MYTH: Only overweight people get type 2 diabetes, right?
The answer to this common myth is no. Let us tell you why…
As a condition that usually manifests later in life, type 2 diabetes is viewed by many as a self-inflicted disease caused by eating too much sugar and being overweight. Although obesity is strongly associated with type 2 diabetes it isn’t the only cause. In fact, many people of a healthy weight have type 2 diabetes, and similarly many overweight people do not. This is because an individual’s metabolic health can be affected by factors other than their weight.
Firstly, let’s define metabolic health; metabolic health refers to the body’s health at a cellular function, and one aspect of this is the body’s ability to utilise nutrients for energy. Within this insulin has an important function; insulin is a hormone produced by the pancreas and used by the body to regulate how glucose is used and stored. In some individuals, however, this is not the case; their pancreas may either not produce enough insulin, or may not be able to effectively use the insulin it produces, known as insulin sensitivity. High blood sugar level and type 2 diabetes is the effect of this.
Whilst obesity and lack of exercise are 2 of the most common reasons affecting metabolic state and causing type 2 diabetes, it is important to note that approximately 1 in 3 type 2 diabetics are undiagnosed. Therefore the causal factors of these individuals are not included in the statistics and therefore not accounted for in this statement. Other causal factors include family history, ethnicity, age, stress, inflammation, poor diet and visceral fat.
Let’s talk about a few of these factors…
Family history & ethnicity – Do genetics play a role?
Risk factors of type 2 diabetes includes family history and ethnicity; research(1) has found that there is a 1 in 7 risk of type 2 diabetes for children whose parents were diagnosed before the age of 50, and 1 in 2 risk for children if both parents have type 2 diabetes. Furthermore, research(2) has linked genetic mutation of the HMGA1 gene to an increased risk of type 2 diabetes in white Europeans; the study found that defects in the HMGA1 gene led to a drop in the body’s ability to make insulin receptors, thus leading to insulin resistance. In fact, 1 in 10 study participants with type 2 diabetes had a genetic mutation of the gene. Furthermore certain ethnic groups have been linked to increased risk of type 2 diabetes i.e. African Americans, Native Americans, Hispanic Americans and Asian Americans; some believe this may be due to genetics.
When the body is under stress, stress hormones such as cortisol are released. These hormones can affect the body’s blood glucose levels; for example, one of the primary functions of cortisol is to provide an immediate source of energy for the body, resulting in an increase of glucose supply to the blood. Individuals suffering chronic stress therefore have a constant production of cortisol, and chronically increased blood glucose levels as a result. This increases the risk of type 2 diabetes.
Chronic stress can lead to inflammation, which is another risk factor in the development of type 2 diabetes.
As the body’s natural response to injury, inflammation is the initial step in the healing process. Opening the blood vessels to allow free movement of the body’s natural healing substances to the affected site, it offers the body protection and fights off foreign substances such as germs and toxins. Inflammation is necessary to rid infections and heal wounds, however if the body suffers a chronic state of inflammation it can have damaging effects; chronic inflammation is caused by autoimmune conditions, allergies, chronic stress and conditions such as Crohn’s disease, and is linked to major diseases such as heart disease, arthritis and certain cancers. The link with type 2 diabetes is a result of inflammation causing insulin resistance, increasing the risk of type 2 diabetes.
Abdominal visceral fat
Abdominal visceral fat is the fat which surrounds the internal organs in the abdominal cavity. High levels of abdominal visceral fat are associated with insulin resistance and therefore, high risk of diabetes. Abdominal visceral fat can be found in individuals of all shapes and sizes, and regardless of ‘healthy’ BMI high visceral fat levels can still occur. This is because BMI doesn’t take into account muscle mass or other factors including gender and ethnicity. This presents an issue as those with a ‘healthy’ BMI may unknowingly still be at risk of diabetes. Similarly those with high muscle mass, who are determined ‘overweight’ based on BMI, may worry that they are at risk of diabetes, when in fact their weight isn’t putting them at risk. Determining levels of abdominal visceral fat is a much better indication of health than BMI.
Overall risk of type 2 diabetes is correlated with genetic, environmental and lifestyle factors. Whilst some impact more than others, it is important to recognise that there are numerous factors related to type 2 diabetes, and rid the myth that obesity and a high sugar diet high are the only causal factors.
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(1) American Diabetes Association (2014) Genetics of Diabetes. Found online at diabetes.org/diabetes-basics/genetics-of-diabetes.html
(2) Brunetti et al (2011) Functional Variants of the HMGA1 Gene and Type 2 Diabetes Mellitus. Journal of the American Medical Association (JAMA); 305 (9):903-912.