What to know about heme iron and diabetes risk
Heme iron in red meat is linked to type 2 diabetes risk. Bioengineered heme is being used to enhance the flavor of some plant-based meat products. Is that a cause for concern?
Heme iron makes blood red and meat taste savory—and it may help explain why people who eat a lot of red meat have a greater risk of developing type 2 diabetes than those who don’t. Now that synthesized, plant-based heme is being used in some vegetarian meat products, researchers at Harvard T.H. Chan School of Public Health wanted to give the molecule another look.
Iron is a mineral that helps carry oxygen in the body. As a nutrient, iron in the form of heme is found in animal-based foods and is more easily absorbed than the non-heme iron typically obtained from eating plant foods.
In a study published in August in Nature Metabolism, lead author Fenglei Wang, research associate in the Department of Nutrition, and colleagues found that heme iron was associated with increased type 2 diabetes risk while non-heme iron was not. Previous studies had relied on epidemiological data only. This study integrated years of dietary data from participants in Nurses’ Health Studies I and II and the Health Professionals Follow-up Study with metabolic biomarkers and cutting-edge metabolomics, which helped the researchers gain insight into the biological mechanisms underpinning the association between heme iron and type 2 diabetes risk.
Using blood samples from a subset of participants, they looked at conventional biomarkers—substances in the blood that indicate the presence of an abnormal process or condition. They found that heme iron was associated with biomarkers for inflammation and insulin activity, which are both potential pathways for type 2 diabetes.
They then used the samples from a smaller subset to check levels of small molecules (metabolites) derived from bodily processes. They identified 17 metabolites that may play a role in linking heme iron and type 2 diabetes risk.
“The metabolomic data complemented the collected dietary data by reflecting the biochemical reactions happening in the body after food intake,” Wang said. “By integrating multiple levels of data, we were able to gain a more comprehensive understanding of the association.”
Wang noted that in a paper he is working on for his thesis on fish intake and colorectal cancer risk reduction, metabolomics data were able to uncover an association that dietary questionnaires did not.
He and his colleagues did not specifically look at whether the source of heme iron made a difference. For example, one brand of plant-based meats enhances its products’ taste with heme produced from genetically engineered yeast.
Given that most people don’t eat a lot of plant-based burgers, it’s probably not a major concern, Wang said, although he noted that some of these products can be high in sodium. Regular burgers, which are high in cholesterol and saturated fat, are undoubtedly less healthy and it’s a good idea to decrease overall red meat consumption, he said.
Wang said he sympathized with people who may feel frustrated by nutrition studies telling them foods they like are bad for them. “We’re not asking people to stop eating everything,” he said. “We just want to provide information about what might be a better choice”
