The Confusion Around Type 5 Diabetes
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“Type 5 diabetes” is a proposed name for a rare and unclear form of diabetes linked to malnutrition. It was first seen in young, thin people in tropical countries, especially in Asia and Africa. These individuals didn’t match the typical features of type 1 or type 2 diabetes. They were not overweight, didn’t develop dangerous complications like ketoacidosis, but still needed large amounts of insulin to control their blood sugar.
This unusual pattern led doctors to think it might be a separate type of diabetes, which they called malnutrition-related diabetes mellitus (MRDM).
A Short History: Recognized, Then Removed
In 1985, the World Health Organization (WHO) officially added MRDM as a third type of diabetes. It was divided into two types:
- Fibrocalculous Pancreatic Diabetes (FCPD): With signs of pancreatic damage and abdominal pain.
- Protein-Deficient Pancreatic Diabetes (PDPD): Seen in young people without pancreatic issues but with very low body weight.
But in 1999, WHO removed MRDM from its classification. The reason? There wasn’t enough scientific proof that malnutrition alone could cause diabetes. This led to a lot of debate, especially in countries like India, where such cases were once common.
Low BMI Isn’t Always Malnutrition
One of the biggest problems in identifying MRDM is how we define malnutrition. Many early studies used BMI (Body Mass Index) as the main tool. If someone had a BMI below 19, they were called “malnourished.”
But modern research has shown this is too simplistic. In South Asia, many people have a naturally low BMI due to genetics or lifestyle. Smoking, infections, and stress can also reduce weight without real malnutrition. So, using only BMI can lead to wrong conclusions.
Experts now say that to confirm malnutrition, we should also check:
- Muscle and fat loss
- Poor food intake
- Deficiencies in vitamins and minerals
- Health problems caused by lack of nutrition
Cause or Effect? The Chicken-and-Egg Problem
Another big confusion is whether malnutrition causes diabetes, or if diabetes causes malnutrition. Uncontrolled diabetes can lead to:
- Weight loss
- Muscle breakdown
- Poor appetite
- Digestive issues
- Kidney problems
This means some people may look malnourished because their diabetes has been untreated for a long time. In fact, studies from Ethiopia and Nigeria showed many people had a normal weight before diabetes started but lost weight as the disease progressed.
So, what looks like “malnutrition-related diabetes” might actually be “diabetes-related malnutrition.”
So, Should We Call It Type 5?
Recently, some groups suggested calling MRDM “Type 5 diabetes.” But many experts disagree. Here’s why:
- There is still no clear proof that it’s a separate disease.
- BMI-based diagnosis is unreliable.
- Malnutrition and diabetes are linked in many complex ways.
- Most cases of this condition are no longer seen due to better nutrition and healthcare.
Also, types 3 and 4 diabetes are not even officially recognized. Adding a “Type 5” could create more confusion for patients, doctors, and health systems.
Final Thoughts
Malnutrition-related diabetes is a fascinating but confusing topic. While it once seemed like a separate type of diabetes, modern science shows it may not be that simple. Low BMI does not always mean malnutrition, and malnutrition does not always cause diabetes.
Before calling it “Type 5 diabetes,” we need better research, clearer definitions, and a deeper understanding of how nutrition and diabetes interact. For now, it's best to see these cases as complex forms of diabetes that need individual care, not new labels.