Vegetarian Nutrition

Vegetarian Nutrition

Welcome to the Vegetarian Nutrition Disease Prevention Project

Lifestyle behaviors, including dietary patterns, play an important role in the prevention of cardiovascular and other diseases. Several observational studies have suggested that those following vegetarian, including vegan, dietary patterns may have a lower risk of certain diseases. A vegetarian dietary pattern is one that does not include intake of flesh products such as meat, poultry or fish, and a vegan diet additionally does not include other animal products such as dairy products or eggs. Understanding the benefits and harms of vegetarian and vegan diets for presumably healthy adults in the general population can help inform nutrition practitioners working with adult clients who follow or are interested in following vegetarian or vegan diets. 

There are several current systematic reviews that report on the impact of vegetarian diets compared to non-vegetarian diets on a range of outcomes. Therefore, the EAL team conducted an overview of systematic reviews, also called an umbrella review, to answer the research question: In presumably healthy adults in the general population, what are the relationships between vegetarian, including vegan, diets compared to non-vegetarian diets in:

  • Health Outcomes: incidence of cardiovascular disease, type 2 diabetes, cancer, bone fractures and cardiovascular events; 
  • Nutrient Status: concentrations of vitamin B12, calcium, hemoglobin, ferritin, iodine, vitamin D, omega-3s, BMI, bone density, muscle mass/lean body mass, fat mass; and
  • Other Biomarkers: blood pressure and concentrations of LDL-cholesterol, triglycerides, and c-reactive protein. 

Key findings:

  • This umbrella review analyzed and summarized findings from 27 systematic reviews published from 2018 to January 2023. Evidence describing relationships between vegetarian diets and outcomes for adults in the general population was primarily observational. 
  • Moderate certainty of evidence describes vegetarian diets, including vegan diets, reduced cardiovascular disease incidence compared to non-vegetarian diets. 
  • Low and very low certainty of evidence described several other potential benefits of following a vegetarian and/or vegan diet, including reduced risk of cardiovascular disease mortality, reduced blood pressure, blood lipids, BMI and c-reactive protein concentrations. 
  • However, low and very low certainty evidence also described some potential harms of following vegetarian diets for adults in the general population, including lower bone mineral density, and increased risk of fractures and lower vitamin B12 and vitamin D concentrations for those following vegan diets.  

Use the left navigation bar to view the results of the umbrella review. Expand the section below titled Umbrella Review Project Team and Disclosures for a listing of individuals who contributed their time and expertise to the development of this project, conflict of interest disclosures, and project funding information. 

Note: The expert panel is finalizing an umbrella review on vegetarian nutrition and disease management. The results will be published in January 2024.  

  • Umbrella Review Project Team and Disclosures (2023)

    The following individuals contributed their valuable time and expertise to this project:

    Expert Panel Members

    • Sudha Raj, PhD, RDN, FAND, Chair 
      Department of Nutrition and Food Studies, Syracuse University, Syracuse, NY, USA
    • Matthew Landry, PhD, RDN, LDN 
      Standford University School of Medicine, Palo Alto, CA, USA
    • Nanci Guest, PhD, RD, CSCS 
      Private Practice, Toronto, ON, Canda
    • Reed Mangels, PhD, RDN, FADA 
      Department of Nutrition, University of Massachusetts Amherst, Amherst, NY, USA
    • Roman Pawlak, PhD, RD 
      Department of Nutrition Science, East Carolina University, Greenville, NC, USA
    • Winston Craig, PhD, MPH 
      Retired, Walla Walla, WA, USA

    Project Team

    • Mary Rozga, PhD, RND, Project Manager and Methodologist
      Nutrition Researcher, Academy of Nutrition and Dietetics, Chicago, IL, USA
    • Katelyn Senkus, MS, RDN, Lead Analyst
      Universityof Alabama, Tuscaloosa, AL, USA
    • Amanda Wanner, MLS, AHIP, Information Specialist
      Consultant, Saint John, NB, Canada

    Evidence Analysts

    • Kathy S. Keim, PhD, RDN, Chicago, IL, USA
    • Keiy Murofushi, MS, RD, Los Angeles, CA, USA

    Financial Contributors

    • Vegetarian Nutrition Dietetic Practice Group
    • Academy of Nutrition and Dietetics Foundation
    • Academy of Nutrition and Dietetics

    The views and interests of the funding bodies did not influence the development of the umbrella review.

    Disclosures of Potential Conflicts of Interests

    In the interest of full disclosure, the Academy has adopted the policy of revealing relationships expert panel members have with companies that sell products or services that are relevant to this topic. Expert panel members are required to disclose potential conflicts of interest by completing the Academy Conflict of Interest Form. It should not be assumed that these financial interests will have an adverse impact on the content, but they are noted here to fully inform readers.

    • None of the expert panel members listed above disclosed potential conflicts of interest.