What is diabetes?
You have probably heard the word diabetes over and over again, and you have a vague idea of what it means. If you want a clearer understanding of what diabetes is, what causes it, and its different forms, you are in the right place.
Diabetes is a fairly common disease, with about 422 million people living with it worldwide. It is also quite serious, causing about 1.5 million deaths annually.1
It is a lifetime condition that makes your blood sugar (blood glucose) dangerously high. This happens when the hormone that keeps blood sugar under control (insulin) is either:
- too little or completely absent; or
- insulin is present but cannot be used.
Insulin is produced by the pancreas, an organ found in our abdomen (tummy), behind the stomach. A special group of cells inside the pancreas called beta cells are responsible for insulin production.
Our bodies get sugar from the food we eat. Glucose is the form of sugar that the cells in our bodies use to carry out their functions - think of it as the fuel for our cell’s engines. These cells, in turn, are surrounded by blood. Glucose is normally released into the blood and it needs insulin to help it get into certain cells. Insulin opens the door for glucose, so to speak.
Without insulin, glucose is unable to get into these cells and remains in the blood. Persistently high levels of blood glucose can lead to complications of diabetes.
The main forms of diabetes are:
- Type 1 diabetes
- Type 2 diabetes
Obesity and diabetes
Type 1 diabetes
This is an autoimmune disease where the pancreas is attacked by cells of the immune system which erroneously recognize it as a threat to the body. The pancreas, therefore, produces smaller and smaller amounts of insulin as it is progressively damaged, until it becomes completely unable to produce it.2
Type 1 diabetes is therefore described as a state of absolute insulin deficiency. The cells are bathed in glucose which they have no access to. Imagine your car swimming in a pool of fuel but with your (empty) gas tank closed. None of the fuel is able to get into your tank and so your car cannot work. This is exactly what happens with glucose and your cells in type 1 diabetes.2
Although people with type 1 diabetes could also be obese, obesity has not been found to be a strong risk factor for the condition. Autoimmune destruction of the cells of the pancreas which produce insulin is the main process responsible for type 1 diabetes.3
Type 2 diabetes
This is caused by a combination of reduced insulin release from the pancreas and a decreased sensitivity of cells to insulin.4
Persistently high levels of blood sugar and fats which are seen in obesity affect the pancreas and decrease its ability to release insulin in response to high glucose levels. Additionally, the cells that need insulin to ‘open up their doors for glucose entry’ become unable to use insulin. This means that the available insulin is unable to get glucose into these cells - insulin resistance.4,5
Obesity and low levels of physical activity are therefore strong risk factors for the development of type 2 diabetes. This form of diabetes is consequently diagnosed most frequently in adulthood (in persons 40 years or older).6,7,8
Obesity and insulin resistance
There’s a strong correlation between obesity and insulin resistance. In obesity, fat cells known as adipocytes, release substances that contribute significantly to insulin resistance. Fat accumulation around the upper body - central obesity - is more strongly associated with insulin resistance than lower body fat accumulation.4
In the early stages of insulin resistance, the pancreas tries to compensate by producing more insulin. The resulting large amounts of insulin in the blood are able to overcome insulin resistance to a certain extent. Over time, however, the pancreas is not able to keep up with the high insulin demand, it becomes burnt out and insulin levels decrease - leading to high blood sugar and diabetes.4
Prediabetes is a state where the blood sugar is high enough to be above normal, but not high enough to warrant a diagnosis of diabetes. It often progresses to full-blown diabetes if nothing is done about it.
More information and support for prediabetes can be found here. If you would like to know more about type 1 diabetes, please click here. And if you want help and support for type 2 diabetes, click here.
Diabetes is a chronic condition which is characterized by high levels of blood glucose. There are 2 main types of diabetes, although disease symptoms are similar for both types. Obesity plays a major role in causing type 2 diabetes, while autoimmune destruction of the pancreas is mostly responsible for type 1 diabetes. Both forms of the disease require good blood sugar control to prevent disease complications.
- Diabetes [Internet]. [cited 2022 Sep 27]. Available from: https://www.who.int/health-topics/diabetes
- Saberzadeh-Ardestani B, Karamzadeh, Basiri M, Hajizadeh-Saffar E, Farhadi A, Shapiro AJ, et al. Type 1 Diabetes Mellitus: Cellular and Molecular Pathophysiology at A Glance. Cell Journal [Internet]. 2018;20(3):294–301. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6004986/
- Corbin KD, Driscoll KA, Pratley RE, Smith SR, Maahs DM, Mayer-Davis EJ, et al. Obesity in type 1 diabetes: pathophysiology, clinical impact, and mechanisms. Endocrine Reviews [Internet]. 2018 Oct 1 [cited 2022 Nov 13];39(5):629–63. Available from: https://academic.oup.com/edrv/article/39/5/629/5060447
- Galicia-Garcia U, Benito-Vicente A, Jebari S, Larrea-Sebal A, Siddiqi H, Uribe KB, et al. Pathophysiology of type 2 diabetes mellitus. International Journal of Molecular Sciences [Internet]. 2020 Jan [cited 2022 Sep 27];21(17):6275. Available from: https://www.mdpi.com/1422-0067/21/17/6275
- Kaku K. Pathophysiology of Type 2 Diabetes and Its Treatment Policy. Japan medical association journal [Internet]. 53(1):41–6. Available from: https://www1.med.or.jp/english/journal/pdf/2010_01/041_046.pdf
- Sullivan PW, Morrato EH, Ghushchyan V, Wyatt HR, Hill JO. Obesity, inactivity, and the prevalence of diabetes and diabetes-related cardiovascular comorbidities in the u. S., 2000–2002. Diabetes Care [Internet]. 2005 Jul 1 [cited 2022 Nov 13];28(7):1599–603. Available from: https://diabetesjournals.org/care/article/28/7/1599/27992/Obesity-Inactivity-and-the-Prevalence-of-Diabetes
- Abdullah A, Stoelwinder J, Shortreed S, Wolfe R, Stevenson C, Walls H, et al. The duration of obesity and the risk of type 2 diabetes. Public Health Nutrition [Internet]. 2011 Jan [cited 2022 Sep 27];14(1):119–26. Available from: https://www.cambridge.org/core/journals/public-health-nutrition/article/duration-of-obesity-and-the-risk-of-type-2-diabetes/
- Li S, Zhao JH, Luan J, Langenberg C, Luben RN, Khaw KT, et al. Genetic predisposition to obesity leads to increased risk of type 2 diabetes. Diabetologia [Internet]. 2011 Apr [cited 2022 Nov 13];54(4):776–82. Available from: http://link.springer.com/10.1007/s00125-011-2044-5