Red meat and processed meat consumption linked to higher risk of type 2 diabetes, study of 2 million people finds

Meat consumption, particularly processed meat and unprocessed red meat, is associated with a higher risk of type 2 diabetes, according to an analysis of data from 1.97 million participants, published in The Lancet Diabetes and Endocrinologyfound.

Global meat production has increased rapidly in recent decades, and meat consumption exceeds dietary recommendations in many countries. Previous research has shown that higher consumption of processed meat and unprocessed red meat is associated with an increased risk of type 2 diabetes, but the results are mixed and inconclusive.

Poultry such as chicken, turkey, or duck is often considered an alternative to processed meat or unprocessed red meat, but fewer studies have examined the association between poultry consumption and type 2 diabetes.

To determine the link between consumption of processed meat, unprocessed red meat and poultry and type 2 diabetes, the team led by researchers from the University of Cambridge used the global InterConnect project to analyse data from 31 study cohorts in 20 countries. Their in-depth analysis took into account factors such as age, sex, health behaviours, energy intake and body mass index.

The researchers found that habitual consumption of 50 grams of processed meat per day, or the equivalent of two slices of ham, was associated with a 15% increased risk of developing type 2 diabetes within the next 10 years. Consuming 100 grams of unprocessed red meat per day, or the equivalent of a small steak, was associated with a 10% increased risk of developing type 2 diabetes.

Habitual consumption of 100 grams of poultry per day was associated with an 8% increased risk, but when further analyses were conducted to test the results under different scenarios, the association for poultry consumption became weaker, while the associations with type 2 diabetes for processed meat and unprocessed red meat persisted.

Professor Nita Forouhi from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge and lead author of the study, said: “Our research provides the most comprehensive evidence to date of an association between processed meat and unprocessed red meat consumption and a higher future risk of type 2 diabetes. It supports recommendations to limit processed meat and unprocessed red meat consumption to reduce the incidence of type 2 diabetes in the population.”

“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 investigated.”

InterConnect uses an approach that allows researchers to analyze individual participant data from multiple studies, rather than just published results.

This allowed the authors to include up to 31 studies in this analysis, 18 of which had not previously published results on the link between meat consumption and type 2 diabetes. By including these data from new studies, the authors significantly expanded the evidence base and reduced the risk of bias due to the exclusion of existing research.

Lead author Dr Chunxiao Li, also a member of the MRC Epidemiology Unit, said: “The previous meta-analysis pooled together previously published results from studies on the link between meat consumption and type 2 diabetes, but our analysis looked at data from individual participants in each study. This meant we were able to harmonise key data collected across studies, such as information on meat consumption and the development of type 2 diabetes.

“Using harmonised data also made it easier for us to take into account different factors, such as lifestyle or health behaviours, which may affect the association between meat consumption and diabetes.”

Professor Nick Wareham, Director of the MRC Epidemiology Unit and lead author of the paper, said: “InterConnect allows us to study risk factors for obesity and type 2 diabetes in populations from many different countries and continents around the world, helping to include populations that are under-represented in traditional meta-analyses.

“Most of the studies on meat and type 2 diabetes have been conducted in the United States and Europe, with some in East Asia. This research included additional studies conducted in the Middle East, Latin America and South Asia, and highlighted the need for investment in research in these regions and in Africa.

“Using harmonized data and unified analysis methods across nearly 2 million participants has allowed us to provide more concrete evidence of the link between consumption of different types of meat and type 2 diabetes than was previously possible.”