Diabetes is actually several medical conditions with one thing in common: they all lead to unhealthy levels of glucose in the blood. While the human body needs quick access to sugar for energy, excessive levels increase the risk of premature death from heart disease, stroke and kidney failure.
Normally, blood sugar levels are controlled by the pancreas through the release of insulin, a hormone that helps cells absorb blood sugar. But this can go wrong in several ways, reflected in the different forms of diabetes.
In the UK, around 10 per cent of cases are so-called ‘type 1’ diabetes, caused by loss of the insulin-producing cells in the pancreas. For unknown reasons, these cells are attacked by the body’s immune system, so patients need regular doses of insulin, usually by injection. But the most common type, at around 90 per cent, is ‘type 2’ diabetes, where cells no longer fully respond to insulin. This ‘insulin resistance’ leaves excess sugar in the blood, triggering demand for yet more insulin, leading to damage to the pancreas. Type 2 diabetes is often linked to diets rich in carbs and sugar, and sedentary lifestyles.
While there’s no cure for either type, patients with severe type 1 can be offered a pancreas transplant, which typically works for around five years. There are also cases of patients becoming disease-free for a while, with their pancreas mysteriously regaining its ability to produce insulin. Whether this can be triggered by drugs is currently a focus of research.
Intriguingly, a 2018 study at the University of Alabama at Birmingham, US, found that verapamil, a drug used to control blood pressure, can help type 1 diabetics maintain insulin production, but the research is still at an early stage. For those with type 2 diabetes, changing to a healthier diet, losing weight and taking more exercise can often prove effective in controlling symptoms.
Robert is a science writer and visiting professor of science at Aston University.