Eating processed meat daily linked to higher risk of Type 2 diabetes: study

Consuming just 50 grams of processed meat daily — roughly equivalent to two slices of ham — is associated with a 15 percent higher risk of developing Type 2 diabetes over the next decade, according to a new study.

Published Tuesday in The Lancet Diabetes & Endocrinology, the study also found that eating 100 grams of unprocessed red meat daily, equivalent to a small steak, was linked to a 10 percent increased risk of developing Type 2 diabetes.

While this correlation does not establish causation, it adds to existing research raising concerns about the health impacts of processed meats.

“Consistent and strong findings for processed meat in relation to Type 2 diabetes, heart disease, and cancer have emerged,” said Nita Forouhi, a professor of epidemiology at the University of Cambridge and senior author of the study.

“Our research significantly contributes to the evidence base by incorporating a large population of nearly two million participants across 31 studies in 20 countries, including 18 studies that had not previously published their findings,” she told Global News in an email on Wednesday.

Type 2 diabetes occurs when the body becomes resistant to insulin or fails to produce enough, resulting in high blood sugar levels. It typically develops later in life and is often related to lifestyle factors such as diet and exercise. In contrast, Type 1 diabetes is an autoimmune disorder that destroys insulin-producing cells in the pancreas, usually beginning in childhood and requiring lifelong insulin therapy. Type 2 diabetes, which can often be managed with lifestyle changes and medication, affects over 500 million people globally and is projected to impact one billion by 2050.

In Canada, Type 2 diabetes is rapidly increasing, with more than 60,000 new cases annually, according to Health Canada. The condition can lead to serious complications such as blindness, heart disease, nerve damage, and stroke.

Study Findings
The study examined the impact of red meat, processed meat, and poultry consumption on Type 2 diabetes risk. Researchers used the global InterConnect project to analyze data from 31 study cohorts in 20 countries, involving 1.97 million participants. They considered variables like age, gender, health behaviors, energy intake, and body mass index.

The study found associations between both processed and unprocessed meats and Type 2 diabetes, with a smaller risk increase linked to poultry consumption. Daily intake of 100 grams of poultry was associated with an eight percent higher risk of Type 2 diabetes. However, further analyses suggested this association was less consistent, while the links between Type 2 diabetes and both processed and unprocessed meats remained robust.

“We found that regular poultry consumption might be associated with a potentially increased risk of Type 2 diabetes, but these findings need further research as different analytical approaches showed weaker results,” Forouhi said. “For now, it would be premature to offer guidance on poultry consumption based on these results. Our findings for processed meat and unprocessed red meat are strong and consistent across various analyses.”

Potential Mechanisms
The study notes that the mechanisms linking meat intake to Type 2 diabetes are not fully established. However, several potential explanations are considered.

Forouhi suggested that meat is often part of dietary patterns that include fewer fruits, vegetables, and fiber — foods beneficial to health. Additionally, people who consume more meat may also have lifestyle factors like higher alcohol consumption, smoking, and lower physical activity, which can affect Type 2 diabetes risk.

Meat consumption might increase diabetes risk through mechanisms that impair insulin sensitivity or pancreatic function. For example, red meat is high in saturated fats and low in healthier polyunsaturated fats. A 2016 study in Plos Medicine found that replacing saturated fats with polyunsaturated fats is linked to improved insulin resistance.

“Meat is a major source of haem iron, which has been associated with Type 2 diabetes risk. Certain cooking methods, such as high-temperature frying or grilling, may produce harmful chemicals called advanced glycation end-products,” Forouhi explained.

Trimethylamine N-oxide (TMAO), produced by gut bacteria from choline and L-carnitine found in red meat, might also play a role in increasing diabetes risk. Additionally, nitrate and nitrite additives used in processed meats to extend shelf life may be linked to a higher risk of Type 2 diabetes. A 2023 study in Plos Medicine found that higher exposure to these additives was associated with increased diabetes risk.

Reducing Diabetes Risk
The Canadian Food Guide recommends limiting processed meats like hot dogs, sausages, and ham due to their association with colorectal cancer risk. Instead, it suggests focusing on plant-based foods such as vegetables, fruits, whole grains, and plant-based proteins.

Regular consumption of these plant-based foods provides higher dietary fiber levels, associated with a lower risk of cardiovascular disease, colon cancer, and Type 2 diabetes.

The World Health Organization (WHO) also advises minimizing red and processed meat consumption.

“Red meat can be part of a healthy diet, especially during key life stages, due to its rich content of bioavailable vitamins and minerals, including iron and vitamin B12. However, excessive consumption of red and processed meats is associated with increased risks of non-communicable diseases, including cancer, cardiovascular disease, and Type 2 diabetes,” the WHO stated.

Forouhi recommends reducing meat servings, eating meat less frequently, or substituting it with alternative protein sources like fish, poultry, eggs, legumes, nuts, and whole grains.

Diabetes Canada advises that Type 2 diabetes can often be prevented or delayed through lifestyle changes such as healthier eating, increased physical activity, and weight management.

“A good starting point is incorporating more vegetables, plant-based proteins like beans and lentils, whole grains, lean meats, oily fish, nuts, and healthy oils like olive oil, while reducing highly processed foods, refined grains, sugary foods, and sugary drinks,” the organization said.