Cancer is the leading cause of death globally. In the UK, a significant 28% of all deaths in 2017 were attributable to cancer, with colorectal, breast, and prostate cancer collectively making up 39% of all new cancer diagnoses.
It has been suggested that vegetarian diets, which omit consumption of all meat and fish, may be associated with a lower cancer risk.
Low meat-eaters (people wo consume less meat five times per week or less) and pescatarians (those who eat fish, but not meat), may also benefit from a lower cancer risk.
Researchers in the UK have sought to find out.
A lower risk of all cancer
The team, made up of researchers from Oxford University, aimed to identify associations of vegetarian and non-vegetarian diets with risks of all cancer, colorectal cancer, postmenopausal breast cancer, and prostate cancer.
A prospective analysis of 472,377 UK Biobank participants were recruited. They were categorised into four dietary groups: regular meat-eaters, low meat-eaters, fish-eaters, and vegetarians, based on responses to dietary questions.
After an average follow-up of 11.4 years, 54,961 incidences of cancer in the previously cancer-free participants were identified. These included 5,882 colorectal, 7,537 postmenopausal breast, and 9,501 prostate cancers.
Findings revealed that being a low-meat eater, fish-eater, or vegetarian were all associated with a lower risk of all cancer.
Being a low meat-eater was associated with a lower risk of colorectal cancer in comparison to regular meat-eaters.
And vegetarian postmenopausal women had a lower risk of breast cancer. In mediation analyses, BMI was found to possibly mediate the observed association.
In men, being a fish-eater or a vegetarian was associated with a lower risk of prostate cancer.
More research required
To put these findings into numbers, vegetarians had a 14% lower risk of all cancers than people who eat meat more than five times a week. For fish-eaters, it was 10% lower, and for low meat-eaters, 2% lower.
The differences observed between diet groups for all cancer outcomes combined, however, may not be due to diet, the researchers noted. Rather, they might be due to ‘residual confounding’ by differences in other lifestyle factors, such as smoking.
“Further research assessing cancer risk in cohorts with large numbers of vegetarians is needed to provide more precise estimates of the associations and to explore other possible mechanisms or explanations for the observed differences,” the study authors added.
Source: BMC Medicine
‘Risk of cancer in regular and low meat-eaters, fish-eaters, and vegetarians: a prospective analysis of UK Biobank participants’
Published 24 February 2022
Authors: Cody Z. Watling, Julie A. Schmidt, Yashvee Dunneram, Tammy Y. N. Tong, Rebecca K. Kelly, Anika Knuppel, Ruth C. Traves, Timothy J. Key and Aurora Perez-Cornago.