Eating processed and red meat increases the risk of type 2 diabetes and eating just two slices of ham a day raises the risk by 15 percent, according to the largest study of its kind.
The Cambridge University-led study, involving two million people from around the world, provides the most comprehensive evidence to date of a link between meat and one of the most pressing dangers to global health.
More than 400 million people have been diagnosed with type 2 diabetes and it is a leading cause of blindness, kidney failure, heart attack, stroke and amputation. Evidence suggests that improving diet, along with maintaining a healthy weight and increasing physical activity, is one of the main ways to reduce the risk of the disease.
Experts in a meta-analysis of data from 1.97 million adults in 20 countries across Europe, North and South America, the eastern Mediterranean, southeast Asia and the western Pacific said their findings supported recommendations to limit processed and red meat intake.
Their findings were published in the journal The Lancet Diabetes and Endocrinology.
Lead author of the study, Professor Nita Forouhi, from the University of Cambridge, said: “Our study provides the most comprehensive evidence to date of an association between processed meat and unprocessed red meat consumption and an increased risk of future type 2 diabetes. It supports recommendations to limit processed and unprocessed red meat intake to reduce type 2 diabetes cases in the population.”
The researchers analysed data from 31 study groups through InterConnect, an EU-funded project to improve understanding of type 2 diabetes and obesity in different populations.
The research team found that habitual daily consumption of 50 grams of processed meat (equivalent to two slices of ham) was associated with a 15% increased risk of developing type 2 diabetes over the next 10 years.
They found that eating 100 grams of unprocessed red meat a day (the equivalent of one small steak) was associated with a 10% increased risk of the disease.
Habitual consumption of 100 grams of chicken per day was associated with an 8% higher risk. In further analyses to test the results under different scenarios, the association with chicken consumption weakened, but the associations between processed and unprocessed red meat and type 2 diabetes persisted, the researchers found.
“Our findings provide more comprehensive evidence than previously available about the association between chicken meat consumption and type 2 diabetes, but the association remains uncertain and needs to be further investigated,” Forouhi said.
In the UK, the NHS advises that anyone who eats more than 90g of red meat – such as beef, lamb, mutton, pork, veal, venison or goat – or processed meats such as sausages, bacon, ham, salami or corned beef a day should reduce this to 70g or less.
The researchers said the Interconnect data enabled the team to “more easily take into account various factors, such as lifestyle and health behaviors, that may influence the association between meat intake and diabetes.”
Lead author Dr Chunxiao Li, also from the University of Cambridge, said previous studies had combined existing results, but the new analysis looked at data from individual participants from each study.
Prof Nick Wareham, head of the MRC Epidemiology Unit at the University of Cambridge and lead author of the study, said the technique enabled the researchers to “provide more specific evidence about the association between consumption of different types of meat and type 2 diabetes than has been possible before”.
Experts not involved in the study said that while the study establishes association rather than causation, the results are consistent with current healthy eating recommendations.
Professor Navid Sattar, from the University of Glasgow, said: “This is an important study and, although the evidence is inevitably observational in nature, it is very well done. The data suggests that reducing red and processed meat in your diet could protect people not only from heart disease and stroke, but also from type 2 diabetes, which is on the rise around the world.”
Dr Duane Mellor, from Aston University, said the overall message to limit meat consumption was in line with advice to reduce the risk of type 2 diabetes, which includes a diet high in vegetables, fruit, nuts, seeds, beans, peas and lentils.
“This should also be accompanied by regular physical activity to minimise the risk of developing type 2 diabetes,” Mellor said.
