Several factors increase the risk of insulin resistance. While some of these risk factors are associated with lifestyle and can be modified, others are genetic or biochemical and therefore not modifiable.
Insulin resistance is caused by a persistently high level of insulin over a prolonged period of time that eventually causes the body's sensitivity to insulin to decrease. Some of the risk factors for insulin resistance include:
Obesity and a diet rich in fats and refined carbohydrates are factors thought to be associated with the development of insulin resistance. Abdominal fat, especially, is thought to play a role because it produces hormones that can trigger insulin resistance.
A deficiency of Vitamin D in the diet may contribute to insulin resistance due to the role it plays in glucose tolerance through its effects on insulin secretion and insulin sensitivity.
Type 2 diabetics may have increased levels of insulin. In healthy people, the action of insulin is mediated on binding to insulin receptors present on various cellular targets such as fat cells, muscle cells and liver cells.
In people with type 2 diabetes, high levels of blood sugar trigger high levels of insulin production and this leads to down regulation of the insulin receptors. This means there is a relative resistance to insulin despite the insulin levels being high. The initial cause of high blood sugar is brought about by high carbohydrate intake.
Insulin resistance is thought to be connected to inflammation. In the case of prediabetes and type 2 diabetes, the immune system releases inflammatory mediators called cytokines which are thought to disturb the action of insulin. Damage caused by free radicals or oxidative stress has also been implicated in the development of insulin resistance.
Polycystic Ovarian Syndrome (PCOS)
Diseases such as polycystic ovarian syndrome (PCOS) are associated with insulin resistance, but it is not known whether PCOS causes insulin resistance or occurs as part of the PCOS disease process. Other diseases such as Cushing's syndrome and hypogonadism have also been linked to insulin resistance.
Reviewed by Sally Robertson, BSc