No need to reduce consumption of red and processed meat, study claims

Adults should continue their current consumption of red meat and processed meat, according to the recommendations of an international panel published in Annals of Internal Medicine​.

The guideline—a striking departure from most existing recommendations—is based on the findings of four other papers published in the same issue, which review existing studies in the field to assess the risk of various cardiometabolic and cancer outcomes, incidence, and mortality.

A fifth paper provides a meta-analysis of studies examining people’s attitudes to meat and their resistance to dietary change. It concludes that “omnivores are attached to meat and are unwilling to change this behaviour when faced with potentially undesirable health effects.”​

The researchers - led by Dalhousie University and McMaster University in Canada - reviewed the same evidence others have looked at before. Their findings suggest if 1,000 people cut out three portions of red or processed meat every week for a lifetime, there would be seven fewer deaths from cancer. If they did it for 11 years, there would be four fewer deaths from heart disease

Meanwhile, if every week for 11 years, 1,000 people cut out three portions of red meat, there would be six fewer cases of type 2 diabetes. And if they did the same for processed meat, there would be 12 fewer cases of type 2 diabetes.

A radically different interpretation ​

Contemporary dietary guidelines recommend limiting consumption of unprocessed red meat and processed meat. US guidelines recommend limiting red meat intake, including processed meat, to around one weekly serving. UK dietary guidelines endorse limiting the intake of both red and processed meat to 70 g/d. The World Health Organization International Agency for Research on Cancer has indicated that consumption of red meat is “probably carcinogenic” to humans, whereas processed meat is considered “carcinogenic” to humans.

But the researchers say the risks are not that big and the evidence is so weak, they could not be sure the risks were real. They add these recommendations are primarily based on observational studies that can’t prove cause and effect. Healthier people might be more prepared to cut their meat intake, for example.

“Nutritional recommendations must acknowledge the low-certainty evidence and avoid strong ‘just do it’ recommendations that can, as evidenced by the many low-fat recommendations worldwide, be very misleading​,” they wrote. The paper added: “Generating higher-certainty evidence regarding the impact of red meat and processed meat on health outcomes would be, were it possible, both desirable and important.”​

Public health bodies still recommend cutting back meat ​

The conclusions of the study were challenged by health bodies including Public Health England, Cancer Research UK and the World Cancer Research Fund. In the UK, the British Nutrition Foundation pointed out that the magnitude of the increased risks related to red and processed meat consumption are small, but when considered across a population they could potentially affect a lot of people. “For example, one finding was that a decrease of 3 servings of red or processed meat per week could result in between 1-12 fewer cases of type 2 diabetes per 1,000 people​,” it said. “Applying this to a population of millions of people, this could potentially be equivalent to hundreds of thousands fewer cases.”​

It added that randomized trials are hard to conduct. “Randomized controlled trials are considered the gold standard in medical research but can be impractical or even impossible to conduct in the context of diet and disease where it can be difficult to enforce a strictly controlled diet on people for any period of time or to conduct a study over the years or even decades needed to monitor disease outcomes.​

“In this context, dietary guidance must be given using the best available evidence to provide the best possible outcomes for the population as a whole.”​

The BNF concluded it’s still sensible to follow existing guidance from Government, which suggests limiting red and processed meat to about 70g (cooked weight) per day – about 3 portions across a week. “This is in the context of a healthy, balanced diet, which comprises elements such as plenty of fruit and vegetables, wholegrains, pulses and fish, which are associated with benefits to health​,” it said.

Source​

Annals of Internal Medicine​

Unprocessed Red Meat and Processed Meat Consumption: Dietary Guideline Recommendations From the Nutritional Recommendations (NutriRECS) Consortium​

DOI: 10.7326/M19-1621