Eating iron-rich meat increases risk of type 2 diabetes

Highlights:

• Those with the highest intake of heme iron had a 26% higher risk of developing type 2 diabetes.
• An association was found between increased heme iron intake and elevated biomarker levels.

A new study suggests that high intake of heme iron may increase the risk of developing type 2 diabetes. Natural Metabolism showed.

The researchers also reported that an updated analysis of findings from retrospective cohort studies found an association between heme iron intake and higher levels of several biomarkers.

“Now, for the first time, we've put all the data together and are able to paint a pretty comprehensive picture of the relationship between heme iron, red meat and diabetes.” Frank B. HuDoctor of Medicine, Master of Public Health, PhD, “These findings suggest that the body's ability to produce high-quality, high-quality foods is crucial to maintaining a healthy diet,” Frederick J. Steer, professor of nutrition and epidemiology at Harvard University, told Healio.

According to background information from the American Red Cross, heme iron is found in foods such as meat, seafood, and poultry, while non-heme iron is found in vegetables, nuts, and fruits.

In the study, Hu and her colleagues evaluated 36 years of dietary data from 204,615 participants (79% women) from the Nurses' Health Studies I and II and the Health Professionals Follow-up Study.

The researchers also assessed plasma metabolic biomarkers in 37,544 participants and metabolic profiles in 9,024 participants to gain a deeper understanding of the biological mechanisms behind the association between diabetes and heme iron.

Overall, participants in the highest heme iron intake group had a 26% higher risk of developing type 2 diabetes compared with those in the lowest group (HR = 1.26; 95% CI, 1.2-1.33).

“A stronger unfavorable association with heme iron intake was observed in participants with lower BMI compared with those with higher BMI,” Hu et al. wrote.

The findings could be due to the potential impact of obesity on the body's ability to store iron, the researchers added.

The researchers reported no association between diabetes and increased intake of total iron, nonheme iron, or iron supplements.

Heme iron accounts for most of the association between unprocessed red meat intake and diabetes risk, “and also accounts for a moderate to moderate proportion in several dietary patterns,” Hu and his colleagues write.

The researchers also found an association between higher heme iron intake and increased levels of biomarkers such as leptin, C-peptide, triglycerides, and C-reactive protein, and identified several metabolites, including uric acid, that link heme iron to diabetes risk.

Hu and his colleagues note that the study has several limitations, including that most participants were white health professionals, making the findings unlikely to be generalizable to other diverse populations.

Furthermore, the researchers noted, “we were unable to identify other prospective cohorts with repeated measurements of heme iron intake and similar metabolic and metabolomic biomarkers to replicate our findings.”

“Iron is an essential nutrient, so it's a double-edged sword,” Hu explains. “On the one hand, iron deficiency is bad because it causes anemia, but on the other hand, excess iron, especially heme iron, is harmful because it increases inflammation and diabetes risk.”

He said that switching from a meat-based diet, especially one focused on red meat, to a plant-based diet “can significantly reduce your heme iron intake and therefore your risk of type 2 diabetes.”

Hu added that people who still want to eat animal products don't need to avoid red meat completely, but “can replace it with healthy plant-based proteins such as chicken, fish, nuts and legumes”.

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