Vegetarians are 14 percent less likely than meat-eaters to develop any type of cancer

Whom did researchers look at?

The researchers analyzed data of more than 472,000 participants from the U.K. Biobank. Initiated in 2006, the U.K. BioBank has health and genetic data of over 500,000 individuals that serves as a handy database for researchers to determine health outcomes while including variables, such as diet, in this case. 

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The researchers created four categories of participants based on their diet; the first one included those who ate meat more than five times a week (regular meat-eaters), the second one consisted of those who consumed meat five times or less in a week (low meat-eaters), the third included the ones who eat fish only (fish-eaters) while the last one focused on those abstaining from eating meat or fish, namely, vegetarians. 

All individuals in the database had not displayed any signs of cancer when recruited and were followed up for over 11 years to see if they'd develop any.

At the end of 11 years, the researchers reported different types of cancers in these individuals, ranging from colorectal cancer to prostate cancer as well as postmenopausal breast cancer in women participants. However, the occurrence of cancer was the least in those who were on a vegetarian diet, while meat-eaters were at the most risk. 

Is eating fish better than eating meat? 

As the risk of developing any type of cancer was lower in individuals who consumed less meat in their diet, it was even lower for individuals who consumed fish in their diets. According to a press release from the World Cancer Research Fund (WCRF) that financially supported this study, the risk of developing cancer was lowered by 10 percent in individuals who ate fish. 

Compared to meat-eaters, fish-eaters had 20 percent less likelihood of developing prostate cancer, while vegetarians were 31 percent less likely to develop the same type of cancer. So for those who cannot switch to a plant-based diet right away, maybe switching to fish in the interim might be a better health option. 

In the study published in BMC Medicine, the researchers have clarified that the findings may also have been affected by other factors such as the body mass index (BMI) of the individuals. 

Study Abstract: 

       Background

Following a vegetarian diet has become increasingly popular and some evidence suggests that being vegetarian may be associated with a lower risk of cancer overall. However, for specific cancer sites, the evidence is limited. Our aim was to assess the associations of vegetarian and non-vegetarian diets with risks of all cancer, colorectal cancer, postmenopausal breast cancer, and prostate cancer and to explore the role of potential mediators between these associations.

       Methods

We conducted a prospective analysis of 472,377 UK Biobank participants who were free from cancer at recruitment. Participants were categorised into regular meat-eaters (n = 247,571), low meat-eaters (n = 205,385), fish-eaters (n = 10,696), and vegetarians (n = 8685) based on dietary questions completed at recruitment. Multivariable-adjusted Cox regressions were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for all cancer incidence and separate cancer sites across diet groups.