More and more people are choosing to eat less meat. There are many reasons why people may choose to make this change, but health is often cited as a popular reason.
A large body of research has shown that plant-based diets can have many health benefits, including reducing the risk of chronic diseases, such as type 2 diabetes and heart disease. Two great studies EPIC-Oxford and the Adventist Health Study-2 – have also suggested that vegetarian or pescetarian diets (in which the only meat a person eats is fish or shellfish) may be associated with slightly lower overall consumption Cancer risk.
Limited research has shown whether these diets might reduce the risk of developing specific types of cancer. This is what our recent study wanted to discover. We found that eating less meat lowers a person’s risk of developing cancer, even the most common cancers.
We conducted a large-scale analysis of diet and cancer risk using data from the UK Biobank study (a database of detailed health and genetic information on almost 500,000 Britons). When the participants were recruited between 2006 and 2010, they filled out questionnaires about their diet, including how often they ate foods like meat and fish.
We then tracked the participants for 11 years using their medical records to understand how their health had changed during this time.
The participants were then classified into four groups based on their diet. About 53 percent were habitual carnivores (meaning they ate meat more than five times a week). Another 44 percent of the participants ate little meat (they ate meat five or fewer times a week). Just over 2 percent were pescetarians, while just under 2 percent of the participants were classified as vegetarian. We included vegans with the vegetarian group as there were not enough to study them separately.
Our analyzes were also adjusted to ensure that other factors that could increase cancer risk, such as age, gender, smoking, alcohol use, and sociodemographic status, were taken into account.
Compared to regular carnivores, we found that the risk of developing any type of cancer was 2 percent lower for low carnivores, 10 percent lower for pescetarians, and 14 percent lower for vegetarians.
Specific cancer risk
We also wanted to know how diet affected the risk of developing the three most common types of cancer seen in the UK.
We found that low-meat eaters had a 9 percent lower risk of colorectal cancer compared to regular meat eaters. Previous investigation has also shown that a higher intake of processed meat in particular is associated with an increased risk of colorectal cancer.
We also found that vegetarians and pescetarians had a lower risk of colorectal cancer, however this was not statistically significant.
We also found that women who ate a vegetarian diet had an 18 percent lower risk of postmenopausal breast cancer compared to those who ate meat regularly. However, this association was largely due to the lower average body weight observed in vegetarian women.
Previous studies have shown that being overweight or obese after menopause increases breast cancer risk. No significant associations were observed between risk of postmenopausal breast cancer between pescetarians and low-meat eaters.
Pescatarians and vegetarians also had a lower risk of prostate cancer (20 percent and 31 percent lower, respectively) compared to regular meat eaters. But it’s not clear whether this is due to diet or due to other factors, such as whether or not a person sought a cancer screening test.
Since this was an observational study (meaning we only looked at changes in a participant’s health without asking them to make changes to their diet), this means we can’t know for sure if the links we’ve seen are caused directly by the diet or if they are due to other factors.
Although we carefully adjusted the results to account for other important causes of cancer, such as smoking and alcohol use, it is still possible that other factors influenced the results we observed.
Another limitation of our study is that most of the participants (about 94 percent) were white. This means we don’t know if the same link will be seen in other ethnic groups. It will also be important for future studies to look at a more diverse population, as well as larger numbers of vegetarians, pescetarians, and vegans to explore whether this link between lower cancer risk and these types of diets is as strong as we observed.
It’s important to note that simply cutting out meat doesn’t necessarily make your diet healthier. For example, some people who follow a vegetarian or pescetarian diet may still eat low amounts of fruits and vegetables and high amounts of refined and processed foods, which can lead to health problems.
Most of the evidence showing an association between lower cancer risk and vegetarian or pescetarian diets also seems to suggest that higher consumption of vegetables, fruits, and whole grains might account for this lower risk.
These groups also do not consume red and processed meat, which is related to increased risk of colorectal cancer. But more evidence will be needed to fully explore the reasons for the results we observed.
The links between red and processed meat and cancer risk are well known, which is why it’s widely recommended people try to limit the amount of these foods they eat as part of their diet. It is also recommended that people eat a diet rich in whole grains, vegetables, fruits, and beans, as well as maintain a healthy body weight to reduce cancer risk.
Cody WatlingResearcher Doctor, Cancer Epidemiology Unit, Oxford University; Aurora Perez-Cornagosenior nutritional epidemiologist, Oxford Universityand Tim keyProfessor of Epidemiology, Oxford University.
This article is republished from The conversation under a Creative Commons license. Read the Original article.
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