In the early 1980s, human insulin produced by recombinant DNA technology cameonto the market. It was the first time that this technology had been used inmedicine, so hopes were high.
Like many physicians, I used the new human insulinin some patients under the assumption that it was a more physiologicalalternative to the animal insulins that had been in use for years.
Some of mypatients, however, reported a sudden loss of the symptoms that had previouslywarned them when their blood sugar was low. This development of hypoglycemicunawareness related to human insulin was confirmed in two clinical studies. As aresult of these findings, I believe that animal insulin is safer than humaninsulin for the ten to twenty percent of diabetic patients in whom animalinsulin produces more pronounced hypoglycemia symptoms.
Reports of the loss of low blood sugar warning symptoms led insulinmanufacturers to acknowledge the potential dangers of human insulin.Nevertheless, they soon began to withdraw bovine (cow) and porcine (pig) insulinfrom markets all over the world, while promoting the more expensive humaninsulins as a superior replacement. Diabetics had no option but to switch to thenew insulins. This led to an active movement by patients who demanded to keepporcine and bovine insulins available for those who experience a loss of warningsymptoms or other side effects from human insulin.
Now, manufacturers are withdrawing the first generation of human insulins andreplacing them with even more expensive, patent-protected insulin analogues.Patient organizations such as the International Diabetes Federation haveconcluded that "there is no overwhelming evidence to prefer one species ofinsulin over another, and patients should not be changed from one species ofinsulin to another without reason."
My fifty years of experience as adiabetologist has convinced me that the "one insulin fits all" approach is notworking. Alternative treatments – such as bovine and porcine insulin – mustremain available.