Insulin is a hormone produced in the pancreas. Its purpose is to control the amount of glucose in our bloodstream, known as blood sugar. Blood sugar abides by the “Goldilocks” principle. Too much blood sugar (hyperglycemia) can damage the vessels that provide blood to vital organs. Too little blood sugar starves the brain and other vital organs of the energy and oxygen they need. So it needs to be just right…
And that's where insulin comes in. When we eat carbohydrates, they are broken down into glucose and enter the bloodstream, the speed of which is determined by whether they are simple (e.g., sugar, pasta, white rice, and processed grains), which are rapidly converted to sugar, or complex carbohydrates (e.g., vegetables and whole grains), which take longer to digest and enter the bloodstream. As blood sugar rises, the brain instructs the pancreas to release insulin, removing glucose from the blood and via receptors, depositing it in the cells, muscles, and the liver for later use, either to re-convert it into energy or store it as fat.
So, simply put, think of insulin as a traffic cop directing blood sugar into cells and organs to keep organs alive and blood sugar stable. And you can also think of it as the fat storage hormone. Nice.
Why is insulin so important?
Without the appropriate insulin response, blood sugar could rise to become dangerously high or dangerously low.
Prolonged periods of high blood sugar lead to pre-diabetes which, if left unaddressed, develops into type 2 diabetes (T2D). In the case of pre-diabetes and ultimately type 2 diabetes, the pancreas continues to release more and more insulin. However, the cells (via the insulin receptors) become “insensitive" to it. It takes more insulin to do the job. The pancreas therefore needs to work harder and harder, releasing more insulin to reduce blood sugar. This is known as insulin resistance. In the early stages of the disease, the extra insulin can eventually minimize blood sugar. Over time, the pancreas becomes too strained and unable to keep up with the ever-increasing demand for insulin, leading to type 2 diabetes. At this point, people are typically prescribed medication (such as metformin or insulin). The good news, however, is that dietary modifications can reverse pre-diabetes and reverse (put into remission) type II diabetes, avoiding the need for medication.
Contrary to type 2 diabetes, those with type 1 diabetes don't produce enough insulin, so they must inject it. They check their blood sugar often, watch what they eat, and adjust their insulin as needed. Type 1 diabetes, considered an autoimmune disease, does not yet have a cure, so a person affected with this disease must take insulin for life.
Summary: careful management of our insulin levels is paramount for good health. Eating a fiber-rich, real-food diet, devoid of added sugar, refined carbohydrates, and processed ingredients helps maintain healthy insulin responses, maintaining excellent health, especially as we age.