What is the relationship between dietary iron intake and the risk of developing type 2 diabetes (T2D)?
A study led by researchers at Harvard T.H. Chan School of Public Health, analysed data spanning 36 years from over 200,000 adults enrolled in the Nurses’ Health Studies I and II and the Health Professionals Follow-up Study. The research focused on different forms of dietary iron: heme iron, predominantly found in red meat and animal products, and non-heme iron, found in plant-based foods.
Iron intake and T2D
It revealed a significant association between higher intake of heme iron and an increased risk of T2D. Participants with the highest heme iron intake faced a 26% higher risk of developing T2D compared to those with the lowest intake.
Lead author Fenglei Wang emphasised the study’s depth, combining epidemiological data with advanced metabolic biomarker analysis. This approach allowed researchers to uncover potential biological mechanisms linking heme iron to T2D risk.
They identified several metabolic biomarkers associated with insulin resistance and inflammation that were elevated in participants with higher heme iron intake.
The study found no significant associations between non-heme iron intake, whether from dietary sources or supplements, and T2D risk. This reinforces the unique impact of heme iron on metabolic health compared to its non-heme counterpart.
Beyond epidemiological findings, the study looked into participants’ metabolomic profiles, identifying specific blood metabolites linked to heme iron intake and T2D risk. These metabolites, including L-valine, L-lysine, and uric acid, offer insights into potential pathways through which heme iron influences diabetes risk.
Reducing iron intake
The implications of these findings are substantial for public health strategies and dietary guidelines. Co-author Frank Hu highlighted the importance of reducing heme iron intake, particularly from red meat, and promoting plant-based dietary choices to mitigate T2D risk. This advice is particularly relevant given the growing popularity of plant-based meat alternatives that may include added heme iron for flavour enhancement.
The study acknowledges certain limitations, including potential confounders in the data and the need for replication in more diverse populations beyond the predominantly white cohort studied.
This research underscores the role of dietary choices in preventing chronic diseases like diabetes. By reducing consumption of heme iron-rich foods and opting for plant-based alternatives, individuals can potentially lower their risk of developing type 2 diabetes and improve overall metabolic health.
