II. Definitions

  1. Vegetarian Diet
    1. Plant based diet consisting of fruits, vegetables, dried beans, peas, grains, seeds and nuts
    2. Vegetarian Diets typically typically exclude meat, poultry, fish and animal fats
    3. Flexitarians may add certain meats, such as fish and seafood (pescatarians) or poultry
    4. Vegans exclude dairy, eggs, and honey, while Lacto-Ovo-Vegetarians eat milk and eggs
  2. Vegan diet
    1. Vegetarian Diet that excludes all animal products, including dairy, eggs, and honey in addition to meat, poultry, fish and animal fats
    2. Vegans also avoid any animal products in general (cosmetics, animal-based clothing)
  3. Lacto-Ovo-Vegetarian Diet
    1. Vegetarian Diet that includes dairy products and eggs
  4. Plant Forward Diet
    1. Diet in which the meat main course is replaced by Vegetarian entrees which may include meat as a smaller portion of the meal

III. Epidemiology

  1. Worldwide Prevalence
    1. Asia: 19% (esp. India, where 40% are Vegetarian, related to hinduism)
    2. Africa and Middle East: 16%
    3. Central America and South America: 8%
    4. North America: 6% overall (2-3% of teens)
    5. Europe: 5%

IV. Indications: Vegetarian Diet

  1. Religion (e.g. Hinduism)
  2. Healthy Diet
    1. High fiber diet
    2. Diverse gut microbiome
      1. Associated with antiinflammatory effects and improved gut health
      2. Singh (2017) J Transl Med 15:73 [PubMed]
    3. Increased Plant Sterol intake, lower saturated fat intake and lower Cholesterol intake
      1. Bradbury (2015) Eur J Clin Nutr 69:1180 [PubMed]
    4. Reduced cardiovascular disease risk (Ischemic Heart Disease, Cerebrovascular Disease)
      1. Matsumoto (2019) J Nutr Sci 8:e6 [PubMed]
      2. Ornish (1998) JAMA 280:2001-7 [PubMed]
      3. Tong (2019) BMJ 366:14897 [PubMed]
    5. Lower risk of Hypertension (e.g. DASH Diet)
      1. Yokoyama (2014) JAMA Intern Med 174:577-87 [PubMed]
    6. Decreased Caloric Intake and lower Obesity Risk (reduced BMI, reduced Waist Circumference)
      1. Barnard (2015) J Acad Nutr 954-69 [PubMed]
    7. Improved glycemic control and lower Diabetes Mellitus risk
      1. Toumpanakis (2018) BMJ Open Diabetes Res Care 6:e000534 [PubMed]
    8. Improved quality of life, physical and emotional well being and Major Depression
    9. Cancer Prevention and decreased cancer-associated mortality (phytochemical intake, avoidance of red meat, processed meats)
      1. Aune (2016) BMC Med 14:207 [PubMed]
  3. Ethical concerns
    1. Animal slaughter
    2. Environmental impact (e.g. greenhouse gas or GHG emissions related to meat industry, other polutants)
      1. Example: Tofu requires 74 fold less land and 8 fold less water than equivalent beef Protein (25 fold less GHG emissions)
      2. https://ourworldindata.org/environmental-impacts-of-food

V. Management: Vegetarian Diet

  1. Examples of Plant Forward Diets common to medical studies
    1. Mediterranean Diet
    2. Dietary Approaches to Stop Hypertension (DASH Diet)
  2. Dietary Supplementation (esp. for Vegan diets)
    1. Dietary Iron (esp. in women of menstruating age)
    2. Dietary zinc (e.g. nuts, seeds, grains, legumes, tofu, dairy)
    3. Dietary Iodine (e.g. Iodized Salt, seafood, dairy products)
    4. Omega-3 Fatty Acid (e.g. flaxseed, chia seed, hemp seed, walnuts or Omega-3 Fatty Acid Supplements)
    5. Vitamin B12 (e.g. dairy, fortified cereals and other fortified foods, or daily Vitamin B12 supplement)
      1. Other plant based sources (e.g. fermented soy, seaweed, mushrooms, leafy vegetables) are inadequate for daily B12 needs
    6. Osteoporosis Prevention
      1. Ensure adequate Dietary Calcium intake
      2. Ensure adequate Vitamin D intake
    7. Vegetable Protein intake is typically adequate
      1. Protein-rich plant based foods include legumes, soy (e.g. tofu, tempeh), nuts and seeds
      2. Omnivores of North America and Europe ingest up to 2 times animal based Protein RDA (excessive, Obesity)
  3. Additional topics
    1. Eating Disorders
      1. Eating Disorder (e.g. Anorexia Nervosa) risk is not increased by prior Vegetarian or Vegan diet
      2. However, patients with disordered eating may select Vegetarian or Vegan diets as socially appropriate way to avoid food
      3. Be alert for underlying Eating Disorders, but avoid labelling typical Vegetarian Diets as restrictive when Caloric Intake is adequate
      4. Timko (2012) Appetite 58:982-90 [PubMed]
    2. Athletes
      1. Vegetarian Diets offer adequate Nutrition for Athletes
      2. Ensure adequate Caloric Intake
        1. Be alert for Relative Energy Deficiency in Sport
        2. Ensure adequate Calcium and Vitamin D in female endurance athletes with Amenorrhea (see Female Athlete Triad)
      3. Ensure adequate Protein (e.g. soy, legumes, nuts, seeds)
        1. Milk and eggs (if not vegan) may help supplement plant based intake in athletes
        2. Creatine supplementation may be considered in sprinters and Resistance Training
      4. As with all Vegetarians and vegans, ensure adequate dietary Vitamin intake (iron, zinc, Iodine, Vitamin B12, Calcium, Vitamin D)
        1. Encourage iron rich foods in female athletes
      5. Craddock (2016) Int J Sports Nutr Exerc Metab 26:212-20 [PubMed]
    3. Pregnancy and Lactation
      1. Vegetarian and Vegan diets offer adequate Nutrition in Pregnancy and Lactation
      2. Vegetarian and Vegan diets may be associated with Small for Gestational Age infants
      3. Vegetarians and vegans are less likely to experience Gestational Diabetes, preterm birth and Hypertensive Disorders of Pregnancy
      4. Supplement or increased dietary intake of the following
        1. Dietary Iron or Iron Supplement
        2. Vitamin B12 Supplementation
        3. Zinc
        4. Iodine
        5. Docosahexaeonoic Acid (DHA, omega 3 Fatty Acid supplementation)
      5. Sebastiani (2019) Nutrients 11:557 [PubMed]
      6. Raghavan (2019) Am J Clin Nutr 109:705s [PubMed]
    4. Children and Teens
      1. Vegetarian and Vegan diets offer adequate nutrition in childhood and teen years
      2. Ensure adequate Vegetarian Protein sources (beans, tofu)
      3. Ensure adequate dietary Vitamin intake (iron, zinc, Iodine, Vitamin B12, Calcium, Vitamin D)
      4. Amit (2010) Paediatr Child Health 15:303-14 [PubMed]
    5. Older patients
      1. Ingest Protein sources (e.g. tofu, soy, legumes, nuts, seeds) three times daily
      2. Encourage increased Vitamin B6 intake (e.g. potatoes, bananas, spinach, fotified breakfast cereal)
      3. Ensure adequate Vitamin B12 intake
      4. Omega-3 Fatty Acid Supplementation
      5. Vitamin D Supplementation (and Calcium)

VI. Complications: Vegetarian Diet Related Deficiencies (esp. Vegan)

  1. Macronutrient Deficiency
    1. Protein deficiency
      1. Most Vegetarians and vegans get adequate Protein intake (see above)
  2. Micronutrient Deficiency
    1. Vitamin B12 Deficiency
    2. Zinc Deficiency
    3. Omega 3 Fatty Acid deficiency
    4. Vitamin B2 Deficiency (Riboflavin Deficiency)
    5. Vitamin B3 Deficiency (Niacin Deficiency)
    6. Selenium Deficiency
    7. Iodine Deficiency
      1. Iodine is not found in sea salt or himalayan salt (only added to Iodized Salt)
      2. Other Iodine sources include seafood, seaweed and dairy products
    8. Calcium Deficiency and Vitamin D Deficiency
      1. Osteoporosis Risk

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Vegetarian (finding (C0042441)

Definition (NCI) A person who eats no meat; some may eat fish, eggs, or dairy products.
Concepts Finding (T033)
SnomedCT 300928006
Italian Vegetariano
Japanese 菜食主義者, サイショクシュギシャ
Czech Vegetarián
English vegetarians, vegetarian, Vegetarians, Vegetarian, Vegetarian (finding), Vegetarian (finding
Hungarian Vegetariánus
Spanish vegetariano (hallazgo), vegetariano, Vegetariano
Portuguese Vegetariano
Dutch vegetariër
French Végétarien(ne)
German Vegetarier

Ontology: Vegetarian diet (C0311164)

Definition (MEDLINEPLUS)

A vegetarian diet focuses on plants for food. These include fruits, vegetables, dried beans and peas, grains, seeds and nuts. There is no single type of vegetarian diet. Instead, vegetarian eating patterns usually fall into the following groups:

  • The vegan diet, which excludes all meat and animal products
  • The lacto vegetarian diet, which includes plant foods plus dairy products
  • The lacto-ovo vegetarian diet, which includes both dairy products and eggs

People who follow vegetarian diets can get all the nutrients they need. However, they must be careful to eat a wide variety of foods to meet their nutritional needs. Nutrients vegetarians may need to focus on include protein, iron, calcium, zinc and vitamin B12.

United States Department of Agriculture

Definition (CSP) dietary practice of completely avoiding meat products in the diet.
Definition (MSH) Dietary practice of completely avoiding meat products in their DIET, consuming vegetables, grains, and nuts. Some who are called lacto-ovo also include milk and egg products.
Concepts Therapeutic or Preventive Procedure (T061)
MSH D014676
SnomedCT 80714005, 138044000, 5940000
English Vegetarianism, Vegetarian diet, vegetarian diet, vegetarian diet (history), vegetarian diet (treatment), a vegetarian diet, vegetarian diets, Vegetarianism (finding), Vegetarian, Diet, Vegetarian, Diets, Vegetarian, Vegetarian Diet, Vegetarian Diets, Vegetarian diet - no meat, Vegetarian diet (finding), Vegetarian diet, NOS
Swedish Vegetarianism
Czech dieta vegetářská, dieta vegetariánská, vegetariánství
Finnish Kasvisruokavalio
French Régime alimentaire végétarien, Régime végétarien
Russian DIETA VEGETARIANSKAIA, VEGETARIANSTVO, DIETA RASTITEL'NAIA, ВЕГЕТАРИАНСТВО, ДИЕТА ВЕГЕТАРИАНСКАЯ, ДИЕТА РАСТИТЕЛЬНАЯ
Japanese 菜食主義
Italian Vegetarismo, Dieta vegetariana
Polish Dieta wegetariańska
Croatian Not Translated[Diet, Vegetarian]
Norwegian Vegetarisk kosthold, Vegetarisk kost, Vegetarianisme, Vegetarkost, Vegetarisk diett
Spanish vegetarianismo, vegetarianismo (hallazgo), dieta vegetariana (hallazgo), dieta vegetariana, Dieta Vegetariana, Vegetarianismo
German Vegetarismus, Diät, vegetarische, Vegetarische Diät
Dutch Vegetarisme, Dieet, vegetarisch, Vegetarisch dieet
Portuguese Dieta Vegetariana, Vegetarianismo

Ontology: Lacto-ovo-vegetarian diet (C0311165)

Concepts Therapeutic or Preventive Procedure (T061)
SnomedCT 11152001
English Lacto-ovo-vegetarian diet, Lacto-ovovegetarian diet, Lacto-ovo-vegetarian diet (finding)
Spanish dieta lacto - ovo - vegetariana (hallazgo), dieta lacto - ovo - vegetariana, dieta lactovovegetariana

Ontology: Vegan diet (C0344353)

Definition (NCI) A type of vegetarian diet that excludes all animal products, including dairy, eggs, meat, poultry, fish, and animal fats.
Definition (MSH) Dietary practice of avoiding animal products in their LIFESTYLE.
Concepts Finding (T033)
MSH D014676
SnomedCT 138045004, 162537004, 24930006, 281015005, 267111003
Italian Vegetariano integrale, Dieta vegana
Japanese 完全菜食主義者, カンゼンサイショクシュギシャ
Spanish vegetariano, dietario vegetariano (hallazgo), dietario vegetariano, vegetariano (hallazgo), vegetariano estricto (hallazgo), vegetariano estricto, Vegetariano estricto, Dieta Vegan
Czech dieta veganská, Vegan
French Régime végétalien, Régime alimentaire végétalien, Végétalien(ne)
German Diät, veganische, Veganer, Veganische Diät
English vegan diet (history), vegan diet, a vegan diet, vegan diets, vegans, vegan, diet vegan, Vegan diet, Vegan diet (finding), Diets, Vegan, Vegan Diet, Vegan Diets, Vegan, Strict vegetarian diet, Vegan diet - no dairy produce, Vegan dietary, Vegan dietary habit, Strict vegetarian habit, Vegan (finding), Vegan dietary (finding), Diet, Vegan
Hungarian Vega
Norwegian Vegansk diett, Vegansk kost, Vegansk kosthold
Portuguese Não consumidor de produtos animais, Dieta Vegan
Dutch veganist, Dieet, veganistisch, Veganistisch dieet

Ontology: Vegan (C2987738)

Definition (NCI_NCI-GLOSS) A person who does not eat any foods that come from animals, including meat, eggs, and dairy products. A vegan diet is being studied in the prevention and treatment of prostate cancer and other medical conditions.
Definition (NCI) A person who eats no meat, eggs, or dairy products.
Concepts Population Group (T098)
English Vegan, vegan