What Is Type 5 Diabetes? A Comprehensive Report on the Newly Defined Type of Diabetes

Type 5 diabetes is a form of diabetes that primarily occurs in individuals who have been exposed to long-term protein–energy malnutrition and is characterized by a marked reduction in insulin production. This condition:

• Is not autoimmune in origin like classical Type 1 diabetes
• Is not based on insulin resistance like Type 2 diabetes

The fundamental problem lies in the insufficient development or functional loss of pancreatic β-cells.

Type 5 diabetes has most frequently been reported in:

• Individuals with a history of chronic undernutrition during childhood or adolescence
• Populations in low- and middle-income countries
• Individuals who are underweight or of normal weight but have elevated blood glucose levels

For this reason, many patients who did not fully meet the diagnostic criteria for Type 1 or Type 2 diabetes remained in a long-standing “gray area.”

The symptoms of Type 5 diabetes often overlap with those of Type 1 and Type 2 diabetes:

• Persistent thirst
• Frequent urination
• Fatigue
• Weight loss
• Increased susceptibility to infections

However, the distinguishing feature is a lower-than-expected insulin requirement and the absence of significant insulin resistance.

Universal diagnostic criteria for Type 5 diabetes have not yet been clearly established. However, the following elements are important in clinical evaluation:

• A history of malnutrition
• Low or normal body mass index (BMI)
• Low C-peptide levels (indicating reduced insulin production)
• Negative autoimmune diabetes markers (such as GAD, ICA, etc.)

In this respect, Type 5 diabetes represents a clinical condition that requires careful differential diagnosis.

The most critical distinction in the treatment of Type 5 diabetes is that nutrition is placed at the center of therapy. Key treatment approaches include:

• Ensuring adequate and balanced nutrition
• Correcting protein and micronutrient deficiencies
• Low-dose insulin therapy in selected patients
• Limited and cautious use of oral antidiabetic medications

High-dose insulin treatments applied due to misclassification can increase the risk of hypoglycemia.

The recognition of Type 5 diabetes will:

• Enable millions of misdiagnosed patients to receive appropriate treatment
• Allow for a more accurate estimation of the global diabetes burden
• Improve understanding of the relationship between malnutrition and metabolic diseases

This approach is of major importance, particularly from a global health policy perspective. Indeed, the World Health Organization and international diabetes working groups emphasize the need to update diabetes classifications to include socioeconomic and nutrition-based factors.

Type 5 diabetes once again demonstrates that diabetes is not merely a “sugar disease,” but a condition directly linked to nutrition, development, and public health. In the coming years, as diagnostic criteria become clearer and the condition is incorporated into clinical guidelines, Type 5 diabetes is expected to become more visible within healthcare systems.