Study supports limiting red meat intake for type 2 diabetes prevention, highlights alternative protein sources

A study published in The American Journal of Clinical Nutrition shows that consumption of total, processed, or unprocessed red meat can significantly increase the risk of type 2 diabetes.

Study: Red meat intake and risk of type 2 diabetes in a prospective cohort study of United States females and males. Image Credit: myboys.me / Shutterstock

Background

With rapidly increasing prevalence, type 2 diabetes has become an epidemic health condition worldwide. Diabetes is a chronic metabolic disease characterized by persistently high blood glucose levels, which can potentially damage the cardiovascular system, kidneys, eyes, and nerves.

About 422 million people are affected by diabetes worldwide. The majority of these cases are found in low- and middle-income countries. Globally, about 1.5 million deaths occur each year due to diabetes.

Many observational studies have shown that consumption of red meat can increase the risk of type 2 diabetes. However, short-term randomized controlled trials could not find any significant effect of red meat consumption on biomarkers of hyperglycemia (high blood glucose) and inflammation.

Previously, in the Nurses’ Health Study (NHS), Nurses’ Health Study II (NHS II), and Health Professionals Follow-up Study (HPFS), a positive correlation was observed between red meat intake and incident type 2 diabetes. This association was further investigated in the current study, with more than 9,000 additional diabetes cases reported during the extended follow-up period of over 30 years.

Study design

The current study was conducted on 216,695 participants from the NHS, NHS II, and HPFS. The NHS (1976) and NHS II (1989) studies were conducted on registered female nurses from 11 and 14 US states, respectively. The HPFS study was conducted on various medical professionals from the US in 1986.

The participants’ dietary intakes were assessed every 2 to 4 years through food frequency questionnaires. The data on food and nutrient intakes obtained from the questionnaires was used to calculate the Alternative Health Eating Index (overall healthfulness of diet) and glycemic index.

Incident type 2 diagnoses were reported by the participants through biennial questionnaires. Afterward, a supplementary questionnaire regarding symptoms, diagnostic tests, and hypoglycemic therapy was provided to the participants who reported diabetes diagnosis.      

Important observations

The study analysis revealed a significant positive correlation between red meat intake and the risk of type 2 diabetes in all three study cohorts, either separately or combined. The participants with the highest intake of total red meat, processed red meat, and unprocessed red meat had 62%, 51%, and 40% higher risk of developing type 2 diabetes, respectively.

Every one serving per day induction in red meat, processed meat, and unprocessed meat was associated with 1.28-, 1.46-, and 1.24-times higher risk of developing type 2 diabetes. Overall, the analysis indicated almost a linear increase in type 2 diabetes risk across all red meat intake categories.

For an accurate dietary assessment, the dietary intake assessed by food frequency questionnaires was calibrated with 7-day weighed diet records obtained from a subgroup of participants. After calibration, more robust associations between red meat intake and diabetes risk were observed.

Before calibration, a 1-serving intake increment in red, processed, and unprocessed meat was found to increase the risk of type 2 diabetes by 28%, 50%, and 24%, respectively. After calibration, every 1-serving intake increment in red meat, processed meat, and unprocessed meat was found to increase the risk of type 2 diabetes by 47%, 101%, and 51%, respectively.  

The positive correlations between all categories of red meat intake and risk of diabetes remained consistent across subgroups defined by body mass index (BMI) and baseline hypertension. However, a higher risk of red meat-related diabetes was observed among participants with higher physical activity levels and among past smokers.

Substituting one serving per day of red meat with one serving per day of nuts and legumes and total dairy reduced the diabetes risk by 30% and 22%, respectively.    

Study significance

The study finds that intake of red meat in the forms of total meat, processed meat, or unprocessed meat can significantly increase the risk of type 2 diabetes. Moreover, the study reveals that the risk of type 2 diabetes can be reduced by replacing red meat with nuts, legumes, and total dairy products.

The study findings support the current recommendations for limiting red meat consumption and considering alternative protein sources for diabetes prevention.