In 1915, type 1 diabetes mellitus was an extremely serious diagnosis, often associated with a dire prognosis. Patients—especially children—suffered from debilitating symptoms such as unquenchable thirst, frequent urination, and constant hunger, all of which drastically reduced quality of life. Before the discovery of insulin, treatment options were extremely limited and relied mainly on extremely strict diets and prolonged fasting—strategies that only temporarily slowed the inevitable progression of the disease. A century after that pivotal breakthrough, it is important to understand and reflect on the challenges and hardships faced by those living with diabetes in a time without effective treatments.
Type 1 and Type 2 Diabetes Mellitus
The earliest records concerning diabetes date back to the Ebers Papyrus, around 1550 BCE, which describes a condition characterized by excessive urine production. The term “diabetes” comes from the Greek diabainein, meaning “to pass through,” referring to the excessive loss of body fluids. In the 17th century, Thomas Willis introduced the term “mellitus” (from the Latin mellitus, meaning “honey”) after observing that patients’ urine had a sweet taste, due to the high concentration of glucose. At the time, urine analysis was a fundamental diagnostic tool: physicians assessed its color, odor, density, and often even tasted small amounts to confirm the presence of glucose—a practice that helped distinguish diabetes mellitus from other forms of polyuria. However, understanding the pathophysiology of diabetes remained limited until the 19th century. In 1869, Paul Langerhans identified clusters of cells in the pancreas—now known as the islets of Langerhans—responsible for producing insulin, the hormone that regulates blood glucose levels by promoting its uptake by cells for energy use. Later, in 1889, Joseph von Mering and Oskar Minkowski demonstrated that removing the pancreas in laboratory animals induced diabetes, paving the way for the discovery of insulin. Eventually, diabetes was classified into two categories: Type 1 and Type 2 Diabetes Mellitus.
Type 1 diabetes is an autoimmune disease in which the immune system destroys the Langerhans cells, impairing insulin production. The insulin deficiency prevents cells from using glucose, leading to an accumulation of sugar in the blood. In contrast, Type 2 diabetes—more common and often associated with factors such as obesity and a sedentary lifestyle—occurs when the pancreas still produces insulin, but the body becomes resistant to its effects. Cells become less responsive to the hormone, reducing glucose absorption. Initially, the pancreas compensates by increasing insulin secretion, but over time this ability diminishes, resulting in chronic hyperglycemia. From a therapeutic perspective, insulin administration is essential for patients with Type 1 diabetes, as their bodies cannot produce it. For those with Type 2 diabetes, various strategies are employed, including lifestyle modifications, diet, physical activity, and hypoglycemic medications aimed at improving insulin sensitivity or reducing hepatic glucose production, supplemented by insulin therapy when necessary.
Understanding Blood Glucose Levels: What’s Normal, What’s Not
Effective diabetes management requires a clear understanding of blood glucose values and how they relate to clinical conditions. In healthy individuals:
° Fasting blood glucose typically ranges from 70 to 99 mg/dL (3.9–5.5 mmol/L).
° Postprandial levels (measured 2 hours after a meal) should remain below 140 mg/dL (7.8 mmol/L).
In diabetic patients or at-risk individuals:
° Hyperglycemia is defined as fasting levels above 126 mg/dL (7.0 mmol/L) or postprandial levels above 180 mg/dL (10.0 mmol/L). Chronic hyperglycemia increases the risk of complications affecting the eyes, kidneys, nerves, and cardiovascular system.
° Hypoglycemia, conversely, occurs when blood glucose drops below 70 mg/dL (3.9 mmol/L), with severe symptoms often appearing below 54 mg/dL (3.0 mmol/L). If untreated, it can lead to confusion, seizures, or even loss of consciousness.
° In diabetic ketoacidosis (DKA), a serious complication of type 1 diabetes, blood sugar levels often exceed 250 mg/dL (13.9 mmol/L) and are accompanied by ketone accumulation and metabolic acidosis.
These reference ranges are essential not only for diagnosis but also for guiding treatment decisions and preventing life-threatening emergencies.
The Starvation Diet: An Extreme Therapy
In the early 20th century, in the absence of effective treatments, doctors resorted to the so-called “starvation diet.” American physician Frederick Allen prescribed a severely hypocaloric regimen—fewer than 500 calories a day, with virtually no carbohydrate intake.
The goal of fasting and caloric restriction was to slow the progression of diabetes, but the cost in terms of quality of life was extremely high: patients, often in states of severe emaciation and weakness, suffered unrelenting hunger and frequently died from malnutrition or metabolic complications within a few months.
This approach was especially tragic for children, who made up the majority of type 1 diabetes cases. Families watched helplessly as their children slowly declined, while medical staff could offer only palliative support and comfort.
Leonard Thompson: The First Clinical Success
A turning point in the history of diabetes occurred in 1921, when Frederick Banting and Charles Best, at the University of Toronto, succeeded in isolating insulin—the pancreatic hormone essential for glucose metabolism and blood sugar regulation.
The first patient treated with insulin was Leonard Thompson, a 14-year-old Canadian boy with advanced type 1 diabetes, hospitalized in critical condition due to severe diabetic ketoacidosis (DKA). This life-threatening condition is characterized by marked hyperglycemia (typically >250 mg/dL), metabolic acidosis (blood pH <7.3, bicarbonates <15 mEq/L), and the presence of ketone bodies in blood and urine.
Ketoacidosis occurs when absolute insulin deficiency prevents cells from using glucose as an energy source. In response, the body initiates lipolysis—the breakdown of triglycerides in fat tissue—releasing free fatty acids. These are converted in the liver into ketone bodies—mainly acetoacetate, β-hydroxybutyrate, and acetone—which can be used for energy but, in excess, dangerously acidify the blood.
The first injection administered to Leonard Thompson, made from a crude pancreatic extract, caused a severe allergic reaction, likely due to protein impurities. After a purification process by biochemist James Collip, a second insulin injection led to rapid and marked improvement: blood sugar levels dropped, ketone production ceased, and the acidosis gradually resolved.
Leonard Thompson lived for another 13 years with diabetes, becoming the symbol of the first clinical success of insulin therapy. This event marked the beginning of a new era in medical history, transforming a once-lethal disease into a manageable chronic condition.
Complex Clinical Cases
Leonard Thompson’s story was not unique. Elizabeth Hughes, daughter of U.S. Secretary of State Charles Evans Hughes, was diagnosed with diabetes in 1919 at age 11. Subjected to the harsh “starvation diet,” her body weight fell to just 20 kg. She was among the first patients treated with insulin in Toronto and lived until 1981.
However, thousands of children never had access to this revolutionary therapy. Before the introduction of insulin, the course of type 1 diabetes was relentlessly fatal. Patients suffered from severe metabolic dysfunction, profound cachexia—a clinical syndrome marked by extreme weight loss, muscle and fat depletion, deep fatigue, and general deterioration—alongside dehydration, eye complications such as blindness, and extremely high infant mortality. Healthcare workers faced daily tragic cases with no effective treatments to alter the disease’s outcome.
The Evolution of Insulin Therapy
Since its initial extraction from bovine and porcine pancreases, insulin therapy has undergone significant advancement. In the 1930s and ’40s, long-acting formulations were introduced. In the 1970s, the first recombinant human insulins were developed through genetic engineering. The launch of biosynthetic insulin production in 1982 marked another major milestone that further revolutionized diabetes treatment.
Today, insulin therapy benefits from advanced technologies, including:
° Pre-filled insulin pens for easier and more accurate dosing;
° Insulin pumps for continuous delivery;
° Real-time glucose sensors for constant blood sugar monitoring;
° Automated systems, often referred to as “artificial pancreases,” capable of adjusting insulin delivery autonomously.
These innovations have made diabetes management more precise, personalized, and less invasive, significantly improving patients’ quality of life.
The Crucial Role of the School Nurse
Daily diabetes management—especially in children—requires specialized knowledge and ongoing support. In this context, and referring to present-day realities, the school nurse plays a fundamental role. This professional ensures diabetes self-management education, regular blood sugar monitoring, and timely insulin administration. They are also essential for responding to hypoglycemic or hyperglycemic emergencies, while promoting a safe and inclusive school environment for students with diabetes.
Unfortunately, in Italy, school nurses are not yet widely present in educational institutions, leaving many families to face the complexities of diabetes management during school hours alone. This very issue was the focus of my graduation thesis, in which I thoroughly analyzed the role of the school nurse in caring for children with type 1 diabetes mellitus, highlighting their critical importance for students’ safety and well-being in mandatory education settings.
Global Inequities in Insulin Access
Despite extraordinary progress in research and insulin delivery technologies, equitable and continuous access to this essential drug remains a significant global challenge. In low- and middle-income countries, the cost of insulin and the tools required for its administration can be a substantial barrier, hindering effective diabetes management.
Even in high-income settings, such as the United States, high costs can still limit access and adherence to treatment for portions of the population.
This reality raises pressing ethical and public health concerns, especially when considering the original intent of insulin’s discoverers: Frederick Banting and his colleagues chose to sell the insulin patent for a symbolic sum, believing their discovery should be universally accessible to all patients, regardless of socioeconomic status.
Historical Continuity and Commitment to Global Equity
The discovery of insulin was one of the greatest revolutions in modern medical history, transforming a once-terminal diagnosis into a manageable condition. Over a century later, this breakthrough continues to save lives every day.
Honoring its value means not only remembering its historical impact but also ensuring insulin is universally recognized and guaranteed for what it truly is: a life-saving medication. In this context, healthcare professionals—especially nurses—are called to a dual responsibility: to provide competent and compassionate care and to actively advocate for equitable access to treatment, especially where economic or systemic barriers persist.
Making insulin accessible, safe, and sustainable is not just a public health priority—it is a shared ethical responsibility that gives real meaning to the legacy left by Banting, Best, and the pioneers of diabetology.
References 📚
Bliss, M. (2007). The discovery of insulin. University of Chicago Press. Cooper, T., & Ainsberg, A. (2010).
Breakthrough: Elizabeth Hughes, the discovery of insulin, and the making of a medical miracle. St. Martin’s Press. Katzenberger, L. (2022). It belongs to the world: Frederick Banting and the discovery of insulin. Albert Whitman & Co.
American Diabetes Association. (2022). Classification and diagnosis of diabetes: Standards of medical care in diabetes — 2022. Diabetes Care, 45(Suppl 1), S17–S38. https://doi.org/10.2337/dc22-S002 Chen, D., Lu, H., Ma, Y., et al. (2023).
Definition, classification and diagnosis of diabetes mellitus. Frontiers in Nutrition, 10, 1116051. https://doi.org/10.3389/fnut.2023.1116051
MedlinePlus. (2022). Blood sugar monitoring. Retrieved from https://medlineplus.gov/ency/patientinstructions/000086.htm
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