- Higher intake of heme iron, which is found in red meat and other animal products, may significantly increase the risk of type 2 diabetes, according to a new study.
- Researchers found that those who consumed the highest amount of heme iron had a 26% higher risk of developing type 2 diabetes than those consuming the least amount.
- Experts say diets that emphasize higher consumption of red meat are well documented to present their own health risks, and even some plant-based meat alternatives may have unhealthy levels of heme iron added, along with other processed ingredients.
A new study suggests that heme iron, which is found in red meat and other animal products, may significantly contribute to the risk of type 2 diabetes.
The study, led by researchers at Harvard’s T.H. Chan School of Public Health and published in
The study’s data was based on nearly four decades’ worth of research from the Nurses’ Health Studies I and II and the Health Professionals Follow-up Study. Researchers looked at reports for 206,615 adults enrolled in those studies and examined all the ways they consumed iron, from food to supplements, and their development of type 2 diabetes.
Among smaller subsets of participants, they also studied their blood plasma levels of metabolic biomarkers, including markers of insulin levels, blood lipids, blood sugar, inflammation, and iron overload, and the potential metabolic pathways between heme iron and type 2 diabetes.
People who consumed the most heme iron had a 26% higher risk of type 2 diabetes than those who ate the least. The researchers also found that higher heme iron consumption was associated with metabolic biomarkers linked to the development of type 2 diabetes, along with lower levels of beneficial biomarkers.
They also identified a dozen blood metabolites — small molecules produced during metabolism — that may be involved in the link between heme iron intake and the risk of type 2 diabetes.
It’s important to note that the study had several limitations, such as not accounting for all confounding factors and potential measurement errors in the data. The participants were also predominantly white, so the results may not apply to other racial and ethnic groups.
Diets heavy on meat, like paleo, ketogenic, and others, have seen a rise in popularity in recent years, in part due to their high protein levels. However, some Healthcare experts have questioned the overall Health benefits of low-carb, high-fat/high-protein diets, pointing to existing research that suggests it is not sustainable.
Dr. Matthew O’Brien, MD, MSc, an associate professor of medicine and preventive medicine at Northwestern University, who was not involved with the study, said many of these diets carry health risks.
Over the years, self-proclaimed weight loss experts and influencers have touted many diets that focus on eating large amounts of meat and very low carbohydrates. These include the Atkins, South Beach, Paleo, and keto diets. While these diets have been shown to promote rapid weight loss, they are very difficult to sustain long-term, and they are associated with some Health risks. The current study, as well as prior research on this topic, suggests that eating large quantities of red meat, or even moderate amounts, may elevate the risk of developing type 2 diabetes.
Melanie Murphy Richter, a registered dietitian nutritionist and the director of communications for the nutrition company Prolon, who was not involved in the study, told Medical News Today that there are a number of factors at play in the popularity of meat-based diets: an emphasis on physique over longevity, a demonization of carbohydrates, a glut of highly processed foods, and unequal access to healthy plant-based alternatives.
“In all my years as a dietitian, I’ve never encountered such a strong emotional attachment to a specific macronutrient. Protein has become the dietary darling, and anyone who challenges its prominence—no matter how well-supported by evidence—can expect significant backlash. However, the truth is that
excessive protein consumption , particularly from animal sources like meat, eggs, and dairy, has been well documented to accelerate aging and increase the risk of age-related diseases such as type 2 diabetes, cardiovascular disease, andall-cause mortality .”
— Melanie Murphy Richter, registered dietitian nutritionist
“When we consume animal protein, it activates a growth factor called mTOR. While mTOR is essential during specific life stages, like childhood and [adolescence] when growth is a priority, overstimulation of this growth factor [adulthood] can
Dr. O’Brien said that many plant-based diets are well known to have significant health benefits and lower risks of chronic diseases — like diabetes — and cardiovascular issues.
“The Mediterranean diet has been studied most widely, which has a foundation of plant-based foods and incorporates some poultry, fish, eggs, cheese, and yogurt,” Dr. O’Brien said. “Research has also shown that more strict vegetarian diets and vegan diets that focus mostly on plant-based foods also confer a lower risk of chronic diseases and some cancers.”
Richter endorsed a diet based on whole foods: nutrient-dense vegetables, fruits, nuts, legumes, and seeds. But she cautioned that many widely available meat substitutes can be just as bad as other processed foods.
“The heme used in some plant-based meats is typically derived from genetically modified yeast, which, while generally considered safe, may still raise concerns for some people. Many plant-based meat alternatives are highly processed, containing high levels of sodium, artificial additives, and unhealthy fats. This can make them less suitable for those who are sensitive to sodium or trying to avoid processed foods. They may not offer the same nutritional benefits as whole plant foods, so relying on them too heavily could lead to an unbalanced diet.”
— Melanie Murphy Richter, registered dietitian nutritionist
Richter said that iron supplements’ benefits depend on an individual’s health situation. Women who are menstruating or pregnant, for example, may need extra iron to meet their body’s needs. But she still suggests turning to foods before supplements for essential minerals like iron.
“Whenever possible, it’s best to prioritize getting your nutrients from food before turning to supplements. Iron supplements can be hard on the stomach and often don’t absorb as well as iron from whole foods. Whole foods offer synergistic nutrients that aid in digestion and absorption,” Richter said.
“If someone is trending anemic (low iron), I always suggest first prioritizing high-iron foods like lentils, chickpeas, spinach, and pumpkin seeds. Pair these with vitamin C-rich foods like citrus or tomatoes to enhance the bioavailability of the iron. Start with this approach, and if you still need additional support, then consider an iron supplement.”
— Melanie Murphy Richter, registered dietitian nutritionist
Taking too much iron can be dangerous, and result in iron toxicity, so it’s advisable to talk with a doctor before taking iron supplements.
