Higher Heme Iron Intake May Raise Risk of Developing Type 2 Diabetes: Study Finds

The new study published in Nature Metabolism and led by researchers at Harvard T.H. Chan School of Public Health reveals that increased consumption of heme iron, which is primarily found in red meat and other animal products, rather than non-heme iron from plant-based sources, was linked to a greater risk of developing type 2 diabetes (T2D).

The researchers investigated the relationship between iron intake and type 2 diabetes (T2D) by analysing 36 years of dietary data from 206,615 adults who participated in the Nurses' Health Studies I and II and the Health Professionals Follow-up Study. They evaluated participants' consumption of different types of iron—total, heme, non-heme, dietary (from foods), and supplemental (from supplements)—and their T2D status, while accounting for other health and lifestyle variables.

The researchers also explored the biological mechanisms linking heme iron to type 2 diabetes (T2D) within smaller participant groups. They analysed plasma metabolic biomarkers related to insulin, blood sugar, blood lipids, inflammation, and iron metabolism in 37,544 participants. Additionally, they examined the metabolomic profiles of 9,024 participants, which included plasma levels of small-molecule metabolites involved in processes like digestion and chemical reactions.

The study revealed a significant correlation between higher heme iron intake and increased T2D risk. Those in the highest intake group had a 26% greater risk of developing T2D compared to those in the lowest intake group. Furthermore, heme iron was found to contribute to over half of the T2D risk linked to unprocessed red meat and a notable portion of the risk associated with several T2D-related dietary patterns. Consistent with earlier research, no significant link was found between non-heme iron intake from diet or supplements and T2D risk.

The researchers also identified a dozen blood metabolites-; including L-valine, L-lysine, uric acid, and several lipid metabolites-;that may play a role in the link between heme iron intake and TD2 risk. These metabolites have been previously associated with risk of T2D.

The researchers believe the study’s findings have significant implications for dietary guidelines and public health strategies aimed at reducing diabetes rates. Specifically, the addition of heme to plant-based meat alternatives—used to improve flavor and appearance—raises health concerns and requires further investigation.

Reference:Wang, F., et al. (2024). Integration of epidemiological and blood biomarker analysis links haem iron intake to increased type 2 diabetes risk. Nature Metabolism. doi.org/10.1038/s42255-024-01109-5.