Insulin is a hormone made by your pancreas.
It allows your cells to use glucose (sugar) for energy.
Insulin resistance is the name given to
when cells of the body don’t respond properly to the hormone insulin. Insulin
resistance is the driving factor that leads to type 2 diabetes, gestational diabetes
and prediabetes.
The body produces insulin when glucose
starts to be released into the bloodstream from the digestion of carbohydrates
in the diet. Normally this insulin response triggers glucose being taken into
body cells, to be used for energy, and inhibits the body from using fat for
energy. The concentration of glucose in the blood decreases as a result,
staying within the normal range even when a large amount of carbohydrates is
consumed. When the body produces insulin under conditions of insulin
resistance, the cells are resistant to the insulin and are unable to use it as
effectively, leading to high blood sugar. Beta cells in the pancreas
subsequently increase their production of insulin, further contributing to a
high blood insulin level. This often remains undetected and can contribute to
the development of type 2 diabetes or latent autoimmune diabetes of adults.
Although this type of chronic insulin resistance is harmful, during acute
illness it is actually a well-evolved protective mechanism. Recent
investigations have revealed that insulin resistance helps to conserve the
brain's glucose supply by preventing muscles from taking up excessive glucose.
In theory, insulin resistance should even be strengthened under harsh metabolic
conditions such as pregnancy, during which the expanding fetal brain demands
more glucose.
People who develop type 2 diabetes usually
pass through earlier stages of insulin resistance and prediabetes, although
those often go undiagnosed. Insulin resistance is a syndrome (a set of signs
and symptoms) resulting from reduced insulin activity; it is also part of a
larger constellation of symptoms called the metabolic syndrome.
Insulin resistance may also develop in
patients who have recently experienced abdominal or bariatric procedures. This
acute form of insulin resistance that may result post-operatively tends to
increase over the short term, with sensitivity to insulin typically returning
to patients after about five days.
