Eating processed or red meat increases the risk of type 2 diabetes, with just two slices of ham a day increasing the risk by 15%, the largest study of its kind suggests.
Research led by the University of Cambridge and involving 2 million people worldwide, provides the most comprehensive evidence yet of a link between meat and the disease that poses one of the most pressing threats to global health.
More than 400 million people have been diagnosed with type 2 diabetes, which is a leading cause of blindness, kidney failure, heart attacks, strokes and amputation of lower limbs. Besides maintaining a healthy weight and exercising more, evidence suggests that one of the most important ways to lower the risk of the disease is to improve diet.
Experts who conducted a meta-analysis of data involving 1.97 million adults from 20 countries across Europe, the Americas, the eastern Mediterranean, Southeast Asia and the western Pacific, say the results support recommendations to reduce the consumption of limit processed and red meat.
Their findings were published in the Lancet Diabetes & Endocrinology journal.
Prof Nita Forouhi, from the University of Cambridge, a senior author of the study, said: “Our research provides the most comprehensive evidence to date of a link between eating processed meat and unprocessed red meat and a higher future risk of type 2 diabetes. This supports recommendations to limit the consumption of processed meat and unprocessed red meat to reduce type 2 diabetes cases in the population.”
Researchers analyzed data from 31 study groups through InterConnect – an EU-funded project to understand more about type 2 diabetes and obesity in different populations.
They found that usual daily consumption of 50g of processed meat – equivalent to two slices of ham – was associated with a 15% higher risk of type 2 diabetes in the next 10 years.
The consumption of 100 g of unprocessed red meat per day – the equivalent of a small steak – was associated with a 10% higher risk of the disease.
Habitual consumption of 100g of poultry per day was associated with an 8% higher risk. When further analyzes were conducted to test the findings under different scenarios, the association for poultry consumption weakened, but the associations with type 2 diabetes for processed meat and unprocessed red meat persisted, the researchers found.
“While our findings provide more comprehensive evidence on the link between poultry consumption and type 2 diabetes than previously available, the link remains uncertain and requires further investigation,” Forouhi said.
In the United Kingdom, the NHS advise those who eat more than 90g of red meat such as beef, lamb, mutton, pork, veal, venison and goat, or processed meat such as sausage, bacon, ham, salami and cornmeal a day, to up to 70 g or less to cut.
The InterConnect data enabled the research team to “more easily account for different factors, such as lifestyle or health behaviors, that may influence the relationship between meat consumption and diabetes”, the researchers said.
Lead author Dr Chunxiao Li, also from Cambridge, said that while previous studies pooled existing results, the new analysis examined data from individual participants in each study.
That technique, says Prof Nick Wareham, director of the MRC Epidemiology Unit at Cambridge and a senior author on the paper, allowed researchers to “provide more concrete evidence of the link between consumption of different types of meat and type 2 diabetes than was previously possible”.
Experts not involved in the research said that although it only proved an association, and not causation, the results were in line with current recommendations for healthy eating.
Prof Naveed Sattar, from the University of Glasgow, said: “This is an important study which, despite the inevitable observational nature of the evidence, is very well done. The data suggest that cutting red and processed meat from the diet can protect people not only 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 overall message for moderate meat intake was consistent with advice to reduce the risk of type 2 diabetes, including a diet heavy on vegetables, fruit, nuts, seeds, beans, peas and lentils.
“This should be accompanied by regular physical activity to reduce the risk of developing type 2 diabetes,” Mellor said.
