Eating processed or red meat increases the risk of type 2 diabetes, and two slices of ham a day increases the danger by 15%, according to the largest study of its kind.
Research led by the University of Cambridge and involving 2 million people around the world provides the most comprehensive evidence yet of a link between meat and the disease that poses one of the most urgent dangers to global health.
More than 400 million people have been diagnosed with type 2 diabetes, a leading cause of blindness, kidney failure, heart attack, stroke and lower limb amputation. In addition to maintaining a healthy weight and increasing physical activity, evidence suggests that one of the most important ways to reduce the risk of developing the disease is to improve your diet.
Experts who conducted a meta-analysis of data from 1.97 million adults from 20 countries in Europe, the Americas, the Eastern Mediterranean, Southeast Asia and the Western Pacific say the findings support recommendations to limit consumption of processed and red meat.
Their results were published in the journal Lancet Diabetes & Endocrinology.
Professor Nita Forouhi, from the University of Cambridge and lead author of the study, said: “Our research provides the most comprehensive evidence to date of a link between consumption of processed meat and unprocessed red meat and a higher future risk of type 2 diabetes. It supports recommendations to limit consumption of processed meat and unprocessed red meat to reduce the incidence of type 2 diabetes in the population.”
The researchers analysed data from 31 study groups via InterConnect – an EU-funded project to better understand type 2 diabetes and obesity in different populations.
They found that a typical daily consumption of 50g of processed meat – the equivalent of two slices of ham – was associated with a 15% higher risk of developing type 2 diabetes over the next 10 years.
Eating 100g of unprocessed red meat per day – the equivalent of a small steak – was associated with a 10% higher risk of developing the disease.
Habitual consumption of 100g of poultry per day was associated with an 8% increased risk. When further analyses were conducted to test the results under different scenarios, the association with poultry consumption became weaker, but the associations with type 2 diabetes for processed meat and unprocessed red meat persisted, the researchers found.
“Although our results provide more comprehensive evidence on the association between poultry consumption and type 2 diabetes than was previously available, the link remains uncertain and needs to be further studied,” Forouhi said.
In the UK, the NHS advises those who eat more than 90g of red meat such as beef, lamb, mutton, pork, veal, venison and goat, or processed meat such as sausages, bacon, ham, salami and corned beef per day to reduce their intake to 70g or less.
The InterConnect data allowed the research team to “more easily account for different factors, such as lifestyle or health behaviors, that may affect the association between meat consumption and diabetes,” the researchers said.
Lead author Dr Chunxiao Li, also from Cambridge, said that while previous studies had pooled existing results, the new analysis looked at data from individual participants in each study.
According to Professor Nick Wareham, director of the MRC Epidemiology Unit at Cambridge and lead author of the study, this technique allowed researchers to “provide more concrete evidence of the link between the consumption of different types of meat and type 2 diabetes than was previously possible”.
Experts not involved in the study said that although it only proved an association, not causation, the results were consistent with current healthy eating recommendations.
Professor Naveed Sattar, from the University of Glasgow, said: “This is an important study which, despite the inevitably observational nature of the data, is very well done. The data suggest that removing red and processed meat from the diet could not only protect people from heart disease and stroke, but also from type 2 diabetes, a disease that is on the rise worldwide.”
Dr Duane Mellor, of Aston University, said the general message in favour of moderate meat consumption was consistent with advice to reduce the risk of type 2 diabetes, including a diet rich in vegetables, fruit, nuts, seeds, beans, peas and lentils.
“This should be accompanied by regular physical activity to minimise the risk of developing type 2 diabetes,” Mellor said.
