Many studies have tied red meat food to cancer and heart disease. But are the risks big enough to stop eating foods like lamb chops and hamburgers?
A team of international researchers says probably not.
Their findings, published as a series of papers Monday, go against established advice. A group of well-known U.S. scientists even took the unusual step of trying to stop publication until their criticisms were answered.
The new work does not say that red meat and processed meats such as hot dogs and bacon are healthy. It also does not suggest that people should eat more of such foods.
The new work examined past studies on red meat and health problems. The researchers involved generally support the finding that red meat is tied to cancer, heart disease and other serious health risks.
But the researchers also say the evidence is weak. They say there could be other causes for the apparent link -- including a person's other food choices and lifestyle.
Dr. Gordon Guyatt is with Canada's McMaster University. He was a co-writer of the new work. He said that most people who understand the degree of risks involved would say "Thanks very much but I'm going to keep eating my meat."
The new work is the latest example of the divisiveness in food research. Critics say scientific findings on the subject often have weak evidence. Defenders argue that nutrition studies can rarely be conclusive because of the difficulty of measuring the effects of any single food.
Methods have improved, however.
"What we need to do is look at the weight of evidence — that's what courts of law use," said Dr. Walter Willett, a professor of nutrition at Harvard University. He was among those calling for the papers' publication to be delayed.
Willett has led studies tying meat to bad health problems. He said the recent series of papers do not consider the especially clear benefits of changing from red meat to vegetarian choices.
In the papers, the writers sought to understand the possible effects of eating less meat. They noted the average of two to four servings a week eaten in North America and Western Europe.
They said the evidence for cutting back was not strong. For example, they found that cutting three servings of red meat a week would result in seven fewer cancer deaths per 1,000 people.
Based on the review, a panel of the international researchers said people do not have to cut back for health reasons. But they note their own advice is weak. They also note that they were not considering other possible reasons for eating less red meat -- such as concern for animals and the harmful effects to the environment.
There was disagreement even among the writers. Three of the 14 panelists said they support reducing red and processed meats in the human diet. And, a co-writer of one the papers also called for a publication delay.
The journal Annals of Internal Medicine defended the new work. It said the request to have it pulled before publication is not how scientific debate is supposed to happen.
Experts from Harvard, Yale, Stanford and other top American universities sent a letter to the journal asking that it "retract publication" of the papers. The experts said recommendations that could lead people to eat more red and processed meat were "irresponsible and unethical."
The World Health Organization's International Agency for Research on Cancer (IARC) and the World Cancer Research Fund (WCRF) both say red and processed meat may or can cause cancer.
I'm Ashley Thompson.