Pune: A groundbreaking paper published in The Lancet has introduced the term type 5 diabetes, a unique form of diabetes associated with chronic undernutrition, calling for global attention and deeper research.
The classification follows an international consensus meeting in Vellore, India, in January 2025, which proposed this nomenclature to distinguish it from type 1, type 2, and other rare diabetes variants.
Global Experts Recognize Type 5 Diabetes as a Distinct Condition
The newly defined type 5 diabetes primarily affects individuals from undernourished and socioeconomically deprived populations in low- and middle-income countries. Unlike type 2 diabetes, it is characterized by insulin deficiency without obesity or ketoacidosis, and patients are typically lean or underweight.
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Dr Chittaranjan Yajnik, Head of the Diabetes Unit at KEM Hospital, Pune, and co-author of the paper, stated, “For decades, we have seen diabetes among people who are not obese or overnourished. Many such patients are lean or even underweight, especially in tropical and developing regions.” Historically termed “malnutrition-related diabetes,” this form has been documented across Africa, Jamaica, and India for over 75 years.
Research Highlights Genetic and Environmental Complexity
The Lancet study outlines that diabetes arises from the interplay of genetics and environmental triggers.
While type 1 diabetes involves immune destruction of insulin cells and type 2 diabetes results from insulin resistance linked to obesity, type 5 diabetes represents a condition caused by early-life nutritional deprivation.
Indian populations, particularly vulnerable due to low birth weights and the “thin-fat” body composition, exhibit a high prevalence of insulin-deficient diabetes.
Comparative studies across India and Sweden showed that two-thirds of Indian patients belong to insulin-deficient categories, while most Swedish patients are insulin-resistant. This evidence underscores the impact of early-life undernutrition in shaping the diabetes profile in developing nations.
Renewed Global Recognition by WHO and IDF
The paper also highlights the revival of global recognition for type 5 diabetes. Initially accepted by the World Health Organization (WHO) in 1985 as “malnutrition-related diabetes,” it was later removed in 1999 due to limited data.
However, in April 2025, the International Diabetes Federation (IDF) officially recognized type 5 diabetes as a distinct subtype and established a dedicated working group to study its causes and treatment.
Dr. Yajnik noted that this global acknowledgment would help channel research funding and foster collaboration among developing countries, especially India, which is expected to play a central role in future studies.
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The Path Ahead: Understanding Undernutrition and Diabetes Link
“While type 2 diabetes asks people to eat less and walk more, type 5 diabetes poses the opposite challenge – these patients already eat less and work hard,” said Dr. Yajnik. He emphasized the urgent need to explore its genetic, epigenetic, and nutritional mechanisms and design appropriate treatments.
As undernutrition re-emerges globally due to climate change, migration, famine, and conflict, experts believe that research on type 5 diabetes could have major implications for global health.
Proper documentation and targeted intervention strategies may help bridge the dual burden of malnutrition and diabetes in vulnerable populations.
