The official position of the American Dietetic Association (ADA) is as follows: a properly planned vegetarian diet is complete and beneficial for the prevention and treatment of certain diseases.
Vegetarianism in perspective
Vegetarian diets can vary greatly. A lacto-ovo vegetarian diet consists of fruits, vegetables, grains, legumes, seeds, nuts, dairy products, and eggs. It excludes meat, fish, and poultry. A vegan, or strict vegetarian, diet differs from lacto-ovo vegetarianism by the absence of eggs, dairy products, and other animal foods. But even within this framework, different people to varying degrees refuse animal products. Therefore, in order to accurately determine the nutritional qualities of a vegetarian diet, it must be considered specifically.
Studies show that vegetarians often have lower morbidity and mortality from certain chronic degenerative diseases than non-vegetarians. Non-dietary factors such as physical activity and abstaining from smoking and alcohol may also play a role, but diet is the most important factor.
People are switching to vegetarianism not only for medical reasons, but also for environmental reasons and world hunger. Also among the reasons why people become vegetarians: economic considerations, ethical issues, religious beliefs.
Consumer demand for vegetarian products is leading to an increase in catering establishments offering vegetarian products. Currently, most university canteens offer vegetarian meals.
The Importance of Vegetarianism for Health
A vegetarian diet low in fat, or saturated fat, has been successfully used as part of a comprehensive health advocacy program to reverse the current coronary artery disease landscape. Vegetarian diets are useful for prevention because they are lower in saturated fat, cholesterol, and animal protein, higher in folate, which lowers serum homocysteine, antioxidants such as vitamins C and E, carotenoids, and phytochemicals.
Vegetarianism stops the development of coronary heart disease and reduces mortality from coronary artery disease. Vegetarians generally have lower total cholesterol and low-density lipoprotein levels, but high-density lipoprotein and triglyceride levels vary with the type of vegetarian diet.
Vegetarians are less prone to hypertension than non-vegetarians. This effect appears to occur regardless of body weight and sodium intake. Vegetarians are much less likely to die from type 2 diabetes, possibly due to their higher intake of complex carbohydrates and lower body mass index.
Vegetarians are less prone to lung cancer and colon cancer. The reduced risk of colorectal cancer is associated with an increased intake of fiber, vegetables, and fruits. The colon microflora in vegetarians is markedly different from that of non-vegetarians, which reduces the risk of colon cancer.
There is no decrease in breast cancer among Western vegetarians, but data from ethnic comparisons indicate that the risk of breast cancer is lower in populations with plant-based diets. A protective factor may be lower estrogen levels in vegetarians.
A well-planned vegetarian diet can be helpful in preventing and treating kidney disease. Clinical studies and animal modeling have shown that certain plant proteins can increase the chance of survival and reduce proteinuria, glomerular filtration rate, renal blood flow, and histological damage to the kidneys when compared to a non-vegetarian diet.
Vegetarian Diet Analysis
The necessary amount of important amino acids can be obtained from plant-based protein sources, provided that the plant-based diet is varied and contains sufficient calories. The study shows that supplemental protein supplementation is not required, and daily intake of a variety of amino acid sources ensures normal nitrogen retention and utilization in healthy individuals.
Although vegetarian diets have lower total protein and may need to increase slightly due to the lower quality of some plant proteins, both lacto-ovo vegetarians and vegans get enough protein.
Plant foods contain only non-heme iron, which is more sensitive than heme iron to inhibitors (retarders) and iron absorption enhancers. Although vegetarian diets are generally higher in iron than non-vegetarian diets, iron stores in vegetarians are lower because plant-based iron is less absorbed. But the clinical significance of this phenomenon, if any, is unclear, because the incidence of iron deficiency anemia is the same in vegetarians and meat eaters. Iron absorption may be improved by a higher vitamin C content.
Plant foods may contain vitamin B12 on their surface in the form of soil residue, but this is not a reliable source of B12 for vegetarians. Much of the vitamin B12 found in spirulina, seaweed, sea vegetables, tempeh (a fermented soy product), and miso has been shown to be more of an inactive B12 analog than a complete vitamin.
Although dairy products and eggs contain vitamin B12, research shows low blood levels of vitamin B12 in lacto-ovo vegetarians. Vegetarians who avoid or limit food of animal origin are advised to consume nutritional supplements or foods fortified with vitamin B12. Since the human body requires very little vitamin B12, and its stores are stored and reused, it can take many years for symptoms of a deficiency to appear. Vitamin B12 absorption decreases with age, so supplementation is recommended for all older vegetarians.
Lacto-ovo vegetarians get enough calcium, as much or more than non-vegetarians. However, vegans get less calcium than lacto-ovo vegetarians and mixed dieters. It should be noted that vegans may require less calcium than non-vegetarians, because diets with less protein and more alkaline foods conserve calcium. In addition, when a person eats a diet low in protein and sodium and has sufficient exercise, their calcium requirements may be lower than those who lead a sedentary lifestyle and eat standard Western diets. These factors, as well as genetic predisposition, help explain why bone health is sometimes independent of calcium intake.
Since it has not yet been established how much calcium vegans need, and given that its deficiency leads to osteoporosis in women, vegans should consume as much calcium as the Institute of Medicine has established for their age group. Calcium is well absorbed from many plant foods, and vegan diets contain enough of this element if calcium-rich foods are regularly included in them. In addition, many new vegetarian foods are fortified with calcium. If vegans are not getting the calcium they need from food, dietary supplements are recommended.
Vitamin D is deficient in food (both vegetarian and non-vegetarian diets) unless it includes foods fortified with vitamin D. Vegan diets may be deficient in this nutrient, as its most common source is cow’s milk fortified with vitamin D. But now you can buy vegan foods with added vitamin D, such as soy milk and some cereal products. In addition, studies show that the body receives the main dose of vitamin D from exposure to sunlight, and that it is important to get it from food only when a person does not get much sun. It is believed that to get enough vitamin D, it is enough to expose the sun to the hands, shoulders and face for 5-15 minutes a day. People with dark skin, as well as those who live in northern latitudes, cloudy or smoky areas, probably need to spend more time in the sun. The synthesis of vitamin D is hindered by the use of sunscreen. If vegans have little sun exposure, vitamin D supplements are recommended. This is especially true for older people, whose bodies synthesize vitamin D less efficiently.
Studies show that zinc intake in vegetarians is lower or the same as in non-vegetarians. Most studies show that vegetarians have normal levels of zinc in their hair, serum, and saliva. With diets poor in zinc, compensation mechanisms may help vegetarians. But, since zinc is low in plant foods, and the consequences of zinc deficiency are not yet fully understood, vegetarians should eat as much zinc as recommended in the intake, or even more.
Egg- and fish-free diets are low in omega-3 fatty acids (docosehexaacid, or DHA). Vegetarians have lower blood lipid levels of this fatty acid, although not all studies agree with this statement. One vital fatty acid, linoleic acid, can be converted to DHA, although conversion levels appear to be inefficient and high linoleic acid intake prevents this conversion (36). The impact of low DHA has not been studied. But vegetarians are advised to include good sources of linoleic acid in their diet.
Vegetarianism in different age periods of life.
A balanced vegan or lacto-ovo vegetarian diet is suitable for all stages of life, including during pregnancy and lactation. It also meets the nutritional needs of infants, children and adolescents and contributes to their normal growth.
Nutritional deficiencies are most likely in people with a very restricted diet. All vegan children should have a reliable source of vitamin B12 and, if they have little sun exposure, receive vitamin D supplements or vitamin D-fortified foods. The diet should include foods rich in calcium, iron, and zinc. Meal the energy needs of vegetarian children help frequent meals and small snacks, as well as some refined and high-fat foods. The basic principles regarding nutritional supplementation of iron, vitamin D, and the introduction of solid foods into the diet are the same for normal and vegetarian infants.
When it’s time to introduce protein into the diet, vegetarian babies can get peeled tofu, cottage cheese, and beans (peeled and mashed). Vegan infants still breastfed should receive vitamin B12 if the mother’s diet is deficient, and vitamin D if they get little sun exposure.
Vegetarianism is somewhat more common among adolescents with eating disorders, so nutritionists should be aware of adolescents who are very restrictive in their food choices and who show signs of eating disorders. However, according to current data, Going vegan does not in itself lead to eating disorders.. If the diet is properly planned, vegetarianism is the right and healthy choice for teenagers.
Vegetarian diets also meet the needs of athletes during the competition period. Protein may need to be increased because exercise increases amino acid metabolism, but vegetarian diets that cover energy costs and have good sources of protein (eg, soy products, beans) can provide the protein you need without the use of special foods or supplements.
Young athletes should pay special attention to the calorie content of food, protein and iron. Vegetarian athletes may be more likely to have amenorrhea than non-vegetarian athletes, although not all studies support this observation.
One way to maintain normal menstrual cycles could be to eat a higher calorie, higher fat, lower fiber diet, and reduce the intensity of your workouts. Lacto-ovo vegetarian and vegan diets can meet the nutrient and energy needs of pregnant women. The body weight of newborns who were born to well-nourished vegetarians is normal.
Pregnant and breastfeeding vegans should supplement their diet with 2.0 to 2.6 micrograms of vitamin B12 daily. And, if the woman doesn’t get much sun exposure, 10 micrograms of vitamin D daily. Folate supplements are recommended for all pregnant women, although vegetarian diets generally contain more folate than non-vegetarian diets.
A variety of approaches to menu planning will help ensure adequate nutrition for vegetarians. In addition, the following guidelines can help vegetarians plan healthy diets: * Choose a variety of foods, including whole grains, vegetables, fruits, beans, nuts, seeds, dairy, and eggs. * Choose whole, unrefined foods more often, and limit foods high in sugar, fat, and highly refined foods. * Choose from a variety of fruits and vegetables. * If you are using animal products – dairy and eggs – choose those that have a lower fat content. Limit cheeses and other high-fat dairy products and eggs because they are high in saturated fats and because they reduce plant foods. * Vegans should regularly include vitamin B12 in their meals, as well as vitamin D if sun exposure is limited. * Breastfed-only infants from 4-6 months of age should receive iron supplements and, if sun exposure is limited, vitamin D supplements. Also vitamin B12 supplements if the mother’s diet is deficient in this vitamin. * Do not restrict fat in the diet of children under 2 years of age. And to help older children get enough energy and nutrients, include foods high in unsaturated fats (such as nuts, seeds, nut and seed oils, avocados, and vegetable oils) in the diet.
Food pyramid for planning a vegan and vegetarian diet
FATS, OILS, AND SWEET FOOD eat limited amounts of hard candy, butter, margarine, salad dressing and frying oil.
MILK, YOGURTS AND CHEESE 0-3 servings per day milk – 1 cup yogurt – 1 cup plain cheese – 1/1 *Vegetarians who do not use milk, yogurt and cheese should choose other calcium-rich sources.
DRY BEANS, NUTS, SEEDS, EGGS, AND MEAT SUBSTITUTES 2-3 servings a day soy milk – 1 cup cooked dried beans or peas – 1/2 cup 1 egg or 2 egg whites nuts or seeds – 2 tbsp. tofu or tempeh – 1/4 cup peanut butter – 2 tablespoons
VEGETABLES 3-5 servings per day boiled or chopped raw vegetables – 1/2 cup raw leafy vegetables – 1 cup
FRUIT 2-4 servings per day juice – 3/4 cup dried fruit – 1/4 cup chopped, raw fruit – 1/2 cup canned fruit – 1/2 cup 1 medium sized fruit such as banana, apple or orange
BREAD, CEREAL, RICE, PASTA 6-11 servings per day bread – 1 slice cooked cereals – 1/2 cup boiled rice, pasta, or other grains – 1/2 cup flour products – 1/2 cup
______ Published in Journal of the American Dietetic Association, November 1997, Volume 97, Issue 11 Authors – Virginia K. Messina, MPH, RD, and Kenneth I. Burke, PhD, RD Reviewers – Winston J. Craig, PhD, RD; Johanna Dwyer, DSc, RD; Suzanne Havala, MS, RD, FADA; D. Enette Larson, MS, RD; A. Reed Mangels, PhD, RD, FADA; Vegetarian Nutrition dietetic practice group (Lenore Hodges, PhD, RD; Cyndi Reeser, MPH, RD) Translated into Russian by Mikhail Subbotin