Context:

Type 5 diabetes has recently received official recognition by the International Diabetes Federation (IDF). It is a distinct form of the disease primarily affecting lean and undernourished adolescents and young adults in low- and middle-income countries (LMICs), This acknowledgment marks a significant development in global health, as the condition has long been overlooked in research and often misdiagnosed in clinical settings.

Understanding Type 5 Diabetes

• First reported in 1955 in Jamaica as “J-type diabetes,” the condition was later classified in 1985 by the World Health Organization (WHO) as “malnutrition-related diabetes mellitus.” However, due to insufficient evidence, the category was removed in 1999. Over the years, the condition has been observed in several countries, including India, Sri Lanka, Bangladesh, Uganda, Ethiopia, Rwanda, and Korea. An estimated 25 million people may currently be affected worldwide.
• Type 5 diabetes is characterized by inadequate insulin production due to prolonged undernutrition, particularly during critical periods of growth. Unlike Type 1 diabetes, which is autoimmune, or Type 2 diabetes, which involves insulin resistance, this type results from impaired beta-cell function in the pancreas caused by malnutrition.

Clinical Features and Markers

The condition is typically found in individuals with the following features:

• A body mass index (BMI) below 18.5 kg/m².
• Severely reduced insulin secretion, lower than in Type 2 diabetes and just above Type 1 levels.
• No autoimmune or genetic indicators.
• Reduced hepatic glucose production.
• Low levels of dietary protein, fibre, and essential micronutrients.
• A significantly lower percentage of body fat compared to individuals with Type 2 diabetes.

These markers differentiate Type 5 from other forms of diabetes and are especially prevalent in undernourished populations in LMICs.

Developmental Origins

The condition often originates in utero. Inadequate maternal nutrition can impair fetal development, including that of the pancreas, which may later result in reduced insulin production. If nutritional deficiencies persist after birth, the risk of developing this form of diabetes increases. In contrast, children who are undernourished at birth but later experience excessive weight gain may be more prone to developing Type 2 diabetes.

Treatment and Management

Management of Type 5 diabetes focuses on nutritional rehabilitation. A high-protein diet is critical, along with balanced intake of carbohydrates and fats to support healthy weight gain, particularly in individuals with low BMI and high physical activity. Anti-diabetic medications or insulin are prescribed based on blood glucose levels and treatment response, evaluated on a case-by-case basis.

Conclusion

The formal recognition of Type 5 diabetes addresses a long-standing gap in global health discourse. It highlights the relationship between chronic malnutrition and metabolic disorders, particularly in under-resourced settings. Strengthening maternal and child nutrition, along with expanding awareness and clinical capacity, is essential to tackling this under-recognised but significant public health issue.