Heme iron found in red meat, animal products may raise diabetes risk by 26%

• 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 that even some plant-based meat alternatives may have unhealthy levels of heme iron added, along with other processed ingredients.
• These findings support similar results from another study which found that eating an equivalent of two slices of ham a day was linked to a 15% higher risk of developing type 2 diabetes in the next 10 years.

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 Nature Metabolism , points to a link between the development of type 2 diabetes and higher consumption of heme iron. The researchers were also concerned about the addition of heme iron to plant-based meat alternatives, as a way to mimic some of the flavor and appearance of real meat.

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.

How are meat-based diets linked to type 2 diabetes?

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.

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.

Similarly, a recent study, published in The Lancet Diabetes and Endocrinology and based on an analysis of data from 1.97 million participants, found that consuming 50 grams of processed meat a day — which is roughly equal to two slices of ham — may increase the risk of developing type 2 diabetes by 15%. Upping this amount to 100 grams a day was linked to a 10% increase in risk.

The same study also found a weaker association between poultry such as chicken or turkey and type 2 diabetes risk with 100 grams a day linked to an 8% higher risk. The study indicated that replacing processed meat with either unprocessed red meat or poultry was linked to a lower 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, and all-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 accelerate cellular aging ,” Richter said.

Are all plant-based meat alternatives healthy?

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,” 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

Should I take iron supplements instead of getting iron via food?

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 .