Vegan Society response to Cancer in Vegetarians and Vegans study, published in British Journal of Cancer
By Claire Ogley, Head of Campaigns, Policy and Research at The Vegan Society:
“The Vegan Society welcomes many of the findings of the largest ever study of non-meat diets and cancer risk, published today in the British Journal of Cancer.
The conclusion of the meta-study found that: ‘To increase your overall protection from cancer, our advice is to build meals around wholegrains, pulses, fruit and vegetables, and avoid processed meat and limit red meat.’
The Vegan Society endorses this advice. As the British Dietetic Association affirms, well planned plant-based diets, including vegan diets, can provide all the nutrition people need across all life stages, to support healthy living and reduce the risk of some non-communicable diseases, such as cardiovascular disease and type II diabetes.
As the study’s authors clearly state, the finding that vegans have an apparently increased risk of colorectal (bowel) cancer compared to meat eaters must be interpreted with caution. The vegan sample size was small and because this is a long-term study where most vegan participants were recruited decades ago, diets followed by vegans today may have significantly different nutritional profiles. In particular, the study identified lower calcium levels among vegans historically and speculates that this may be a contributory factor. However, calcium is readily available from a wide variety of plant foods and from fortified products such as plant milks. Recent evidence indicates that average calcium levels among vegans are now equivalent to those among the general population and meet recommended levels.
Vegans should not feel pressured to change their diet based on these early findings, as there are significant limitations in the research. We encourage vegans to follow a well-planned diet rich in fruits, vegetables, pulses, wholegrains, nuts and seeds, with appropriate supplementation. These foods are consistently shown to support good health and reduce the risk of several cancers.
Should people wish to consider supplementation, The Vegan Society offers a product called VEG 1, designed to complement a balanced vegan diet by providing key nutrients without the use of animal products.”
Notes
- The ‘Vegetarian diets and cancer risk’ meta-study found that, compared with meat eaters, vegetarians had a lower risk of breast, kidney, pancreatic and prostate cancers, in addition to lower risk of multiple myeloma.
- Taken out of methodological context, the survey’s observation of a higher risk of colorectal (bowel) cancer in vegans, when compared with meat eaters, might cause concern for vegans or people following a plant-based diet.
It should be stressed that the observation is based on only 93 incident cases among vegans in seven studies in the UK and US, from 8849 vegans surveyed in an overall sample size of 1.8m people. There is no suggestion of increased overall cancer risk for vegans.
- The meta-study’s methodology is complicated and vegans comprised only 0.5 percent of its participants. The study states: “for vegans ... numbers of cases [of cancer] and therefore statistical power were low.”
- Subjects were surveyed over a median of 16 years, with 82 percent of the vegans in this meta-analysis drawn from studies (AHS-2 and EPIC-Oxford) conducted in the early 2000s, when dietary habits, including supplementation, were very different to those in 2026.
- Participants were grouped according to their diet during the 12 months prior to the start of the study, meaning a person classified as vegan (or any other dietary group) at baseline may have consumed meat for much of their earlier life and only changed their diet a year before study commencement. Biological risk profile may still reflect decades of meat consumption, yet analytically they are treated as lifelong vegans.
As cancer often has a long latency period, developing over many decades, this exposure misclassification may negatively affect resulting associations. Colorectal cancer in vegans is not even nominally statistically significant when the first four years of follow-up is excluded.
- Median calcium intake by vegans in the study was 590mg per day, which is less than the 700mg currently recommended in the UK. However, a 2021 systematic review found that calcium levels in vegans are now above the recommended level and only slightly below those of average meat eaters: 'Across all studies, average calcium intake was slightly higher in vegetarians (895 mg/d) than in vegans (838 mg/d) or meat-eaters (858 mg/d)’. There is no evidence to confirm why this is the case but supplementation may be an important factor.
Generally, as the scientists behind this study readily acknowledge, “for some less common cancers there were too few vegan cases to analyse. Further studies are needed to confirm these results in the vegan population.”
As the study’s conclusion states: ‘The generalisability should be considered cautiously.’
With vegan numbers having grown so much in recent years, The Vegan Society looks forward to further reports on the impact of a plant-based diet on general health.
