A controversial study has leading experts up in arms after it hinted that eating less red and unprocessed meat does not improve one's health, according to CNN.
The study, published on Monday in the American College of Physicians's journal Annals of Internal Medicine, suggests that "adults continue current unprocessed red meat consumption" as a "weak recommendation" based on "low-certainty evidence." Nutritional Recommendations (NutriRECs), an organization that proclaims itself "an independent group with clinical, nutritional and public health content expertise," produced the study but has since received backlash.
"Why would you make a 'weak' recommendation about eating red and processed meat?" asked Christopher Gardner, a nutrition scientist at Stanford School of Medicine. "I'm completely flabbergasted. I'm also really worried about how dangerous this is."
The study's authors claim that dietary guidelines set forth by the U.S. and U.K. governments, World Cancer Research Fund/American Institute for Cancer Research and the World Health Organization are all based on limited observational studies that do not detail the specific effects of consuming red or processed meat.
"The organizations that produce guidelines did not conduct or access rigorous systematic reviews of the evidence, were limited in addressing conflicts of interest, and did not explicitly address population values and preferences," the authors assert in their study.
The NutriRECS researchers said their findings, on the other hand, are based on a methodology called GRADE, otherwise known as the Grading of Recommendations, Assessment, Development and Evaluation.The methodology is meant to reduce confusion that may arise from multiple grading systems when it comes to evaluating recommendations and evidence.
"On the basis of 4 systematic reviews assessing the harms and benefits associated with red meat and processed meat consumption and 1 systematic review assessing people's health-related values and preferences on meat consumption, we suggest that individuals continue their current consumption of both unprocessed red meat and processed meat," the researchers wrote.
Some experts, however, say NutriRECS didn't properly apply GRADE, claiming instead that the measurement should be used to assess randomized clinical trials and not lifestyle studies like the ones NutriRECS referred to.
"We can't randomize people to smoke, avoid physical exercise, breathe polluted air or eat a lot of sugar or red meat and then follow them for 40 years to see if they die," Gardner said. "But that doesn't mean you have no evidence. It just means you look at the evidence in a more sophisticated way."
Furthermore, research already shows a link between processed meats such as ham, bacon, sausage, and corned beef and colorectal cancer, Oxford University epidemiologist Tim Key told CNN.
"There's substantial evidence that processed meat can cause bowel cancer — so much so that the World Health Organization has classified it as carcinogenic since 2015," he said.
In fact, the American Cancer Society estimates that there will be 101,420 new cases of colon cancer and 44,180 new cases of rectal cancer in the U.S. this year, many of which will most likely be linked to meat consumption.
"If the takeaway from this publication is 'red and processed meats are back,' that would be a disservice to the public," nutrition scientist Dr. Alice Lichtenstein, of the Cardiovascular Nutrition Laboratory at the Human Nutrition Research Center on Aging at Tufts University, said of NutriRECS's study.