Large study shows low meat and meat free diets linked to lower cancer incidence
By Laurence Tabanao Gayao
I grew up in a family that had a diet with occasional small amounts of red meat or no meat at all most of the time. If there was meat that was given to our family, it would be cut up in small pieces and used as a flavoring for cooking vegetables. Most of our food came from our large family garden and the poultry we raised. The first time I ate a beef steak was on plane in my first trip to the United States at 26 years of age. At that time I did not know that one had to add pepper and salt to the steak. It tasted so flat but I had nothing else to eat so I just ate it with the potato that came with it.
Recent studies have shown those that have diets with small amounts of meat or no meat at all have lower risks for developing certain cancers.
For some types of cancer, including colorectal cancer, diet may be a major lifestyle factor contributing to the risk for the disease. But for other cancers, like breast cancer and prostate cancer, it’s not clear how direct the link really is, experts said. In the case of colorectal cancer processed meat is carcinogenic to Humans. This is not new info.
Processed meats are meats that have been preserved by smoking or salting, curing or adding chemical preservatives. They include deli meats, bacon and hot dogs. Eating processed meats increases your cancer risk. Unfortunately, when these processed meats are preserved, cancer-causing substances form.
Background for the study
Cancer is a leading cause of death worldwide, and in the United Kingdom (UK), 28% of all deaths in 2017 were attributable to cancer. Colorectal, breast, and prostate cancer collectively account for 39% of all new cancer diagnoses in the UK , and it has been estimated that nearly 40% of cancer cases may be preventable through modifiable factors.
BMC Study
The study*, recently just published in BMC Medicine Journal, analyzed data for more than 470,000 people that was collected as part of the UK Biobank medical database project. When they were recruited, none of these participants had cancer.
A little more than half of the participants reported that they were regular meat-eaters, meaning they ate processed meat, red meat, or poultry more than five times per week. Another 205,000 of the participants were categorized as low meat-eaters, meaning they ate meat fives times per week or less. There were also about 11,000 pescatarians and 8,700 vegetarians in the study. (The 446 vegans in the study were included in the vegetarian group.)
Their results showed that, after more than a decade of follow-up, regular meat-eaters had a higher risk for all cancers compared to the other dietary groups. Those who followed a low-meat diet — especially men — had a reduced risk for colorectal cancer, vegetarian postmenopausal women had a lower risk for breast cancer and being vegetarian or pescatarian was associated with a reduced risk for prostate cancer in men.
“The take-home message would definitely be that there could be a lower risk of cancer amongst vegetarians and pescatarians,” Watling said, but he added that more research is needed, particularly with larger groups of vegetarians, Cody Watling, lead author on the study and a doctoral student in the cancer epidemiology unit at the University of Oxford, told TODAY.
Watling noted that although the results are interesting, he cautioned against making real-world recommendations based on the findings. “I don’t know if we’re at that stage yet,” he said.
This study builds nicely on previous work from another major research project that looked at cancer risk in 10 European countries, Stephen Hursting, professor in the department of nutrition and the Lineberger Comprehensive Cancer Center at the University of North Carolina at Chapel Hill, told TODAY. “It clearly suggested vegetarians had a lower cancer risk, ” he explained, “but it wasn’t cancer site-specific.”
The new study adds to those findings by identifying that a diet involving less meat could be protective against specific cancer types, Hursting said, particularly colorectal cancer, breast cancer in postmenopausal women and prostate cancer. And because the researchers are drawing from UK Biobank data, “this is going to get better and better” as time goes on and the authors are able to draw in more from that data set, Hursting said. “It’s sort of like we’re getting the first taste of an early wine; as it ages it’s going to get more and more powerful.”
Diet is important for cancer risk, but other factors are too
The study’s findings fit generally with the “hundreds” of other papers looking at diet and cancer risk, Dr. Steven K. Clinton, professor in the divisions of medical oncology and urology at The Ohio State University, told TODAY. “This is one out of many papers that kind of fits into the conclusion that you should focus on a healthy dietary pattern (to help prevent cancer).”
*For BMC Medicine article: Risk of cancer in regular and low meat-eaters, fish-eaters, and vegetarians: a prospective analysis of UK Biobank participants: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02256-w
