Plant-based diets and long-term health: findings from the EPIC-Oxford study

Abstract

The concept of plant-based diets has become popular due to the purported benefits for both human health and environmental impact. Although 'plant-based' is sometimes used to indicate omnivorous diets with a relatively small component of animal foods, here we take it to mean either vegetarian (plant-based plus dairy products and/or eggs) or vegan (100% plant-based). Important characteristics of plant-based diets which would be expected to be beneficial for long-term health are low intakes of saturated fat and high intakes of dietary fibre, whereas potentially deleterious characteristics are the risk of low intakes of some micronutrients such as vitamin B₁₂, vitamin D, calcium and iodine, particularly in vegans. Vegetarians and vegans typically have lower BMI, serum LDL cholesterol and blood pressure than comparable regular meat-eaters, as well as lower bone mineral density. Vegetarians in the EPIC-Oxford study have a relatively low risk of IHD, diabetes, diverticular disease, kidney stones, cataracts and possibly some cancers, but a relatively high risk of stroke (principally haemorrhagic stroke) and bone fractures, in comparison with meat-eaters. Vegans in EPIC-Oxford have a lower risk of diabetes, diverticular disease and cataracts and a higher risk of fractures, but there are insufficient data for other conditions to draw conclusions. Overall, the health of people following plant-based diets appears to be generally good, with advantages but also some risks, and the extent to which the risks may be mitigated by optimal food choices, fortification and supplementation is not yet known.

Keywords: Cancer; Cardiovascular; Plant-based; Vegan; Vegetarian.

Fig. 1. Risk of various conditions in vegetarians compared with meat eaters in the EPIC-Oxford study

* Includes data from EPIC-Oxford and the Oxford Vegetarian Study combined. †Adjusted for body mass index (BMI). ‡Vegetarians and vegans combined. The hazard ratios and 95% confidence intervals (CIs) presented are in reference to the following groups: regular meat eaters who consume 50+ grams of meat per day (diabetes); high meat eaters who consumed 100+ grams of meat per day (kidney stones and cataracts); meat eaters (ischaemic heart disease, total and haemorrhagic stroke, all cancers and subtypes, all fractures and hip fractures, diverticular disease); non-vegetarians who eat meat or fish (gallstones).

Fig. 2. Risk of various conditions in vegans compared with meat eaters in the EPIC-Oxford study

* Includes data from EPIC-Oxford and the Oxford Vegetarian Study combined. †Adjusted for body mass index (BMI). The hazard ratios and 95% confidence intervals (CIs) presented are in reference to the following groups: regular meat eaters who consume 50+ grams of meat per day (diabetes); high meat eaters who consumed 100+ grams of meat per day (cataracts); meat eaters (all cancers, all fractures and hip fractures, diverticular disease).