Type 5 Diabetes: What It Is, Causes, and Symptoms Explained

Most people are familiar with Type 1 and Type 2 diabetes. But there is a lesser-known form that has only recently received official recognition from the global medical community. Type 5 diabetes affects millions of people, particularly in low-income regions, and for decades it has been misunderstood, misdiagnosed, and undertreated. Understanding what it is, who it affects, and how it differs from other forms of diabetes is an important step towards better awareness and care.

What Is Type 5 Diabetes?

Type 5 diabetes, also known as malnutrition-related diabetes mellitus (MRDM), is a form of diabetes that develops when prolonged undernutrition during critical periods of growth prevents the pancreas from developing properly. Because the pancreas does not grow as it should, it is smaller than normal and lacks sufficient beta cells, the cells responsible for producing insulin. This results in insulin deficiency and, consequently, high blood sugar levels.

Unlike other forms of diabetes, Type 5 is not caused by an autoimmune attack on the pancreas, nor by insulin resistance linked to lifestyle factors. It is rooted in nutritional deprivation, often beginning before birth or in the earliest years of life.

The International Diabetes Federation officially recognised Type 5 diabetes in 2025. Researchers estimate that it affects between 20 and 25 million people worldwide, primarily in regions of Asia and Africa where chronic malnutrition remains widespread. Most people with Type 5 diabetes are diagnosed before the age of 30.

Why Is It Called Type 5 Diabetes?

The classification of diabetes has evolved significantly over the decades. Type 1 and Type 2 are the most widely known. Type 3c refers to diabetes arising from pancreatic disease. As researchers studied populations in lower-income countries where undernutrition is common, they identified a pattern of diabetes that did not fit neatly into any existing category.

This form, driven by diabetes due to undernutrition rather than immune dysfunction or metabolic resistance, was referred to informally as tropical diabetes or malnutrition-related diabetes mellitus for many years. The term "Type 5" reflects its formal recognition as a distinct clinical entity with its own causes, characteristics, and treatment needs.

Giving it an official classification matters. It means researchers can now pursue dedicated studies, healthcare providers can apply appropriate diagnostic criteria, and the millions of people living with this condition can receive care that actually addresses the root cause.

How Type 5 Diabetes Differs From Type 1 and Type 2

Who Is at Risk of Type 5 Diabetes?

Type 5 diabetes primarily affects people whose early development was shaped by poverty and food insecurity.

• Individuals born in low- and middle-income countries where chronic undernutrition is widespread, particularly in parts of South Asia and sub-Saharan Africa
• People who experienced malnutrition during fetal development, meaning their mothers had inadequate nutrition during pregnancy
• Those who suffered protein-energy malnutrition during infancy, early childhood, or adolescence, when the pancreas is still growing
• Young adults, typically under 30, who present with diabetes but are underweight and have a history of nutritional deprivation
• Communities with limited access to diverse, nutrient-rich foods, clean water, or healthcare
• Individuals in regions where dietary staples such as unrefined cassava are consumed in large quantities with inadequate protein intake, as this combination may expose the pancreas to harmful levels of cyanide compounds
• People who have experienced intestinal parasites or repeated infections during childhood, both of which worsen nutritional status and may affect pancreatic development

Causes of Type 5 Diabetes

The fundamental cause of Type 5 diabetes is sustained nutritional inadequacy during the periods when the pancreas is growing and maturing. Several specific mechanisms have been identified.

Protein and Calorie Deficiency

Chronic shortage of dietary protein and energy during fetal development, infancy, or early childhood reduces the growth and function of the pancreas. With fewer beta cells, the pancreas cannot produce adequate insulin, leading to insulin deficiency malnutrition as a driving force behind high blood sugar.

Reduced Beta Cell Mass

Undernutrition during critical developmental windows impairs the growth of insulin-producing beta cells. The result is a physically smaller pancreas with a significantly reduced capacity to produce and secrete insulin throughout life.

Cyanide Toxicity From Dietary Staples

In some regions, particularly in parts of Africa, populations rely heavily on unprocessed cassava as a dietary staple. When consumed without adequate protein, the body struggles to detoxify cyanogenic compounds in cassava, leading to accumulation of cyanide radicals that are toxic to pancreatic cells. This is thought to contribute to a specific subtype sometimes referred to as tropical diabetes.

Environmental and Infectious Factors

Repeated intestinal parasitic infections and lack of access to safe drinking water worsen nutritional status over time. These environmental factors compound the effects of poor diet on organ development, including the pancreas.

Fetal Origins of Pancreatic Development

When a mother experiences significant nutritional deprivation during pregnancy, it can affect the development of the baby's pancreas in utero. This early programming effect means that insulin deficiency may be set in motion even before birth.

Symptoms of Type 5 Diabetes

Because many symptoms of Type 5 diabetes overlap with the general signs of undernutrition, the condition is frequently missed or attributed to simple weakness or poverty-related health problems.

Common Diabetes Symptoms

• Increased thirst and dry mouth
• Frequent urination
• Fatigue and severe exhaustion
• Blurred vision
• Headaches
• Slow-healing cuts and wounds
• Recurrent infections due to reduced immunity

Signs That Suggest Type 5 Specifically

• Significant and unexplained weight loss with a very low BMI, typically below 18.5
• Visible signs of long-term undernutrition such as stunted skeletal growth or delayed puberty in younger individuals
• Enlarged parotid glands, the salivary glands located near the jaw, a feature seen in chronic malnutrition
• Changes to skin texture or hair, which can indicate prolonged nutritional deficiency
• Absence of ketones in the urine at diagnosis, which distinguishes it from Type 1 diabetes

If you or someone you care for is young, noticeably underweight, lives in or has a history in a region with food insecurity, and shows these symptoms, it is important to seek medical advice and ensure the possibility of Type 5 diabetes is considered.

How Type 5 Diabetes Is Diagnosed

Diagnosing Type 5 diabetes can be challenging, particularly because it closely resembles Type 1 diabetes in some respects. Both tend to affect younger individuals and both involve significant insulin deficiency. However, there are important distinguishing features.

The starting point is a blood glucose test, which checks the level of sugar in the blood. A result of 200 mg/dL or higher is generally consistent with a diabetes diagnosis.

Key Features That Point to Type 5

• Age of onset younger than 30 years
• Underweight status with a BMI below 18.5
• A documented history of childhood malnutrition or food insecurity
• Absence of ketones in the urine at the time of diagnosis, unlike the typical presentation of Type 1 diabetes
• Absence of autoantibodies associated with Type 1 diabetes, which can be confirmed through an antibody panel where testing is available

Supporting Tests

• An HbA1c test, which reflects average blood sugar levels over the past two to three months, helps confirm the severity of glucose dysregulation and provides a baseline for monitoring treatment
• Urinalysis to check for ketones and assess kidney function
• Nutritional blood tests to evaluate protein levels, micronutrient deficiencies, and overall metabolic status

In many low-income settings, access to the full range of diagnostic tests is limited, which is why clinical history, body weight, and the absence of ketones remain particularly important diagnostic indicators.

Treatment Options for Type 5 Diabetes

Treatment for Type 5 diabetes must address both the high blood sugar and the underlying nutritional deficiency. Managing one without the other is insufficient.

Insulin Therapy

Because the underdeveloped pancreas cannot produce adequate insulin, insulin injections are the primary medical treatment for Type 5 diabetes. A healthcare provider will determine the appropriate dose and regimen based on individual needs. Researchers are currently studying whether oral diabetes medications may offer an effective alternative or complementary option in the future.

Nutritional Rehabilitation

Improving nutritional status is central to managing Type 5 diabetes. Increasing protein and calorie intake through food and, where necessary, therapeutic nutritional support helps address the root cause. Protein in particular is essential for tissue repair, immune function, and supporting what remains of pancreatic function.

Micronutrient Supplementation

Prolonged undernutrition often leads to deficiencies in essential vitamins and minerals. Supplementation with iron, zinc, B vitamins, and fat-soluble vitamins may be recommended alongside dietary improvements.

Treating Concurrent Infections

Intestinal parasites, recurrent bacterial infections, and other conditions that worsen nutritional absorption must be identified and treated. Addressing these underlying infections is part of improving overall health and supporting better nutritional status.

Ongoing Monitoring

Regular blood sugar monitoring and follow-up care are important to assess how well treatment is working and to adjust insulin doses as the individual's nutritional status and pancreatic function evolve.

How It Impacts Long-Term Health

Despite being caused by malnutrition rather than autoimmunity or lifestyle factors, Type 5 diabetes carries the same long-term risks as other forms of diabetes when blood sugar remains poorly controlled over time.

People with Type 5 diabetes are at risk of developing cardiovascular disease, including heart disease and stroke. Kidney damage from persistent hyperglycaemia can progress to chronic kidney disease. Damage to the blood vessels in the retina can lead to vision problems and, without intervention, blindness. Nerve damage can cause pain, numbness, and weakness in the limbs.

The compounding burden of undernutrition, limited healthcare access, and now diabetes-related complications means that people with Type 5 diabetes face significant health challenges that extend well beyond blood sugar management. Early recognition, adequate nutrition, and consistent medical follow-up are the most important factors in reducing the long-term impact of this condition.

Prevention and Nutritional Management

While Type 5 diabetes cannot always be prevented once nutritional damage has occurred during development, there is significant scope for reducing its risk at a population level and managing its effects at an individual level.

• Ensure adequate protein and calorie intake throughout pregnancy to support healthy fetal pancreatic development
• Prioritise diverse, nutrient-rich foods during infancy and early childhood, when the pancreas and other organs are developing rapidly
• Address childhood malnutrition early through nutritional programmes and access to a varied diet
• Reduce reliance on unprocessed cassava as the sole dietary staple in regions where it is associated with Type 5 diabetes, and ensure protein intake is sufficient to support safe detoxification
• Access clean, safe drinking water and treat intestinal parasites and infections promptly to preserve nutritional absorption
• For those already diagnosed, follow a structured dietary plan with adequate protein, complex carbohydrates, healthy fats, and micronutrient-rich foods
• Eat regular, balanced meals and avoid prolonged periods without food, as blood sugar regulation is already compromised
• Where accessible, work with a dietitian to build a personalised nutrition plan that supports both blood sugar management and overall recovery from undernutrition
• Attend regular health checks and blood tests to monitor glucose levels, nutritional markers, and organ health

When to See a Doctor

If you are young, underweight, and experiencing symptoms such as unusual fatigue, frequent thirst, frequent urination, or slow-healing wounds, particularly if you have a background of food insecurity or malnutrition, it is important to see a doctor. These symptoms may point to Type 5 diabetes, which requires a diagnosis and treatment plan tailored specifically to your needs.

Early medical attention matters because unmanaged high blood sugar causes progressive damage to the kidneys, eyes, heart, and nerves, and these changes are largely irreversible once established. The sooner a diagnosis is made, the sooner treatment can begin.

If you have already been diagnosed with Type 1 diabetes but are underweight with no history of ketones at diagnosis, it is worth discussing with your doctor whether Type 5 diabetes may be a more accurate diagnosis. Correct classification leads to more appropriate care.

Key Takeaways

• Type 5 diabetes is a newly recognised form of diabetes caused by chronic undernutrition during critical periods of growth, resulting in an underdeveloped pancreas with insufficient insulin-producing capacity
• It was officially recognised by the International Diabetes Federation in 2025 and is estimated to affect 20 to 25 million people globally
• It is distinct from Type 1 diabetes (autoimmune) and Type 2 diabetes (insulin resistance), and is most common in regions where food insecurity and poverty are widespread
• Key distinguishing features include young age of onset, very low BMI, history of malnutrition, and absence of ketones in the urine at diagnosis
• Treatment requires both insulin therapy and nutritional rehabilitation to address the root cause
• It carries the same long-term complications as other types of diabetes if blood sugar is not managed consistently
• Prevention focuses on adequate maternal and childhood nutrition during the developmental years

Staying Proactive About Your Health

Diabetes in any form requires ongoing attention and monitoring. Whether you are managing a recent diagnosis, supporting a loved one, or simply staying informed about your health, regular testing plays a crucial role in understanding how your body is responding over time.

Keeping track of key health markers through routine blood tests, including glucose levels, HbA1c test results, kidney function, and nutritional indicators, gives you and your healthcare team the information needed to make timely decisions and adjust care as needed.

Metropolis Healthcare offers over 4,000 tests, including comprehensive diabetes monitoring panels and nutritional health assessments. With home sample collection available across a wide network of touchpoints, getting tested is convenient and accessible. Book easily through the website, app, call, or WhatsApp, and trust your results to NABL and CAP-accredited laboratories with quick turnaround times.

Taking a proactive approach to your health, through regular check-ups, informed conversations with your doctor, and timely testing, is one of the most meaningful steps you can take for your long-term wellbeing.

Frequently Asked Questions

Is Type 5 Diabetes Officially Recognised?

Yes. The International Diabetes Federation officially recognised Type 5 diabetes in 2025, making it a formally classified type of diabetes distinct from Type 1, Type 2, and other forms. For many years, it was known under various names including malnutrition-related diabetes mellitus and tropical diabetes. Its recognition marks an important step towards dedicated research, accurate diagnosis, and appropriate treatment for the millions affected.

What Causes Type 5 Diabetes?

Type 5 diabetes is caused by prolonged nutritional deficiency, particularly a lack of protein and calories, during fetal development, infancy, or early childhood. This prevents the pancreas from developing properly, resulting in a smaller organ with fewer beta cells and reduced capacity to produce insulin. In some regions, chronic exposure to cyanide compounds from unprocessed cassava, combined with inadequate protein intake, may also contribute to pancreatic damage.

How Is Type 5 Diabetes Different From Type 2 Diabetes?

Type 2 diabetes develops when the body becomes resistant to insulin and cannot produce enough to compensate. It is strongly associated with overweight, obesity, sedentary lifestyle, and family history. Type 5 diabetes, in contrast, is caused by undernutrition impairing pancreatic development. People with Type 5 are typically underweight, young, and have a history of food insecurity. There is no insulin resistance involved. The two conditions require different treatment approaches, and misclassifying Type 5 as Type 2 can lead to ineffective care.

Is Type 5 Diabetes Caused by Malnutrition?

Yes, entirely. Malnutrition is the defining cause of Type 5 diabetes. Specifically, it is chronic protein-energy undernutrition during the developmental years that prevents the pancreas from growing and functioning properly. This is why Type 5 diabetes due to undernutrition is concentrated in regions where poverty and food insecurity are most severe. It is not caused by poor lifestyle choices or autoimmune processes.

Can Type 5 Diabetes Be Prevented?

To a significant extent, yes. Because it is rooted in malnutrition, improving nutritional access and quality during pregnancy and early childhood directly reduces the risk of Type 5 diabetes developing. Ensuring adequate protein and calorie intake during fetal development and the early years of life, treating childhood infections and parasites that impair nutrition, and providing access to diverse, balanced diets are all effective preventive strategies. At a broader level, addressing food insecurity and poverty are fundamental to preventing this condition.

Is Type 5 Diabetes Reversible?

The underlying pancreatic underdevelopment caused by early malnutrition is not fully reversible. The pancreas that did not develop adequate beta cell mass cannot regenerate completely. However, nutritional rehabilitation can improve overall health and support whatever remaining pancreatic function exists. With insulin therapy and improved nutrition, people with Type 5 diabetes can achieve meaningful glucose control and significantly reduce their risk of long-term complications. Ongoing research may reveal new treatment possibilities in the future.

Who Is Most Affected by Type 5 Diabetes?

Type 5 diabetes predominantly affects young people under the age of 30 in low- and middle-income countries where chronic malnutrition is prevalent, particularly in parts of South Asia and sub-Saharan Africa. People who were undernourished during fetal development or early childhood are most at risk. Because it shares some features with Type 1 diabetes, it is frequently misdiagnosed, which means many people in affected regions may not be receiving the appropriate treatment.

References

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