- Dietary “guidelines” published September 30 suggest people should continue eating red meat and processed meat, contrary to previous evidence that they increase risk of cancer,heart disease, and other illnesses.
- The recommendations were based on a review of research showing that health benefits of eating less meat are “very small” and are supported by weak evidence. Plus, people find it difficult to cut back on meat eating, the authors said.
- It has since been revealed that the lead author of the study had previously received $US76,863 in funding from an organisation associated with the beef industry for research on saturated fat.
- Even before knowing that, nutrition professionals said the “guidelines'” conclusions were contradictory, flawed, and “irresponsible.”
- Major health and nutrition organisations continue to stand by their recommendations to limit red, and especially processed, meats to support long-term health.
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Most people are familiar with the common health advice to avoid red meat and processed meat, since they have been linked to a higher risk of cancer, heart disease, and other illnesses.
However, guidelines published September 30 in the Annals of Internal Medicine call that advice into question.
The report was developed by a panel of international researchers who conducted five reviews of available research on meat-eating, including its impact on cancer risk and cardiovascular health, as well as people’s attitudes toward meat. In total, the researchers looked at more than 100 studies including more than 6 million people, according to an editorial on the research.
The panelists found that eating less meat was linked to only a very small reduction in health risks. They also concluded that the evidence that link is based on is uncertain and may not exist at all. In addition, the researchers found meat eaters tended to highly value their carnivorous habits, and would be unlikely to change.
However, an update on the research found that an author of the study did not disclose ties with an organisation funded by the beef industry, and had in fact received $US76,863 in funding for previous research that would have been considered a conflict of interest, the Washington Post reported Tuesday.
The guidelines, however, had already attracted controversy from public health experts and nutritionists, who said the information was misleading, the conclusions were unwarranted, and the guidelines themselves were “irresponsible.”
The guidelines suggest health benefits of cutting down on meat may be minimal
The report’s “weak” recommendation to continue eating meat was based on the following main points, according to Bradley Johnston, lead author of the study and associate professor of community health and epidemiology at Dalhousie University in Toronto.
- Eating three fewer servings of meat a week leads to only a very small decrease in health risks, according to the research.
- The link between meat eating and health risks is very uncertain, based on analyses of prior research methodology.
- Most people who eat meat enjoy it, feel it has a positive impact on their health, and said they would have difficulty preparing healthful and appetizing meals without meat, according to a survey of people’s values and opinions on meat-eating.
“When we’re faced with evidence that’s low certainty, in the face of what people value, we made a weak recommendation [to continue eating meat,] which means people should make their own decisions based on potential risks,” Johnston said. “We hope this will lead to more informed decision making by the public.”
The study’s authors, however, have ties to AgriLife Research
The Annals of Internal Medicine, the journal that published the study, issued a correction on December 31, 2019, to reflect the author’s undisclosed conflict of interest.
Lead author Johnston had previously received $US76,863 in funding for a separate research analysis on saturated fat from AgriLife Research, park of Texas A & M University. According to the Washington Post, Agrilife spent $US4.5 million on beef research in 2019, half of which came from industry groups and half from federal government sources.
“When Dr. Johnston was asked about this grant, he agreed it should have been disclosed and agreed to make the change,” Annals editor-in-chief Christine Laine told the Post.
Other experts had already called the recommendations into question
Dr. Frank Hu, chair of the nutrition department at the Harvard T.H. Chan School of Public Health, was one of many health and nutrition experts that had beef with the guidelines when they were released in September. For one, he said the review actually supports current guidelines against eating meat.
“Their guidelines actually contradict their own data,” Hu told Insider. “They basically confirmed what we’ve known from previous studies, that high intake of meats is associated with increased risk of mortality, cardiovascular risk, some cancers, and diabetes.”
And yet, “they dismiss these results based on the limitations of some contributing research methods,” Dr. Nigel Brockton, vice president of research at the American Institute for Cancer Research, said in a statement issued with other health organisations in response to the new guidelines.
“We believe this is not in the best public interest,” Brockton continued. “Regularly eating processed meat, and higher consumption of red meat, increases your risk of colorectal cancer; suggesting that there is no need to limit these foods would put people at risk of colorectal cancer and further undermine public confidence in dietary advice.”
The study may also have been misleading in its evaluation of evidence
In their statement, the AICR and other health organisations also pointed out that calling the link between meat eating and health risks “uncertain” is a confusing assessment.
The research panel used a system known as GRADE to determine the quality of the prior evidence linking meat eating and health. However, Hu explained that the GRADE method was designed for prescription drug trials, not nutrition research.
“This system is not appropriate for most dietary and lifestyle factors because those aren’t amenable to large, randomised controlled trials,” he said.
For example, a high-quality study by the GRADE standard would involve assigning a group of people to eat large amounts of meat for five years or more, then seeing if it made them sick, Hu explained. “It wouldn’t be feasible and may be unethical,” he said.
The U.S. Department of Agriculture standards for evaluating nutritional research already exist, according to Hu, but that’s not what the panel relied on.
Hu also questioned the credibility of the panel itself, a majority of whom are methodologists who specialise in research methods and statistics, not nutrition. “It’s very strange because the so-called new guidelines are issued by a self-appointed panel not from any national or international organisation,” he said. “And it’s very unusual for statisticians to issue nutrition guidelines.”
Scott Bauer – United States Department of AgricultureIt takes a lot of environmental resources to produce meat.
The study doesn’t address the environmental impact of meat eating
Another critique: The research panel determined that environmental impact and animal welfare concerns were “outside the scope” of the health recommendations.
As a result, Hu said, it’s an important consideration, since the health of planet will most certainly affect the health of its occupants. “When you issue meat guidelines, it’s really a missed opportunity that environmental concerns are not addressed,” he said.
Most experts continue to recommend limiting red and processed meat
The Harvard T.H. Chan School of Public Health estimates that a moderate reduction in meat eating could prevent up to 200,000 deaths a year in the U.S. alone.
The AICR also stands by its conclusion that the best available evidence consistently links eating red meat, and especially processed meat, with a higher risk of cancer.
“Anything associated with health risks, we need to be cautious. I think this [new report] is very irresponsible from both a scientific and public health point of view,” Hu said. “It’s very odd to say that because meat eaters enjoy meat, we shouldn’t ask them to change their behaviour.”
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