An examination of previous dietary studies has concluded that vegetarian diets “undoubtedly” decrease the risk of certain cancer types.
Published in the BMC Medicine journal, Mathias Weller’s analysis examines findings from multiple previous research projects. All demonstrate that meat reduction has a positive impact on personal health with regard to cancer rates. Such findings led the European Parliament to promote plant-based diets as a weapon against cancer, earlier this year.
Vegetarian and pescatarian diets retain the spotlight throughout the scrutinized studies. Research also suggests that cancer risk is lower in vegans, though this is not expanded on in the analysis.
Weller’s analysis specifically offers insight into discrepancies between research findings. It also supports the general acknowledgment that eating less meat is a health-forward choice.
Vegetarian diets and cancer
Small studies cited in Weller’s commentary suggested that vegetarians are less likely to contract gastrointestinal tract cancer than meat-eaters. Stomach, lymphatic, and blood-based cancers are also less likely. Both vegetarians and pescatarians showed a reduced risk of contracting colorectal cancer.
Two large studies used data collected from 409,110 and 472,377 UK participants respectively. Again, both found vegetarian diets incurred a lower risk of all cancers.
The two studies took different approaches, yet reached similar conclusions. One, conducted by Oxford University, broke participants down into “regular” and “low” meat consumption, “pescatarian,” and “vegetarian.” Meanwhile, the other split respondents into “meat,” “fish-poultry,” and “vegetarian” models.
Overall, both found that a reduction in meat correlates to a reduced risk of cancer, with Oxford University reporting a 14 percent drop in likelihood. However, the research projects differed in the specific variations of the disease. For example, one found no reduced risk of breast cancer while the other demonstrated a tangibly smaller likelihood.
Explaining the discrepancies
Due to the vastly different research methodologies used, Weller says there is no unilateral agreement. Sample sizes, categorization of diet groups, and modeling techniques all differ between studies.
Often undisclosed lifestyle factors, including smoking and exercise, impact results too.
Lack of uniformity in research findings aside, Weller concludes his analysis by stating that eating less meat is a viable way to prevent cancer.
“Papers are based on large datasets and undoubtedly reveal that vegetarian diets can indeed decrease the risk of specific types of cancer,” Weller writes.
He added: “However, the protective effects of vegetarian diets on rare types of cancer may not have been detected in these studies because the numbers of affected patients were low. It is predictable that future studies will probably reveal further associations between vegetarian diets and risk reduction in other cancer types.”