Type 5 Diabetes: A Long-Overdue Recognition of Malnutrition-Related Diabetes

t2diabetesnetwork
May 5
7 min read

In April 2025, the International Diabetes Federation (IDF) officially recognized a new type of diabetes, Type 5 Diabetes, long overlooked in traditional classifications. Type 5 diabetes (T5D) affects between 20 to 25 million people worldwide, primarily in regions such as Asia and Africa. In response to the rising rates, the IDF formed a working group specifically to explore this, co-chaired by Dr Meredith Hawkins, an endocrinologist and founding director of the Global Diabetes Institute at the Albert Einstein College of Medicine in New York, and Dr Nihal Thomas, a professor of endocrinology at Christian Medical College (CMC) in Vellore, Indian.

What is Type 5 Diabetes?

While type 2 diabetes (T2D) is often associated with overnutrition and metabolic syndrome, T5D stems from the opposite extreme—years of undernutrition, often beginning in childhood. Also known as malnutrition-related diabetes, primarily affects individuals with a low body mass index (BMI) who have experienced malnutrition during early childhood or sustained periods of undernutrition. In both cases, though, the pancreas becomes unable to maintain glucose homeostasis, highlighting the dual burden of malnutrition: both excess and deficiency can drive metabolic disease.

Speaking at the recent IDF World Diabetes Congress, Professor Schwarz said:

“The recognition of type 5 diabetes marks a historic shift in how we approach diabetes globally. For too long, this condition has gone unrecognised, affecting millions of people and depriving them of access to adapted care. With the launch of the Type 5 Diabetes Working Group, we are taking decisive steps to correct this. This is about equity, science, and saving lives.”

Historically referred to in literature as protein-deficient pancreatic diabetes (PDPD) or fibrocalculous pancreatic diabetes (FCPD). The pancreas, while anatomically intact, becomes functionally compromised, resulting in impaired insulin production. This functional deterioration is not due to β-cell destruction, but due to chronic metabolic stress and nutrient scarcity. In an era where climate change, political instability, and global economic shocks increasingly affect food systems, nutrition insecurity is rising—even in countries like Canada, the UK, and the United States. This underscores why T5D is no longer solely a disease of the Global South.

For years, people living with this form of diabetes were often misdiagnosed with type 1 or T2D, leading to inappropriate treatments. By officially classifying it as type 5, we now have a clearer understanding of its unique metabolic characteristics, which will allow for better diagnosis, care, and treatment tailored to this specific population.

With increasing awareness, however, similar pathophysiological patterns are now being identified in marginalized populations within high-income countries—raising concern that Type 5 diabetes is more widespread than previously acknowledged.

“Malnutrition-related diabetes is more common than tuberculosis and nearly as common as HIV/AIDS,” said Dr. Hawkins from IDF. “But without a name, we couldn’t identify patients or create therapies.”

Key Features of Type 5 Diabetes

Early Onset: Often develops before age 30.
Low BMI: Individuals maintain a BMI of <19 kg/m² due to chronic undernutrition.
No Ketones: Unlike typical type 1 diabetes, individuals with type 5 rarely experience ketones, even with uncontrolled blood glucose.
Insulin Resistance: They often require high doses of insulin but do not exhibit the same insulin resistance seen in type 2 diabetes.
Complications: Increased risk of diabetes-related complications, especially in the context of food insecurity and poverty.

Additionally and compared to T2D

Lower insulin secretion compared to lean individuals without diabetes.
Higher glucose production and uptake compared to individuals with type 2 diabetes.
Lower levels of visceral fat and hepatocellular lipids compared to type 2 diabetes patients.

These patients are often misdiagnosed with T1D because of their need for high insulin doses, even though they do not share the autoimmune features of type 1 or the typical insulin resistance seen in type 2.

A Brief History of Malnutrition-Related Diabetes

This form of diabetes has been recognized in medical literature for over 60 years. The condition was first observed by Hugh-Jones in Jamaica in 1955, where he encountered patients who didn’t fit the classic profiles of type 1 or type 2 diabetes. Their condition was associated with low BMI, early onset of diabetes, and a history of malnutrition.

In 1985, the World Health Organization (WHO) officially classified it as Malnutrition-Related Diabetes Mellitus (MRDM). However, in 1999, the WHO withdrew the classification due to insufficient evidence linking malnutrition directly to diabetes development.

Despite the removal of the classification, subsequent studies continued to support the existence of a unique form of diabetes among individuals with low BMI, especially in LMICs. Studies from countries such as India, Ethiopia, and Iran have shown that this condition is common among individuals who meet the criteria for MRDM, but who were previously misdiagnosed as type 1.

The reclassification of MRDM as T5D by the International Diabetes Federation in 2025 reflects this growing consensus in the scientific community and highlights an urgent need to revisit diabetes screening and treatment strategies in under-resourced populations.

The acknowledgment of Type 5 Diabetes not only closes a critical gap in our understanding of global diabetes epidemiology but also calls for the development of tailored, evidence-based treatment protocols. Importantly, it re-centres nutrition and poverty as key determinants of metabolic health—factors that have been underappreciated in the conventional classifications of diabetes until now.

The Importance of This Recognition

The recognition of T5D is critical for several reasons:

✅ Better Diagnosis: It allows healthcare providers to more accurately diagnose and treat individuals who would otherwise be misclassified as having type 1 diabetes. Understanding that this condition exists as a separate entity will prevent the overuse of insulin therapy, which can be dangerous in populations with food insecurity.

✅ Tailored Treatment Plans:

Because individuals with Type 5 Diabetes often have different metabolic profiles from those with type 1 or type 2, they require different management strategies. Research shows that many of these patients don’t need the aggressive insulin regimens that are typically used for type 1 diabetes. Reducing unnecessary insulin use can also prevent dangerous hypoglycemic episodes.

✅ A Step Towards Health Equity:

The majority of people affected by T5D live in low to middle income countries, where healthcare resources are often scarce. Recognizing this condition opens the door for more research, better diagnostic tools, and greater awareness, ultimately improving healthcare for vulnerable populations.

Connecting T5D and T2D: The Nutritional Link We’re Missing

At first glance, Type 2 and Type 5 diabetes seem worlds apart. But despite their different appearances, these two forms of diabetes are more connected than we might think—especially when it comes to micronutrient deficiencies, sometimes referred to as hidden hunger.

A recent systematic review and meta-analysis in BMJ Nutrition, Prevention and Health (2025) pulled data from over 130 studies and 52,000 people with T2D across the globe. What it found was eye-opening: nearly half of those withT2D had at least one important micronutrient deficiency.

45.3% of people with Type 2 diabetes were missing key micronutrients
Women were more affected than men (48.6% vs. 42.5%)
The most common deficiencies were:
- Vitamin D – 60.45%
- Magnesium – 41.95%
- Iron – 27.81%
- Vitamin B12 – 22.01%
Among those on metformin (a common diabetes medication), B12 deficiency jumped to 28.72%

“These deficiencies may act as catalysts in the pathways leading to several diseases like type 2 diabetes.”— Mangal D, et al., 2025

You don’t have to be underweight to be undernourished. Even people with obesity—often seen in T2D—can be malnourished at the cellular level. Micronutrient shortfalls can mess with insulin signaling, hinder pancreatic function, and throw glucose metabolism out of balance.

That’s where T5D comes back into the picture. It’s already been shown to stem from undernutrition—but now, we’re realizing that some of the same deficiencies show up in Type 2, just wearing a different disguise. So instead of seeing these two types as opposites, it might make more sense to think of them as different expressions of the same underlying issue: the body not getting what it needs to regulate blood sugar properly.

These results highlight how subclinical malnutrition—even in the presence of obesity or normal weight—can interfere with insulin signaling, pancreatic function, and glucose metabolism.

Thus, the biological boundary between Type 2 and Type 5 diabetes is increasingly blurred.

What’s Next?

The reclassification of T5D is just the beginning of a much-needed shift in how we understand and manage diabetes. Although T5D is still emerging in the scientific community, it brings to light the need for more research to define and treat this condition, especially in resource-limited settings. As we gain a clearer picture, it’s likely that we’ll see new approaches to diagnosis and treatment for those living with T5D, a form of diabetes often connected with malnutrition in low- and middle-income countries.

An important area for progress will be improving diagnostic criteria. As research continues, we’ll likely develop better and more accurate tests that can differentiate T5D from other forms of diabetes, particularly Type 2 Diabetes (T2D). This is critical because while both types share certain features, they have distinct metabolic processes that require tailored management.

In addition to better diagnostic tools, there is a growing call for more research funding to focus on malnutrition-related diabetes, especially in low-income countries. Much like T2D, T5D is intricately tied to nutrition, and increased funding will help us understand these conditions better and, ultimately, improve outcomes for affected populations.

Another important area of focus will be global health advocacy. There is a rising awareness of the intersection between nutrition, poverty, and chronic diseases like T2D and T5D. The connection between food insecurity and diabetes, particularly in regions with limited resources, is becoming impossible to ignore. As more attention is given to this issue, we can advocate for policies that ensure people in food-insecure regions receive the care and support they need.

What This Means for Clinical Practice

For healthcare providers, the implications of T5D and T2D will shape daily clinical practices. One of the most immediate changes is making nutrition screening a routine part of diabetes care. Patients with either T5D or T2D, especially those with low BMI, chronic illness, or a history of food insecurity, should be assessed for micronutrient deficiencies and malnutrition. By screening for these issues early, we can identify potential complications that may contribute to disease progression and intervene before they worsen.

In addition to screening, tailored supplementation will become an essential part of managing both T2D and T5D. Both conditions are often linked to specific micronutrient deficiencies, including vitamin D, magnesium, iron, and B12. These deficiencies can interfere with insulin sensitivity and glucose metabolism, making it crucial to integrate routine screenings for these vitamins and minerals into diabetes management plans. For patients taking metformin—a common medication for T2D—it’s especially important to monitor B12 levels, as long-term use of the drug can lead to deficiencies.

Lastly, healthcare providers can play a crucial role in supporting food security initiatives. By advocating for policies that increase access to nutritious, affordable food, particularly for vulnerable populations such as children, seniors, and individuals with chronic illnesses, we can help reduce the risk of malnutrition-related diabetes and improve the overall health of these communities.

🌐 Learn More

Read more about this atypical diabetes
Learn about the T5D at the IDF Diabetes
Learn more about micronutrient deficiency in T2D
Discover how social determinants of health impact diabetes care by joining us at our upcoming vodcast June 3rd, 2025 Register here