Reduced Cancer Risk: Insights from a Meta-Analysis of Vegan and Vegetarian Diets

A comprehensive analysis of available research found that following a vegan diet appears to significantly lower the risk of heart disease and some types of cancer.

The analysis summarized 98 studies involving over 130,000 vegetarians and 15,000 vegans. It compared diets completely free of animal products (vegan) or with no meat or fish (vegetarian) to non-vegetarian omnivorous diets.

Key findings for a vegan diet:

15% lower risk of developing any type of cancer

Lower BMI, cholesterol, LDL cholesterol, and blood sugar levels compared to non-vegans

Key findings for a vegetarian diet:

25% lower risk of dying from heart disease

8% lower risk of developing any type of cancer

Lower BMI by 1.5 units on average, 28 points lower cholesterol, 21 points lower LDL cholesterol and over 5 points lower blood sugar levels compared to non-vegetarians

The reasons for the lower heart disease and cancer risk appear to be linked to lower intakes of saturated fat and higher consumption of protective foods like vegetables, fruits, whole grains, nuts and soy foods in the vegetarian and vegan diets.

The researchers concluded that significant evidence exists that vegetarian and especially vegan diets may provide safety advantages compared to non-vegetarian diets. But more research is still needed, especially on different health outcomes of vegan diets specifically.

So vegetarians and vegans may expect noticeable benefits versus meat eaters when it comes to risk for major chronic diseases, if the results represent true cause-and-effect relationships. Those considering switching to a vegan diet can be cautiously reassured by these findings.

Dinu M, Abbate R, Gensini GF, Casini A, Sofi F. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Crit Rev Food Sci Nutr. 2017 Nov 22;57(17):3640-3649. PMID: 26853923 DOI: 10.1080/10408398.2016.1138447