Diet

Nutritional Pearls: The Health Risks for Vegetarians

  • Answer: The best diet is the one that works for you and that you can maintain for the long term.

    Today's article shows that even vegetarian or vegan diets can have drawbacks other than needing to eat more carefully to make sure you're getting the right nutrients.

    The Research

    Researchers at Oxford University in the UK made use of information gathered through the EPIC-Oxford Study, which began inviting people to join the study between 1993 and continued recruitment through 2001. Participants were at least 20 years of age at the start of the study and were enrolled both by mail and through their physicians.

    Upon recruitment, participants responded to a questionnaire that asked about diet and lifestyle, health and medical history, and demographic information. A follow-up questionnaire was sent to enrollees in 2010, with the study ending in 2016.

    The authors categorized the participants into meat eaters (those who ate animal protein that included land animal protein), fish eaters (those who did not eat land animal protein but did eat fish or shellfish), vegetarians (lacto-ovo vegetarians), and vegans (those who do not eat animal protein, dairy products, or eggs).

    For their analysis, the researchers excluded those whose questionnaires were incomplete or otherwise unreliable, as well as those who reported a history of heart attack, stroke, or angina prior to the date of recruitment. This left over 48,000 participants.

    Linkage to the UK National Health Service allowed the authors to know which participants had experienced heart disease, heart attack, or stroke (and subtypes of stroke). They then correlated the participants' diets with the reported health events.

    The Results

    After taking into account variables such as history of high blood pressure, poor cholesterol scores, smoking status, age and gender, physical activity, diabetes status, and body mass index, the researchers found that vegetarians/vegans (the 2 were analyzed together due to the small number of vegans) had a lower risk of heart attack and heart disease than those who ate land animal protein.

    No surprise there.

    However, compared to those who consumed land animal protein, lacto-ovo vegetarians and vegans were 20% more likely to have a stroke of any kind—and 43% more likely to have a hemorrhagic stroke.

    What’s the Take Home?

    Those in this study who did not eat land animal protein had lower circulating levels of B12, vitamin D, certain amino acids, and omega-3 fatty acids, but had slightly lower BMI and better cholesterol and blood pressure scores, which may partially explain the difference in risk of heart attack versus stroke.

    This suggests that question of which is the "best" or "healthiest" diet are more nuanced than some people would like you to think: as a primary care physician, I believe that the best diet, whether omnivore, pesceterian, lacto-ovo vegetarian, or vegan, is the one that works for you and that you can maintain for the long term.

    Reference:

    Tong TYN, Appleby PN, Bradbury KE, et al. Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up: results from the prospective EPIC-Oxford study. BMJ 2019;366:l4897.