Diabetes mellitus is the general name for several related metabolic disorders. Symptoms such as strong thirst and hunger and frequent urination are caused by high blood glucose levels, which arise either because the pancreas does not produce enough of the protein to control blood glucose, insulin, or because the cells that normally respond to the insulin to adjust blood glucose do not work properly. Type 1 diabetes, usually first appears in children and young adults and is caused by the pancreas not making sufficient insulin. Patients must test their blood glucose regularly and inject insulin as appropriate. Type 2 diabetes is due to insulin resistance where the insulin-receptor cells do not work properly, it might also be concomitant with insulin deficiency, it is associated with obesity and diet. Gestational diabetes can arise in pregnancy and lead to ongoing Type 2 diabetes.

Insulin is used to treat Type 1 and there are medications available too for the treatment of Type 2. If the condition is not treated it can lead to acute complications such as diabetic ketoacidosis and non-ketotic hyperosmolar coma. Serious long-term complications include heart disease, chronic kidney failure, and blindness. Estimates suggest that, worldwide, 150 million people suffer from disturbances in metabolic regulation of blood glucose, diabetes. As obesity is closely correlated with the onset of Type 2 diabetes and overweight is on the increase in many parts of the world, there is likely to be an increase in the incidence of diabetes in the coming years. More worryingly, is that childhood obesity is also on the rise and this means that a formerly adult-onset disease (Type 2) is becoming more common in youngsters.