets come closer to
matching the dietary guidelines issued by the National Cancer
Institute than do nonvegetarian diets, particularly in regard to
fat and fiber intakes (196). Although data on fruit and vegetable
intake of vegetarians are limited, a recent study found that
intake was considerably higher among vegans compared with
nonvegetarians (62). High lifetime exposure to estrogen has
been linked to increased breast cancer risk. Some research
shows that vegetarians have lower serum and urinary estrogen
levels (197). There is also some evidence that vegetarian girls
begin menstruation at a later age, which may reduce cancer
risk because of lower lifetime estrogen exposure (132,133).
High fiber intake is believed to protect against colon cancer,
although not all research supports this (198,199). The environment
of the colon of vegetarians is strikingly different from that
of nonvegetarians. Vegetarians have a lower concentration of
potentially carcinogenic bile acids (200) and fewer intestinal
bacteria that convert the primary bile acids into carcinogenic
secondary bile acids (201). More frequent elimination and the
levels of certain enzymes in the colon enhance elimination of
potential colon carcinogens (200,202). Most research shows
that vegetarians have lower levels of fecal mutagens (203).

Vegetarians do not consume heme iron, which has been
shown to lead to the formation of highly cytotoxic factors in the
colon increasing colon cancer risk (204). Finally, vegetarians
most likely have higher intakes of phytochemicals, many of
which have anticancer activity. Isoflavones in soy foods have
been shown to have anticancer effects, particularly in regard to
breast and prostate cancer, although this is not supported by all
research (205,206).

Osteoporosis

Osteoporosis is a complex disease affected by a variety of lifestyle,
dietary, and genetic factors. Although some data indicate
that osteoporosis is less common in developing countries with a
mostly plant-based diet, these studies have relied on hip fracture
data, which has been found to be unreliable for comparing
bone health across cultures. There is little evidence to suggest
that bone mineral density differs between western nonvegetarians
and lacto-ovo-vegetarians.

A number of studies have shown that high protein intake,
from animal foods in particular, causes increased excretion of
calcium and raises calcium needs (207-209). The effect is believed
to be due to the increased acid load from metabolism of
sulfur-containing amino acids (SAA). However, grains are also
high in these amino acids, and some research shows that SAA
intake was similar between nonvegetarians and vegetarians
(210). Despite this, there is some evidence that postmenopausal
women with diets high in animal protein and low in plant
protein had a high rate of bone loss and a greatly increased risk

of hip fracture (211). Although excessive protein intake may
compromise bone health, there is evidence that low protein
intakes could raise risk for poorer bone health (212). Although
there are very little reliable data on bone health of vegans, some
studies suggest that bone density is lower among vegans compared
with nonvegetarians (213-215). Vegan women, like other
women, may have low calcium intakes despite the availability of
nondairy sources of well-absorbed calcium. Some vegan
women may also have protein intakes that are marginal, and
vitamin D status has shown to be compromised in some vegans
(216-218). The lower serum estrogen levels of vegetarians may
be a risk factor for osteoporosis. In contrast, short-term clinical
studies suggest that soy protein rich in isoflavones decreases
spinal bone loss in postmenopausal women (219). Higher intake
of potassium and vitamin K among vegetarians may also
help to protect bone health. However, the data suggest that a
vegetarian diet does not necessarily protect against osteoporosis
despite lower animal protein content.

Renal Disease

High intake of dietary protein may worsen existing kidney disease
or increase risk for those who are susceptible to this disease
because protein intake is associated with a higher glomerular
filtration rate (GFR) (220). The GFR of healthy
vegetarians is lower than that of nonvegetarians and even lower
in vegans (221). The type of protein consumed may also have
an effect, with plant foods having a more beneficial effect on
GFR than animal protein (222, 223). GFR was 16% higher in
healthy subjects after eating a meal containing animal protein
compared with a meal with soy protein (222). Because the
pathology of renal disease is similar to that of atherosclerosis,
the lower serum cholesterol levels and reduced cholesterol oxidation
resulting from a vegetarian diet may be beneficial for
those with kidney disease.

Dementia

Although rates of dementia differ markedly throughout the
world, differences in diagnostic criteria make cross-cultural
comparisons difficult. In the United States, among SDA, those
who ate meat were more than twice as likely to develop dementia
(224). Those who had eaten meat for many years were more
than three times as likely to develop signs of dementia. Diets
high in antioxidants have been found to protect cognitive function
(225-227). The lower blood pressure of vegetarians may
also be protective. There is also some evidence that lower blood
cholesterol protects against dementia (228). Higher homocysteine
levels are linked to increased risk of dementia, and this
may present one risk factor for vegetarians who do not get
adequate vitamin B-12 (229-232). Although one observational
study found an increased rate of dementia among Japanese
American men who ate tofu regularly (233), the study had a
number of methodological limitations, and other research has
not supported these findings (234).

Other Health Effects of Vegetarian Diets

Diverticular disease

Gear and colleagues found that both male and female vegetarians
aged 45 to 59 years were 50% as likely to have diverticulitis
compared with nonvegetarians (235). Although fiber is believed
to be the most important reason for this difference, other
factors may have an effect as well. High-fat diets, independent
of fiber intake, have been associated with increased risk of

758 / June 2003 Volume 103 Number 6

ADA REPORTS

diverticulitis (236). Meat intake may also increase risk (236).
Older research suggests that meat consumption may promote
growth of bacteria that produce a toxic metabolite that weakens
the wall of the colon (237).

Gallstones

In a study of 800 women aged 40 to 69 years, nonvegetarians were
more than twice as likely as vegetarians to suffer from gallstones
(238). The relationship held even after controlling for the three
known risk factors for gallstones: obesity, gender, and aging.

Rheumatoid arthritis

Rheumatoid arthritis (RA), believed to be an autoimmune disease,
involves inflammation of the joints. Several studies from one
group of researchers in Finland suggest that fasting, followed by
vegan diet, may be useful in treatment of RA (239,240).

Although data are very limited and more follow-up is needed
before conclusions can be drawn, some studies suggest that a
mostly raw foods vegan diet reduces symptoms of fibromyalgia

(241) and that a vegetarian diet may reduce symptoms of topical
dermatitis (242).
PROGRAMS AND AUDIENCES IMPACTED

Special Supplemental Nutrition Program for Women,
Infants, and Children

In the United States, the Special Supplemental Nutrition Program
for Women, Infants, and Children (WIC) is a federal grant
program that serves pregnant, postpartum, and breastfeeding
women and infants and children up to 5 years of age who are
documented as being at nutritional risk and with family income
below state standards. This program provides checks or coupons
to purchase some foods suitable for vegetarians, including
infant formula, iron-fortified infant cereal, vitamin C-rich fruit
or vegetable juice, carrots, cowís milk, cheese, eggs, iron-fortified
ready-to-eat cereal, dried beans or peas, and peanut butter.
Individual state agencies are allowed to submit a plan to
USDAís Food and Nutrition Service for substitution of foods to
allow for different cultural eating patterns, provided the proposed
substitute food is nutritionally equivalent or superior to
the food it replaces, is widely available, and does not cost more
than the food it is to replace (243). This provision could possibly
allow more foods suitable for vegans to be purchased.

Canada Prenatal Nutrition Program (CPNP), federally
funded by Health Canada, and perinatal community programs
provide vouchers, coupons, or groceries to those who meet the
income and nutritional risk criteria for the program. Vouchers
can be used for some foods acceptable to vegetarians, including
milk, juice, cheese, eggs, fortified soymilk, and other foods (244).

Child Nutrition Programs

In the United States, the National School Lunch Program
(NSLP) allows nonmeat protein products, including certain soy
products, cheese, eggs, cooked dried beans or peas, yogurt,
peanut butter, other nut or seed butters, peanuts, tree nuts,
and seeds to be used (245,246). USDA information for school
foodservice personnel includes several vegetarian and vegan
quantity recipes (247). Few public schools regularly feature
vegetarian menu items. School lunches are not adequate for
vegans even when some vegan options are available because
soymilk can only be served as a part of school lunch in cases of
documented lactose intolerance.

In Canada, school lunch, breakfast, and snack programs;
food selection standards; and provision for vegetarian meals
vary from one region to another. Nationally, the Canadian Living
Foundationís Breakfast for Learning program is developing
Best Practice Program Standards for breakfast, snack, and
lunch programs. Vegetarian meals based on Canadaís Food
Guide to Healthy Eating fit within this framework (248).

Feeding Programs for the Elderly

The federal Elderly Nutrition Program (ENP) distributes funds
to states, territories, and tribal organizations for a national network
of programs that provide congregate and home-delivered
meals (often known as Meals on Wheels) for older Americans.
Meals served under this program must provide at least one-
third of the RDAs (249). Meals are often provided by local
Meals on Wheels agencies. A 4-week set of vegetarian menus
has been developed for use by the National Meals on Wheels
Foundation (250,251).

Corrections Facilities

Court rulings in the United States and Canada have granted
prison inmates the right to have vegetarian meals for religious
and medical reasons (and in Canada, by choice, as well)
(252,253). Federal institutions and those for many states and
provinces provide vegetarian options for meals. The Canadian
federal court has ruled that prison inmates who are opposed to
eating meat have a constitutional right to be served vegetarian
meals. The Freedom of Conscience provisions in the Charter of
Rights allow prisoners to demand vegetarian fare for moral
reasons, just as other inmates may request special meals on
religious or medical grounds (252).

Military/Armed Forces

The US Armyís Combat Feeding Program, which oversees all
food regulations, provides a choice of vegetarian menus (254).
Canadian Forces Food Services offers one or more vegetarian
options at every meal (255). An estimated 10% to 15% of Canadian
Forces members choose vegetarian meals for combat
rations (individual meal packs) (256).

Other Institutions and Quantity Food Service
Organizations

Other institutions, including colleges, universities, hospitals,
restaurants, and publicly funded museums and parks offer
varying amounts and types of vegetarian selections. Resources
are available for vegetarian quantity food preparation (Figure
1). As interest in vegetarianism grows and because of the nutritional
and health benefits of choosing a vegetarian diet, increased
provision of vegetarian meals on a daily basis should be
encouraged.

ROLE OF DIETETICS PROFESSIONALS

Vegetarian clients may seek nutrition counseling services for a
specific clinical condition or for assistance in planning healthful
vegetarian diets. They may sometimes be referred because of
problems related to poor diet choices. Dietetics professionals
have an important role in supporting clients who express an
interest in adopting vegetarian diets or who already eat a vegetarian
diet. It is important for dietetics professionals to support
any client who chooses this style of eating and to be able to
give current accurate information about vegetarian nutrition.
Information should be individualized depending on type of vegetarian
diet, age of the client, food preparation skills, and ac-

Journal of THE AMERICAN DIETETIC ASSOCIATION / 759

ADA REPORTS

tivity level. It is important to listen to the clientís own description
of his or her diet to ascertain which foods can play a role in
meal planning. Figure 1 provides a listing of Web resources on
vegetarianism. Figure 2 includes meal planning tips.

Qualified dietetics professionals can help vegetarian clients
in the following ways:

provide information about meeting requirements for vitamin
B-12, calcium, vitamin D, zinc, iron, and n-3 fatty acids because
poorly planned vegetarian diets may sometimes fall short of
these nutrients;
give specific guidelines for planning balanced lacto-ovo-vegetarian
or vegan meals for all stages of the life cycle;
adapt guidelines for planning balanced lacto-ovo-vegetarian
or vegan meals for clients with special dietary needs because of
allergies or chronic disease or other restrictions;
be familiar with vegetarian options at local restaurants;
provide ideas for planning optimal vegetarian meals while
traveling;
instruct clients about the preparation and use of foods that
frequently are part of vegetarian diets; the growing selection of
products aimed at vegetarians may make it impossible to be
General Vegetarian Nutrition:

Food and Nutrition Information Center, USDA

http://www.nal.usda.gov/fnic/etext/000058.html
http://www.nal.usda.gov/fnic/pubs/bibs/gen/vegetarian.htm

Loma Linda University Vegetarian Nutrition & Health Letter

http://www.llu.edu/llu/vegetarian/vegnews.htm

Seventh-day Adventist Dietetic Association

http://www.sdada.org/facts&fiction.htm

Vegan Outreach
http://www.veganoutreach.org/whyvegan/health.html;

http://www.veganoutreach.org/health/stayinghealthy.html

The Vegan Society (vitamin B-12)

www.vegansociety.com/html/info/b12sheet.htm

Vegetarian Nutrition Dietetic Practice Group

http://www.vegetariannutrition.net/

Vegetarian Resource Group

http://www.vrg.org/

The Vegetarian Society of the United Kingdom

http://www.vegsoc.org/health/

VegRD

http://vegrd.vegan.com/

Travel:

Happy Cowís Global Guide to Vegetarian Restaurants

www.happycow.net/

VegDining.com

www.vegdining.com/Home.cfm

Vegetarian Resource Group

www.vrg.org/travel/

Quantity Food Preparation:

Vegetarian Resource Group

http://www.vrg.org/fsupdate/

FIG 1. Useful Web sites.

A variety of menu planning approaches can provide adequate
nutrition for vegetarians. The Vegetarian Food Guide Pyramid
and Vegetarian Food Guide Rainbow (72,73) suggest one approach.
In addition, the following guidelines can help vegetarians
plan healthful diets:

¶
Choose a variety of foods including whole grains, vegetables,
fruits, legumes, nuts, seeds, and if desired, dairy products,
and eggs.
¶
Choose whole, unrefined foods often and minimize the intake
of highly sweetened, fatty and heavily refined foods.
Choose a variety of fruits and vegetables.
¶
If animal foods such as dairy products and eggs are used,
choose lower-fat dairy products and use both eggs and dairy
products in moderation.
¶
Use a regular source of vitamin B-12 and, if sunlight exposure
is limited, of vitamin D.
FIG 2. Meal planning.

knowledgeable about all such products. However, practitioners
working with vegetarian clients should have a basic knowledge
of preparation, use, and nutrient content of a variety of grains,
beans, soy products, meat analogs and fortified foods.

be familiar with local sources for purchase of vegetarian foods.
In some communities, mail order sources may be necessary.
work with family members, particularly the parents of vegetarian
children, to help provide the best possible environment
for meeting nutrient needs on a vegetarian diet; and,
if a practitioner is unfamiliar with vegetarian nutrition, he/she
should assist the individual in finding someone who is qualified
to advise the client or should direct the client to reliable resources.
CONCLUSIONS

Appropriately planned vegetarian diets have been shown to be
healthful, nutritionally adequate, and beneficial in the prevention
and treatment of certain diseases. Vegetarian diets are
appropriate for all stages of the life cycle. There are many
reasons for the rising interest in vegetarianism. The number of
vegetarians in the United States and Canada is expected to
increase over the next decade. Dietetics professionals can assist
vegetarian clients by providing current, accurate information
about vegetarian nutrition, foods, and resources.

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