Diabetes Mellitus is a group of serious metabolic diseases that are increasingly affecting more and more people around the world. Despite our growing awareness and understanding of this disease, its prevalence continues to rise almost uncontrollably. In 2000, the World Health Organization estimated that at least 171 million people around the world are suffering from diabetes and according to recent projections, of all the children born in the year 2000, one in three will suffer from diabetes in their lifetime.
Within the human body, whenever carbohydrates such as bread, rice and cake are ingested, it is absorbed from the gastrointestinal tract as glucose. While glucose is a highly volatile molecule, it is also a major source of energy for our body. In particular, the brain and red blood cells amongst other body components can only utilise glucose for energy. If the blood glucose level is too low (a condition termed hypoglycaemia), one may suffer from rapid heartbeats, agitation, coma and even death. However, on the other side of the scale, if hyperglycaemia (elevated blood glucose level) occurs, one may feel tired, hyperventilation, cardiac arrhythmia and again, coma and death. Therefore, it is of utmost importance that the body's blood glucose level is strictly maintained at a stable and safe level.
Insulin is the key hormone involved in storing glucose within the body. It is produced by the beta-cells of the pancreas in response elevated blood glucose levels (such as shortly after a meal). The release of insulin activates glucose transporters on cell membranes to take glucose from the circulating blood into cells, storing it for future use. Thus, if insulin is not doing its job properly (for example, in the case of diabetes), then there will be major problems with the blood glucose levels and consequently, with the body in general.
By definition, diabetes mellitus is a "syndrome of chronic hyperglycaemia due to relative insulin deficiency, resistance or both" (Kumar & Clark. 2005). Type I diabetes (alternatively known as juvenile diabetes) is a disease that arose due to insulin deficiency. Although difficult to distinguish from type II diabetes, it is a prominent childhood disease, reaching peak prevalence at the time of puberty. However, with the current obesity epidemic increasing the risk of children getting type II diabetes, the line between the two categories is now even more blurred.
In almost all of the cases of type I diabetes, patients suffer from an immune-mediated response by their own body against the beta-cells of the pancreas. In short, the body attacks and systematically destroy the beta-cells. Without the beta-cells producing insulin, glucose is unable to be taken up into the cells, even if the blood glucose level is highly elevated. Due to the apparent lack of energy resources, patients with undiagnosed type I diabetes will initially suffer from symptoms such as hunger and fatigue. In addition, when the blood glucose level rises over the renal threshold level, it must be excreted via the kidneys. The excess glucose in the blood stream exerts hydrostatic pressures and when excreted, it holds water within the urinary system, resulting in polyuria (excess production of urine) and consequently, polydipsia (excess thirst).
Type II diabetes (or formerly referred to as adult-onset diabetes) is the more common category of the two. The four major determinants are increasing age, obesity, ethnicity and family history. In poverty-stricken countries, diabetes is a disease of the rich as they are the only ones that can afford fatty, unhealthy foods. However, in developed nations, diabetes is a disease of the poor as they can't afford to maintain a healthy diet. Genetics also play a large role as those with family background of diabetes have a larger risk of also developing diabetes.
In type II diabetes, the cause is body's growing blindness towards insulin. The pancreas is still able to produce insulin but the body is blind towards the insulin that is circulating within the blood stream. This is often due to long-term elevated blood glucose level that is caused by constant binging on an unhealthy diet combined with physical inactivity. As a result, the circulating glucose cannot be taken up by the cells. The symptoms of type II is identical to those of type I as the result is the same the body cannot utilise the glucose within the vascular system.
Overall, diabetes is a serious disease regardless which type it is or how it is caused. In order to minimise the risks of individuals developing diabetes, it is vital to understand its causes and symptoms. From what we currently know about diabetes, its causes and symptoms, it's obvious that sticking to a healthy diet alongside regular physical exercise is the key to better prevention.
References:
Kumar, P. and Clark, M. (2005) Clinical Medicine. USA: Elsevier Limited.
http://www.medicinenet.com/diabetes_mellitus /article.htm
http://en.wikipedia.org/wiki/Diabetes