Type 2 diabetes is one of the fastest-growing health problems in the world. More than 400 million people are living with diabetes, and about 90% have type 2 diabetes.
The disease develops when the body cannot use insulin properly and the pancreas can no longer make enough insulin to keep blood sugar under control.
Insulin is a hormone that helps move sugar from the blood into the body’s cells, where it is used for energy. When there is not enough insulin, blood sugar stays too high. Over time, high blood sugar can damage the eyes, kidneys, nerves, heart, and blood vessels.
For many years, scientists knew that high blood sugar harms the insulin-producing beta cells in the pancreas. However, they did not fully understand exactly how this damage happened. A new study from the University of Oxford has now uncovered an important clue.
The researchers found that glucose itself may not be the main problem. Instead, the damage appears to come from substances produced when beta cells break down glucose to make energy.
After eating, carbohydrates are turned into glucose, which enters the bloodstream. Beta cells detect the rising blood sugar and release insulin, allowing the body’s cells to absorb glucose and keep blood sugar at healthy levels.
In people with type 2 diabetes, the beta cells do not disappear completely. Instead, they gradually lose their ability to release enough insulin. This means blood sugar remains high, making the disease worse over time.
The Oxford team discovered that long-term high blood sugar speeds up the way beta cells process glucose. This creates what the researchers describe as a metabolic bottleneck. As a result, certain byproducts build up inside the cells and interfere with their normal function.
These harmful byproducts, rather than glucose itself, appear to reduce the cells’ ability to produce and release insulin. This finding changes the way scientists think about why beta cells fail during type 2 diabetes.
The researchers also made another encouraging discovery. When they slowed the rate at which beta cells broke down glucose, they were able to prevent much of the damage. This suggests that future medicines could protect beta cells by targeting this process instead of simply lowering blood sugar.
Keeping blood sugar within a healthy range is essential. Blood sugar that is too low can quickly affect the brain because it depends on glucose for energy. Blood sugar that stays too high for months or years can slowly damage many organs throughout the body.
Unlike type 1 diabetes, where the immune system destroys beta cells, people with type 2 diabetes still have these cells. The problem is that the cells become less effective and release less insulin than the body needs.
The researchers say the findings could lead to new treatments that help preserve beta-cell function and slow the progression of type 2 diabetes. They also highlight the importance of healthy eating and other lifestyle habits that help control blood sugar over the long term.
The study was led by Dr. Elizabeth Haythorne and her colleagues and was published in Nature Communications.
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