Insulin – Function and Importance

Insulin was the first hormone identified in 1920s, which won the doctor and medical student who discovered it the Nobel Prize (Banting and Best).


Insulin is a hormone produced by the pancreas that regulates the level of glucose, a simple sugar that provides energy, in the blood. The human body requires a steady amount of glucose throughout the day and that glucose comes from the foods that we eat.


The pancreas lies at the back of the abdomen behind the stomach and has two main functions:

To produce juices that flow into the digestive system to help us digest food

To produce the hormone called insulin. 


Insulin is the key hormone that controls the flow of glucose (sugar) in and out of the cells of the body. Carbohydrates (or sugars) are absorbed from the intestines into the bloodstream after a meal. Insulin is then secreted by the pancreas in response to this detected increase in blood sugar. Most cells of the body have insulin receptors which bind the insulin which is in the circulation.  When a cell has insulin attached to its surface, the cell activates other receptors designed to absorb glucose (sugar) from the blood stream into the inside of the cell.


The role of insulin can be categorised as follows:


Insulin is central to regulating carbohydrate and fat metabolism in the body

Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle

Insulin stops the use of fat as an energy source by inhibiting the release of glucagon

As its level is a central metabolic control mechanism, its status is also used as a control signal to other body systems (such as amino acid uptake by body cells

Insulin also influences other body functions, such as vascular compliance and cognition. Once insulin enters the human brain, it enhances learning and memory and in particular benefits verbal memory.



Diabetes -Type I and Type II- Explanation and basic treamtnet

Diabetes mellitus, often simply referred to as diabetes is a group of metabolic diseases in which a person has high blood sugar either because the body does not produce enough insulin or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger).


The full name ‘diabetes mellitus’ is derived from the Greek word ‘diabetes’ which means siphon and the Latin word ‘mellitus’ which means honeyed. This is because the excess sugar is not only found in the blood but it may also appear in the urine.
The two main types of diabetes are:




Type 1 diabetes formally known as Insulin Dependent Diabetes Mellitus (IDDM) or ‘juvenile diabetes’  is a form of diabetes that results from autoimmune destruction of insulin-producing beta cells of the pancreas. The subsequent lack of insulin leads to increased blood and urine glucose. Type I diabetes can range from mild to more severe forms and it does require medical treatment. While it cannot be cured, it can be managed and many diabetics live healthy, normal lives.


Type I diabetes is often caused by an autoimmune attack in which the immune system actually assaults the pancreas causing permanent damage. The body may also be unable to use insulin properly. Since insulin helps the body to absorb glucose safely, a lack of insulin or inability to use it can be very dangerous.


Type I diabetes can develop at any age but usually appears before the age of 40 and especially in childhood. It accounts for between 5% and 15% of all people with diabetes.


The onset of Type I diabetes is often sudden and it appears to be related to genetic factors and disease which means that it is not preventable through diet and exercise. Treatment need not significantly impair normal activities if sufficient patient training, awareness, appropriate care, discipline in testing and dosing of insulin is taken.


Type I diabetes is insulin dependent which means that the patient will need to take insulin supplement usually in the form of injections to stay healthy. Injection is the most common method of administering insulin but insulin pumps and inhaled insulin have been available at various times.




Type II diabetes formally known as Non Insulin Dependent Diabetes Mellitus (NIDDM) or ‘adult onset’ diabetes is a metabolic disorder that is characterised by high blood glucose in the context of insulin resistance and relative insulin deficiency.


Type II diabetes develops when the body either cannot make enough insulin or when the insulin that is produced does not work properly (known as insulin resistance). Insulin acts as a key to unlocking the cells and so if there isn’t enough insulin or if it isn’t working properly, the cells will only partially absorb energy resulting in glucose build-up in the blood.


Type II diabetes usually appears in people over the age of 40 though in South Asian and black communities, it often appears from the age of 25. It accounts for between 85% and 95% of all people with diabetes.


Management of type II diabetes focuses on lifestyle interventions (i.e. regular exercise), lowering other cardiovascular risk factors (i.e. losing weight) and maintaining blood glucose levels in the normal range (i.e. eating a healthy diet).


Basic treatment requires the patient to adhere to the following guidelines:

  • Monitor weight and blood pressure on regular basis
  • Quit smoking to keep arteries and circulation healthy
  • Monitor the amount of cholesterol in the blood
  • Consume a healthy balanced diet with fibre and carbohydrates
  • Avoid fatty, sugary and fried junk food
  • Consume complex carbohydrates instead of simple carbohydrates