Vegetarian Nutrition

VN: Executive Summary of Recommendations (2011)

Executive Summary of Recommendations

Below are the major recommendations and ratings for the Academy of Nutrition and Dietetics Vegetarian Nutrition (VN) Evidence-Based Nutrition Practice Guideline.  More detail (including the evidence analysis supporting these recommendations) is available on this website to Academy members and EAL subscribers under Major Recommendations.

To see a description of the Academy Recommendation Rating Scheme (Strong, Fair, Weak, Consensus, Insufficient Evidence), click here.

The Vegetarian Nutrition Recommendations are listed below. (Note: If you mouseover underlined acronyms and terms, a definition will pop-up.)

  • Nutrition Assessment
    VN: Assessing Knowledge and Beliefs of Adult, Child and Adolescent Vegetarians
    For adult, child and adolescent vegetarians, the Registered Dietitian (RD) should assess knowledge and beliefs about a vegetarian diet. Research indicates that vegetarian dietary patterns vary and fluctuate over time. Even within types of vegetarian diets, individuals may not always include a variety of healthful foods in their diet. Vegetarians who are on highly restrictive diets resulting from unhealthful food choices, may be at nutritional risk. Specific nutrient considerations may need to be addressed in some vegetarian dietary patterns for optimal nutrition. 
    Strong
    Imperative
    VN: Assessing Motivations that Influence Vegetarian Dietary Lifestyle for Adults and Children
    For adult, child and adolescent vegetarians, the Registered Dietitian (RD) should assess reasons for following a vegetarian lifestyle. Research indicates that the motivations for being vegetarian (e.g., health, ethical, environmental, cultural or religious, etc.) influence dietary practices which may impact nutrient intake. Dietary patterns based on health beliefs may be more flexible than dietary patterns based on religious or moral convictions. 
     
    Strong
    Imperative
    VN: Assessing for Signs of Disordered Eating Behaviors Among Adolescent and Young Adult Vegetarians
    In adolescent (13-18) and young adult (19 to 30 years) vegetarians, the Registered Dietitian (RD) should assess for problem behaviors such as dieting. Research finds that a subset of vegetarian adolescents and young adults shows higher patterns of unhealthful dieting practices than omnivores or more health conscious vegetarians of the same age. 
    Fair
    Imperative
    VN: Assessing Micronutrient Needs in Pregnant Adolescent and Adult Vegetarians
    For pregnant adolescent and adult vegetarians, the Registered Dietitian (RD) should assess the patient's/client's intake of all micronutrients, particularly folate, vitamin B-12, iron, and zinc to ensure the Dietary Reference Intakes (DRI) are met. Research indicates that pregnant vegetarians did not meet dietary requirements for at least one of these micronutrients. Two high quality studies report that pregnant vegetarians had significantly lower serum B-12 concentrations than pregnant non-vegetarians. In addition, research studies measuring methylmalonic acid (MMA) levels, showed that the prevalence of vitamin B-12 deficiency among healthy, non-pregnant adult vegetarians ranged from 30% to 86%. When vegans and lacto-ovo vegetarians/lacto-vegetarians (LOV/LV) were analyzed separately, vegans had even higher proportions of vitamin B-12 deficiency (43% to 88%).
    Strong
    Conditional
    VN: Assessing Macronutrient Needs in Pregnant Adolescent and Adult Vegetarians
    For pregnant adolescent and adult vegetarians and vegans, the Registered Dietitian (RD) should assess for adequate protein from a variety of complementary mixtures of plant proteins consumed throughout the day, compared to the Dietary Reference Intakes (DRI) in pregnancy. While research indicates that pregnant vegetarians typically had lower protein intake than pregnant omnivores, they met or exceeded the national standards for protein intake for pregnant women in the populations studied.    
    Strong
    Imperative
    VN: Assessing Essential Fatty Acid Intake of Pregnant Adolescent and Adult Vegetarians
    For pregnant adolescent and adult vegetarians, the Registered Dietitian (RD) should assess dietary intake of essential fatty acids (EFA). Some research suggests that blood and tissue eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels may be sub-optimal among patients who follow a vegetarian dietary pattern.
     
    Consensus
    Imperative
    VN: Assessing Biochemical Data of Adult, Child and Adolescent Vegetarians
    For adult, child and adolescent vegetarians for whom dietary assessment reveals inadequate intake, the Registered Dietitian (RD) should assess the biochemical data, medical tests and procedures including, but not limited to complete blood count (CBC), serum iron, ferritin, transferrin, vitamin B-12, zinc, vitamin D and essential fatty acids (EFA). Research suggests that intake and/or bioavailability of these nutrients may be of special concern for vegetarian or vegan adults, adolescents and children. Assessment of these factors is needed to effectively determine nutrition diagnoses and plan the nutrition interventions. Inability to achieve optimal nutrient intake may contribute to poor outcomes. 
    Consensus
    Imperative
    VN: Assessing Vitamin B-12 Status of Adult, Child and Adolescent Vegetarians
    For adult, child and adolescent vegetarians, the Registered Dietitian (RD) should assess for dietary adequacy of vitamin B-12 intake.  If dietary intake of vitamin B-12 is inadequate, then the RD may recommend using methylmalonic acid (MMA) if available, as a functional indicator of deficiency. Two research studies measuring MMA levels showed that lacto-ovo vegetarian and lacto-vegetarian (LOV/LV) or omnivorous adolescents (9 to 15 years) who had followed a very restrictive vegetarian diet (macrobiotic) early in life, may be at risk for vitamin B-12 deficiency (41% of adolescents had MMA >290nmol/L and 21% had MMA >410nmol/L). In addition, research studies showed that the prevalence of vitamin B-12 deficiency among healthy, non-pregnant adult vegetarians ranged from 30% to 86%. When vegans and LOV/LV vegetarians were analyzed separately, vegans had even higher proportions of vitamin B-12 deficiency (43% to 88%). Among children (10 months to 11.7 years) and older adults (>55 years), the prevalence of vitamin B-12 deficiency was 55 to 85% and 46.9% to 68%, respectively. 
    Fair
    Imperative
    VN: Assessing Micronutrient Intake of Adolescent Vegetarians
    For adolescent vegetarians, the Registered Dietitian (RD) should assess micronutrient intake, particularly iron, zinc, vitamin C and vitamin B-12. Research from a limited number of Western countries indicates that adolescent vegetarians or semi-vegetarians (11 to 19 years) may have lower intake than national standards for micronutrients such as iron, zinc and vitamin C. In addition, two studies measuring methylmalonic acid (MMA) levels showed that lacto-ovo vegetarian/lacto-vegetarian (LOV/LV) or omnivorous adolescents (9 to 15 years) who had followed a very restrictive vegetarian diet (macrobiotic) early in life, may be at risk for vitamin B-12 deficiency (41% of adolescents had MMA >290nmol/L and 21% had MMA >410nmol/L).
    Strong
    Imperative
    VN: Assessing Dietary Intake of Adolescent Vegetarians
    For adolescent vegetarians, the Registered Dietitian (RD) should assess intake of foods rich in calcium (e.g., dairy products, kale, broccoli, fortified soy milk, etc.). Research indicates that although dietary patterns differ among countries, adolescent vegetarians (11 to 19 years) tended to consume fewer dairy products.
    Strong
    Imperative
    VN: Assessing Micronutrient Intake of Vegetarian Children
    For vegetarian children, the Registered Dietitian (RD) should assess micronutrient intake, particularly vitamin B-12. Research studies measuring methylmalonic acid (MMA) levels, indicate that small children (10 months to 11.7 years) of parents who follow a macrobiotic diet, had a high prevalence of vitamin B-12 deficiency (55 to 85%).
    Weak
    Imperative
    VN: Assessing Macronutrient Intake of Child and Adolescent Vegetarians
    For child and adolescent vegetarians, the Registered Dietitian (RD) should assess intake of protein and essential fatty acids (EFA). While meeting protein requirements is typically not an issue with vegetarian diets, the RD can recommend that children and adolescents include complementary mixtures of plant proteins. This can be achieved by consuming a varied diet throughout the day. In addition, some research suggests that blood and tissue eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels may be sub-optimal among patients who follow a vegetarian dietary pattern.
     
    Consensus
    Imperative
    VN: Assessing Micronutrient Intake of Adult Vegetarians
    For adult vegetarians, the Registered Dietitian (RD) should assess micronutrient intake, particularly vitamin B-12. Research studies measuring methylmalonic acid (MMA) levels, showed that the prevalence of vitamin B-12 deficiency among healthy, non-pregnant adult vegetarians ranged from 30% to 86%. When vegans, lacto-ovo vegetarians/lacto-vegetarians (LOV/LV) were analyzed separately, vegans had even higher proportions of vitamin B-12 deficiency (43% to 88%). Among older adults (>55 years), the prevalence of vitamin B-12 deficiency was 46.9% to 68%.  
    Fair
    Imperative
    VN: Assessing Protein Intake of Adult Vegetarians
    For adult vegetarians, the Registered Dietitian (RD) should assess intake of protein. While meeting protein requirements is typically not an issue with vegetarian diets, the RD can recommend that adults include complementary mixtures of plant proteins. This can be achieved by consuming a varied diet throughout the day. 
    Consensus
    Imperative
    VN: Assessing Essential Fatty Acid Intake of Adult Vegetarians
    For adult vegetarians, the Registered Dietitian (RD) should assess dietary intake of essential fatty acids (EFA). Some research suggests that blood and tissue eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels may be sub-optimal among patients who follow a vegetarian dietary pattern.
    Consensus
    Imperative
  • Nutrition Intervention
    VN: Treating Hyperlipidemia with a Vegetarian Diet for Adults
    If consistent with patient or client preference, the Registered Dietitian (RD) may recommend and educate on the benefits of a vegetarian diet for adults seeking treatment to lower total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels, or if appropriate, to reduce weight. Research shows that various types of vegetarian diets (e.g., vegetarian Ornish, Portfolio diet, ovo-lacto vegetarian and vegan) lower TC from 7.2% to 26.6% and lower LDL-C from 8.7% to 35% (with five of the eight studies that provided comparison data showing a decrease between 10% and 20% for both TC and LDL-C). Vegan diets lower both TC and LDL-C more than other types of vegetarian diets. 
    Strong
    Conditional
    VN: Micronutrient Intake in Pregnant Adolescent and Adult Vegetarians
    For pregnant adolescent and adult vegetarians, the Registered Dietitian (RD) should design a nutrition prescription to ensure the Dietary Reference Intakes (DRI) for all micronutrients are met. If unable to meet the DRI for recommended levels of micronutrients, particularly iron, folate and zinc, the RD should recommend supplementation to ensure adequate intake. Research indicates that pregnant vegetarians did not meet dietary requirements for at least one of these micronutrients.  
    Fair
    Conditional
    VN: Vitamin B-12 Intake in Pregnant Adolescent and Adult Vegetarians
    For pregnant adolescent and adult vegetarian or vegan patients or clients, the Registered Dietitian (RD) should design a nutrition prescription to ensure vitamin B-12 requirements are met by diet and/or supplementation, including prenatal supplements. Two high quality studies report that lacto-ovo vegetarian pregnant women are less likely than non-vegetarian pregnant women to meet dietary requirements for vitamin B-12 intake, and two high quality studies report that pregnant vegetarians had significantly lower serum B-12 concentrations than pregnant non-vegetarians. In addition, twelve studies measuring methylmalonic acid (MMA) levels, showed that the prevalence of vitamin B-12 deficiency among healthy, non-pregnant adult vegetarians ranged from 30% to 86%. When vegans and lacto-ovo vegetarians/lacto-vegetarians (LOV/LV) were analyzed separately, vegans had even higher proportions of vitamin B-12 deficiency (43% to 88%).
    Fair
    Imperative
    VN: Nutrition Counseling to Support Therapeutic Vegetarian Diets for Adults
    If a vegetarian diet is proposed as a therapeutic diet according to stage in the life cycle and disease state for adults, the Registered Dietitian (RD) should employ a a variety of counseling approaches and strategies to promote adherence to the diet. Research shows that intensive support (e.g., frequent encounters, cooking demonstration, incentives, etc.) can improve nutrition-related outcomes when using a vegetarian diet therapeutically; and nutrition counseling strategies such as motivational interviewing, can improve adherence to recommendations and diet-related outcomes.
    Strong
    Conditional
    VN: Diet Diversity of Vegetarian Diets for Children, Adolescents and Adults
    If the adult, child or adolescent patient or client is on a highly restrictive vegetarian diet with a narrow range of food choices, then the Registered Dietitian (RD) should educate them on the importance of including a variety of foods within their diet to meet their nutritional needs. When appropriate, vitamin and/or mineral supplements may be indicated. Research shows that vegetarian dietary patterns vary and fluctuate over time. Even within types of vegetarian diets, individuals vary in the extent to which they include a variety of plant-based foods. Vegetarians who are on highly restrictive diets resulting from unhealthful food choices, may be at nutritional risk.
    Strong
    Conditional
    VN: Protein Intake of Pregnant Adolescent and Adult Vegetarians
    For pregnant adult and adolescent vegetarians and vegans, the Registered Dietitian (RD) should develop a nutrition prescription and offer comprehensive nutrition education and skill development on planning a diet which provides adequate protein from a variety of complementary mixtures of plant proteins consumed throughout the day. While research indicates that pregnant vegetarians typically had lower protein intake than pregnant omnivores, they met or exceeded the national standards for protein intake for pregnant women in the populations studied.   
    Weak
    Imperative
    VN: Essential Fatty Acid Intake of Pregnant Adolescent and Adult Vegetarians
    For the pregnant adolescent or adult vegetarian, if nutrition assessment of intake or blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reveals a potential deficiency or lower than optimal levels, the Registered Dietitian (RD) should counsel the patient or client to increase EPA and DHA levels by any of the following methods (as appropriate based on RD clinical judgment):
    • Increasing intake of foods rich in EPA and DHA
    • EPA and DHA supplementation
    • Increase endogenous synthesis of essential fatty acids (EFA) by decreasing intake of omega-6 fatty acid as well as reducing the amount of saturated fat  and trans fat in the diet.
    Consensus
    Conditional
    VN: Treating Type 2 Diabetes with a Vegetarian Diet for Adults
    If consistent with patient or client preference, the Registered Dietitian (RD) may recommend and educate on the benefits of the therapeutic use of a vegetarian diet for adults seeking treatment for Type 2 diabetes. Research indicates that a vegetarian diet may decrease or maintain blood glucose levels; a vegan diet may decrease hemoglobin A1c (A1c), as well as, or better than an omnivorous diet. Additionally, a vegetarian diet may reduce diabetes-related co-morbidities (e.g., cardiovascular disease, obesity, and hypertension).
    Fair
    Conditional
    VN: Treating Overweight and Obesity with a Vegetarian Diet for Adults
    If consistent with patient or client preference, the Registered Dietitian (RD) may recommend and educate on the benefits of the therapeutic use of a vegetarian diet for adults seeking treatment for overweight or obesity. Research indicates that the therapeutic use of a vegetarian diet is effective for treating overweight and obesity in both the short term (less than one year) and longer term (greater than one year), and may perform better than alternative omnivorous diets for the same purpose. Percent weight loss ranged from 3.2% to 9.3% at 12 months across studies.
    Strong
    Conditional
    VN: Micronutrient Intake of Adolescent Vegetarians
    For adolescent vegetarians, the Registered Dietitian (RD) should specifically plan foods rich in micronutrients, such as iron, zinc, vitamin C and vitamin B-12 into the diet to meet the Dietary Reference Intakes (DRI). When appropriate, vitamin and/or mineral supplements may be indicated to prevent or resolve nutrient deficiency. Research from a limited number of Western countries showed that adolescent vegetarians or semi-vegetarians (11 to 19 years) may have lower intake than national standards for micronutrients such as iron, zinc and vitamin C. In addition, two studies measuring methylmalonic acid (MMA) levels showed that lacto-ovo vegetarian and lacto-vegetarian (LOV/LV) or omnivorous adolescents (9 to 15 years) who had followed a very restrictive vegetarian diet (macrobiotic) early in life, may be at risk for vitamin B-12 deficiency (41% of adolescents had MMA >290nmol/L and 21% had MMA >410nmol/L).
    Fair
    Imperative
    VN: Dietary Intake of Adolescent Vegetarians
    For adolescent vegetarians, the Registered Dietitian (RD) should recommend a meal plan that incorporates foods rich in calcium (e.g., dairy products, kale, broccoli, fortified soy milk, etc.) or if appropriate, calcium supplements. Research indicates that although dietary patterns differ, adolescent vegetarians (11 to 19 years) tended to consume fewer dairy products.
    Strong
    Imperative
    VN: Micronutrient Intake of Vegetarian Children
    For vegetarian children, the Registered Dietitian (RD) should design a nutrition prescription to ensure the Dietary Reference Intakes (DRI) for all micronutrients, particularly vitamin B-12 are met. If appropriate, vitamin and/or mineral supplements may be needed to prevent or resolve nutrient deficiency. Research studies measuring methylmalonic acid (MMA) levels, indicates that small children (10 months to 11.7 years) of parents who follow a macrobiotic diet, had a high prevalence of vitamin B-12 deficiency (55 to 85%). 
    Weak
    Imperative
    VN: Micronutrient Intake of Adult Vegetarians
    For adult vegetarian patients or clients, the Registered Dietitian (RD) should design a nutrition prescription to ensure the Dietary Reference Intakes (DRI) for all micronutrients, particularly vitamin B-12 are met. When appropriate, vitamin and/or mineral supplements may be indicated to prevent or resolve nutrient deficiency. Research studies measuring methylmalonic acid (MMA) levels showed that the prevalence of B-12 deficiency among healthy, non-pregnant adult vegetarians ranged from 30% to 86%. When vegans and lacto-ovo vegetarians/lacto-vegetarians (LOV/LV) were analyzed separately, vegans had even higher proportions of vitamin B-12 deficiency (43% to 88%). Among older adults (>55 years), the prevalence of vitamin B-12 deficiency was 46.9% to 68%.
    Fair
    Imperative
    Vegetarian Nutrition (VN) Protein Intake of Adult, Child and Adolescent Vegetarians
    For adult, child and adolescent vegetarians, the Registered Dietitian (RD) should develop a nutrition prescription providing adequate protein, and offer comprehensive nutrition education and skill development on planning a diet which provides a variety of protein foods. While meeting protein requirements is typically not an issue with vegetarian diets, the RD can recommend including complementary mixtures of plant proteins. This can be achieved by consuming a varied diet throughout the day.  
    Consensus
    Imperative
    VN: Essential Fatty Acid Intake of Adult, Child and Adolescent Vegetarians
    In the adult, child or adolescent vegetarian, if nutrition assessment of intake or blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reveals a potential deficiency or lower than optimal levels, the Registered Dietitian (RD) should counsel the patient or client to increase EPA and DHA levels by any of the following methods (as appropriate based on RD clinical judgement):
    • Increasing intake of foods rich in EPA and DHA
    • EPA and DHA supplementation
    • Increase endogenous synthesis of essential fatty acids (EFA) by decreasing intake of omega-6 fatty acid as well as reducing the amount of saturated fat and trans fat in the diet.
    Consensus
    Conditional
  • Nutrition Monitoring and Evaluation
    VN: Adherence to a Vegetarian Therapeutic Diet for Adults
    For adult patients or clients, the Registered Dietitian (RD) should monitor and evaluate adherence to a therapeutic vegetarian diet. Research indicates that these diets appear to perform as well and possibly better than omnivorous diets in terms of attrition rate, provided that patients receive nutrition education and appropriate dietary support. Many factors may influence the adherence to a diet, such as disease state, length of intervention, restrictiveness, and patient support.
    Strong
    Imperative
    VN: Adherence to Vegetarian Diets for Treatment of Obesity and Overweight for Adults
    For adult patients or clients seeking treatment for overweight or obesity with a vegetarian diet, the Registered Dietitian (RD) should monitor and evaluate adherence and provide continued nutrition education support. Research shows lower compliance rates for weight loss patients vs. patients treated for other disease states.
    Strong
    Imperative