Using data from the UK Biobank study ― a database of detailed genetic and health information from nearly 500,000 British people, Cody Z. Watling, Julie A. Schmidt, Yashvee Dunneram, Tammy Y. N. Tong, Rebecca K. Kelly, Anika Knuppel, Ruth C. Travis, Timothy J. Key, and Aurora Perez-Cornago conducted a large-scale analysis of diet and cancer risk.
Recruited between 2006 and 2010, the participants of the study completed questionnaires about their diet and were then tracked for 11 years using their medical records to understand how their health had changed during this time.
Participants were categorized into four groups based on the type of their diet. Around 53 percent of the participants were regular meat-eaters, meaning they ate meat more than five times a week. Meanwhile, 44 percent of participants were low meat-eaters or those who ate meat five or fewer times a week. Over 2 percent were pescatarians, while the remaining under 2 percent of the participants were classified as vegetarians. Vegans were included with the vegetarian group as there weren’t enough data to study them individually.
After adjusting the analyses of data to consider other factors that may increase cancer risks, such as age, sex, smoking, alcohol consumption, and sociodemographic status, the study found the risk of developing any type of cancer was 2 percent lower for low meat-eaters, 10 percent lower in pescatarians, and 14 percent lower in vegetarians, compared with regular-meat eaters.
The study also found that participants with low-meat diets had a 9 percent lower risk of colorectal cancer compared with regular meat-eaters. Though not statistically significant, the study also found that vegetarians and pescatarians, had a lower risk of colorectal cancer, compared with regular meat-eaters.
In comparison to regular meat-eaters, vegetarian women had an 18 percent lower risk of postmenopausal breast cancer, according to the study. It, however, noted that this link was largely due to the lower average body weight seen in women with vegetarian diets.
Furthermore, the study also found pescatarians and vegetarians had a lower risk of prostate cancer, 20 percent and 31 percent less respectively, compared with regular meat-eaters. It’s unclear, however, whether this is due to diet, or if it’s a result of other factors, like whether or not these participants sought cancer screening.
The authors of the study noted that the research is an observational study, meaning they only observed changes to the participants’ health without asking them to make changes to their diet. Given this method, it’s not 100 percent correct to assume that the links seen between the types of diet and cancer risk are directly caused by diet, as they may be due to other factors.
The researchers also pointed out that around 94 percent of the participants were white, so it’s not clear whether the same links will be seen in other ethnic groups
Since this isn’t the first study to show links between red and processed meat and cancer risk, the authors of the study reminded people that simply eliminating meat doesn’t necessarily make one’s diet healthier. For instance, some people who follow a vegetarian or pescatarian diet may still eat low amounts of fruits and vegetables and high amounts of refined and processed foods, which may lead to poor health. This is why it’s recommended that people consume a diet that includes whole grains, vegetables, fruits, and beans as well as maintain a healthy body weight in order to reduce their risk of cancer.