Getty ImagesNewspaper headlines warn that ‘eating a ham sandwich a day’ increases the risk of type 2 diabetes, but experts say it’s not that simple.
The study of two million people in nearly 20 countries found a link to both red and processed meats, such as steak, bacon and sausages.
Although the research is well done, the findings are nuanced and should not cause fear or panic.
While it’s wise to limit your intake in line with healthy dietary guidelines, the researchers say this study shouldn’t mean you should take meat off the menu.
Links are not evidence
The study, published in the Lancet Diabetes and Endocrinology, has unavoidable limitations: it cannot prove that meat causes diabetes, because it is impossible to completely ignore all other possible risk factors, such as other foods eaten by the study participants and their lifestyle choices.
Dr Duane Mellor, from the British Dietetic Association, said: “The authors sought to control for other risk factors associated with an increased risk of developing type 2 diabetes, such as being overweight, smoking, alcohol and low vegetable intake.”
Although some data were missing about the effects of family history and waist circumference, which may be linked to diabetes, the researchers said they were confident in the associations they found.
Such studies assume that participants are telling the truth and can accurately recall what they ate.
So does that mean we should ignore the findings entirely?
No, not at all. This is just broadening our view of what foods, and in what amounts, are good or bad for us.
Prof Naveed Sattar, an expert in cardiometabolic medicine at the University of Glasgow, said: “This is an extremely well-conducted and important study, despite the necessarily observational nature of the evidence.”
“The data suggests that reducing red and processed meat in the diet may help protect people not only from heart disease and stroke, but also from type 2 diabetes, which is on the rise around the world.”
Colorectal cancer
The study found that eating two thick slices of ham (50 grams, 1.7 ounces) or a small steak (100 grams) per day was associated with risk.
Findings on chicken and other white meats were less clear.
The UK’s National Health Service (NHS) already advises people who eat more than 90g of red or processed meat a day (cooked weight) to cut back to 70g because experts believe eating too much processed meat could cause bowel cancer.
The International Agency for Research on Cancer places it in the same risk category as smoking and asbestos.
Processed meats are modified to improve flavor or extend their shelf life.
The chemicals and methods used, such as smoking, curing, or the addition of salt or preservatives, can be factors.
While meat is a good source of protein, vitamins and minerals, it can also contain high amounts of saturated fat, which has been linked to high blood cholesterol levels, a risk factor for coronary heart disease.
Blood glucose levels
Lead researcher Professor Nita Forouhi, from the University of Cambridge, said: “Our study provides the most comprehensive evidence to date of an association between consumption of processed and unprocessed red meat and an increased risk of future type 2 diabetes.”
“We support recommendations to limit consumption of processed and unprocessed red meat to help reduce the prevalence of type 2 diabetes in the population.”
Type 2 diabetes is a disease that causes high blood sugar levels because the body either produces too little of a hormone called insulin, or the insulin it does produce doesn’t work properly.
Risk factors include:
Obesity or overweight High blood pressure Ethnic family history
Dr Mellor offered a warning to people considering reducing their meat intake to ensure they continue to get enough important nutrients such as iron and vitamin B12.
“When considering reducing or removing certain foods from your diet, it is important that the replacement foods provide the same nutrients to maintain an overall healthy diet,” he said.
Good sources of vitamin B12 include:
Milk cheese eggs fortified yeast extracts (such as marmite), fortified breakfast cereals, fortified soy products
