Diabetes had baffled physicians for centuries when, late in the 19th century, a series of connections was made between this mysterious “sugar disease” and the pancreas, paving the way for the lifesaving insulin treatments we take for granted today.

Since then, insulin has saved millions of lives. In the United States alone, about 23.6 million people have diabetes, many of whom depend on daily insulin injections for survival.

Diabetes comes in two forms, type 1 and type 2, and robs the body of its ability to metabolize sugar. The disease has a genetic basis, but is most commonly seen with an unhealthy lifestyle, especially obesity, when it is referred to as type 2 diabetes. Type 1 diabetes usually begins in childhood or adolescence, as opposed to type 2 which usually appears in late adulthood. Symptoms of type 1 include excessive urination, weight loss, and thirst leading to drinking large amounts of water. If untreated, it can quickly lead to vomiting, coma, and death. Type 2 diabetes is most often asymptomatic, but may be associated with increased frequency of skin infections, urinary tract infections, and poor healing.

The modern understanding of diabetes began to emerge in 1869, when Paul Langerhans (1847–1888), a German biologist, first identified a part of the pancreas now called the islets of Langerhans. After his death, studies in 1889 showed that removing these islets caused laboratory animals to develop diabetes. Scientists deduced that something in the pancreas must be responsible for metabolizing sugar, and thus preventing diabetes in a healthy person. This substance was called insulin, after the part of the body where it is produced.

Replacing insulin, researchers theorized, might offer a treatment for diabetes. Efforts to isolate the substance for medical use were unsuccessful, however, until 1921, when Canadian surgeon Frederick Banting (1891–1941) and his assistant Charles Best (1899–1978) were able to inject insulin into a diabetic dog at their lab in Toronto. Subsequent insulin injections on a human subject were also a success, saving the life of a young Toronto boy who was on the verge of death.

In recognition of his accomplishment, Banting won the Nobel Prize in Physiology or Medicine in 1923 at the improbably young age of 24. He shared the honor with John Macleod (1876–1935), in whose lab Banting had performed most of his research. Banting gave half of the prize money to Best.

ADDITIONAL FACTS

  1. Diabetes is Greek for “siphon.” Ancient Greek physicians made reference to this disease, which caused sugar-laden urine, frequent urination, persistent thirst, and eventually rapid weight loss and death. Doctors used to diagnose diabetes by tasting a patient’s urine.
  2. Many unsuccessful treatments for diabetes were proposed before the discovery of insulin. One treatment involved feeding patients pieces of pancreas, hoping it would help the diseased organ.