What is glucose?
We commonly refer to glucose as sugar, but there are actually several different types of sugar with one of them being glucose. Glucose is found in carbohydrate foods and is the primary source of energy for the cells and organs that make up our body. It can also be supplied to cells from breakdown of the body storage form called glycogen, and as a product of several metabolic reactions such as the breakdown of proteins.
What is insulin?
Insulin is a hormone that is released from an organ called the pancreas, which is located in the digestive system near the liver and behind the stomach. Insulin has many metabolic functions, but its main function is to bind to its receptors on body cell walls and allow the transport of glucose into cells for use as energy. Insulin also helps to balance your blood glucose level by signalling when glycogen formation should occur.
What is hyperglycaemia and hypoglycaemia?
Hyperglycaemia is when the level of glucose in the blood is higher than what it should be. This can occur after eating, in a fasted state, or both; and there are tests for hyperglycaemia that are used for diagnosing diabetes. Prolonged or recurrent hyperglycaemia is known to have numerous negative effects on the body, including lack of energy, dehydration, increased infection risk, headaches, and increased risk of chronic disease.
Hypoglycaemia is when the level of glucose in the blood is lower than what it should be. It usually occurs in states of impaired glucose metabolism, such as diabetes, and is uncommon in healthy individuals. Hypoglycaemia could be seen as more serious than hyperglycaemia and results in weakness, numbness, sleepiness, irritability, and possibly loss of consciousness.
What is insulin resistance?
Insulin resistance occurs when insulin binding to its receptors has reduced effects or results in incorrect communication to other cells. This causes decreased clearance of glucose from the blood causing hyperglycaemia, and increased release of insulin from the pancreas to try and compensate for chronically elevated glucose levels. This prolonged elevation of insulin levels may lead to further dysfunction in insulin signalling, availability, and function, creating a viscous cycle in our metabolism. Risk factors for insulin resistance include being overweight or obese, an inactive lifestyle, smoking, a family history of diabetes, older age, and the presence of other conditions like heart disease and polycystic ovarian syndrome.
What is diabetes?
Diabetes Mellitus is a disease which is characterised by impaired glucose metabolism. There are two types, type 1/early-onset diabetes and type 2/late-onset diabetes. In type 1 diabetes, the pancreas produces little or no insulin due to an immune system malfunction that causes immune cells to incorrectly attack the pancreas. As a result, glucose cannot enter body cells, leading to hyperglycaemia and metabolic disturbances. Type 2 diabetes usually occurs later in life when people develop insulin resistance, resulting hyperglycaemia and an increased production of insulin by the pancreas to try and compensate for this hyperglycaemia. It is mainly diagnosed in adulthood, but childhood obesity has increased its diagnostic rates in younger populations.
Notably, pre-diabetes is a state in which your blood glucose levels are higher than normal but are not high enough to be diagnosed as diabetic. This usually occurs in people with some level of insulin resistance, and they are at much higher risk of developing type 2 diabetes in the future.