Type 5 diabetes, previously known as malnutrition-related diabetes mellitus (MRDM), is a distinct form of diabetes linked to chronic undernutrition during adolescence and young adulthood, insulin deficiency and health disparities. The condition primarily affects people in low- and middle-income countries (LMICs), especially in South-East Asia and sub-Saharan Africa.
What is type 5 diabetes?
Type 5 diabetes was formerly classified as malnutrition-related diabetes mellitus (MRDM). The new classification was endorsed by the International Diabetes Federation (IDF) at the World Diabetes Congress 2025 in Bangkok, Thailand. The condition is now acknowledged as the fifth classification of diabetes, alongside types 1, 2, 3c and gestational diabetes. This recognition marks a milestone in addressing a long-overlooked condition and advancing health equity in diabetes care for the millions affected globally. The classification also helps improve understanding of metabolic health in young adults living in under-resourced settings.
What makes type 5 diabetes different
| Feature | Type 1 diabetes | Type 2 diabetes | Type 5 diabetes (malnutrition-related) |
|---|---|---|---|
| Main cause | Autoimmune beta-cell destruction → very low insulin | Insulin resistance + progressive beta-cell decline | Insulin deficiency linked to chronic undernutrition / impaired pancreatic function |
| Typical body type | Any (often lean at diagnosis) | Often overweight/obesity (not always) | Often lean/low BMI; history of undernutrition |
| Autoantibodies | Often positive (e.g., GAD, IA-2, ZnT8) | Usually negative | Usually negative (helps distinguish from Type 1 when tests are available) |
| Ketones / DKA risk | Higher risk if untreated; DKA can be first presentation | Lower risk (can occur in some cases) | Less typical than Type 1 (can occur depending on severity/individual) |
| Typical treatment | Insulin from diagnosis | Lifestyle + oral meds; insulin sometimes needed later | Nutrition support + tailored therapy; insulin may be needed (often lower doses) |
Why type 5 diabetes is an emerging global health concern
- People with type 5 diabetes may be incorrectly diagnosed with type 1 or type 2 diabetes, leading to inappropriate treatment.
- Millions of people, particularly in low- and middle-income countries, may be living with type 5 diabetes.
- Many healthcare professionals and members of the public are still unfamiliar with this form of diabetes.
- The condition is associated with chronic undernutrition, which remains a major public health issue in many parts of the world.
Causes of type 5 diabetes
Type 5 diabetes is primarily caused by long-term undernutrition and related health factors.
Type 5 diabetes results from prolonged undernutrition, particularly during early childhood and adolescence. Poor maternal nutrition, frequent infections and chronic food insecurity can impair the development of the pancreas. This reduces its ability to produce insulin. Damage to the pancreas is not the result of autoimmune reactions, as in type 1 diabetes, or insulin resistance, as in type 2 diabetes. Instead, it is a non-autoimmune diabetes type, caused by an inability of the pancreas to produce enough insulin due to underdeveloped pancreatic tissue.
The condition highlights the impact of poverty on health outcomes, particularly in communities where people face lifelong nutritional deficits. Refugees and migrants from resource-poor settings may also be at risk, even after resettling in high-income countries.
Symptoms of type 5 diabetes
Type 5 diabetes typically appears in adolescents and young adults and may present symptoms similar to type 1 diabetes, such as:
- Weight loss
- Excessive thirst
- Frequent urination
- Fatigue
- Elevated glucose levels
However, people with type 5 diabetes often have a body mass index (BMI) below 19 kg/m² and do not show signs of autoimmune β-cell destruction, which distinguishes it from type 1 diabetes.
Who is at risk of type 5 diabetes?
- Poor maternal nutrition during pregnancy may affect foetal growth and pancreatic development.
- Nutritional deficiencies during early life may impair the pancreas’s ability to produce insulin.
- Recurrent infections during childhood can contribute to poor growth and nutritional deficiencies.
- Adults who experience prolonged periods of inadequate access to nutritious food may be at increased risk of developing type 5 diabetes.
- Refugees and migrants who have experienced prolonged nutritional deprivation may remain at increased risk, even after relocating to higher-income countries.
Prevention of type 5 diabetes
Preventing type 5 diabetes involves addressing the root causes of chronic undernutrition and health inequality. Key areas of prevention include:
- Improving maternal nutrition and reducing diabetes risk in early life.
- Strengthening child nutrition programmes.
- Ensuring food security in vulnerable regions.
- Reducing poverty and infection risk.
Early nutritional interventions and health policies that strengthen primary care access can reduce the incidence of type 5 diabetes and contribute to lowering the global diabetes burden.
Diagnosis of type 5 diabetes
Until recently, there were no standard diagnostic criteria for type 5 diabetes. As a result, many people were incorrectly diagnosed with type 1 or type 2 diabetes and received treatments that did not meet their specific needs. This led to poor outcomes and further entrenched inequalities in care.
Management of type 5 diabetes
The management of type 5 diabetes focuses on improving nutritional status and maintaining healthy blood glucose levels. Because this form of diabetes is associated with chronic undernutrition and reduced insulin production, treatment may differ from that used for type 1 or type 2 diabetes.
Management may include:
- Nutritional support to correct long-term undernutrition.
- Oral diabetes medications to stimulate insulin secretion.
- Low-dose insulin therapy, where appropriate.
Because type 5 diabetes is a newly recognised form of diabetes and research is still evolving, recommendations for diagnosis and management continue to develop. Treatment plans should therefore be individualised and guided by a healthcare professional experienced in diabetes care.
Without proper care, there is an increased risk of diabetes-related complications such as kidney disease, nerve damage and vision problems. Life expectancy may be significantly reduced if the condition is not diagnosed and treated accurately.
Type 5 Diabetes Working Group
The International Diabetes Federation has established a Working Group to develop formal diagnostic criteria to help healthcare providers distinguish type 5 diabetes from other types and to support accurate and timely treatment.
Chaired by Dr Meredith Hawkins and co-Chaired by Dr Nihal Thomas, the Working Group will also create a global patient registry to gather data, and support research and design training modules for healthcare professionals, particularly in LMICs
These efforts aim to increase awareness, reduce misdiagnosis and promote equity in diabetes care.