In my last blog, I talked about the blood sugar effects of carbohydrates and the resultant effect on insulin. So let’s talk about insulin today.
Insulin is secreted by special cells in your pancreas called the Islets of Langerhans. These islets are made up of beta cells. When your blood sugar goes up (actually even before your blood sugar goes up), the beta cells spit out proinsulin which gets acted upon by an enzyme that clips out a chunk called Protein C, then another enzyme ties the two ends together and voila! – we have insulin.
Insulin’s most important job is to bind to the insulin receptors on your muscle cells, sending a signal to the glucose (sugar) channels on the cell to open up and let glucose enter the cell. Without insulin, those glucose channels stay closed and the cell starts to starve and the blood sugar goes up. People with Type I diabetes don’t make insulin because their beta cells have been blitzed out, and they have to inject insulin to open their glucose channels to keep from starving to death. People with Type II diabetes have insulin; their beta cells are working; but they also have insulin resistance.
Insulin resistance happens when the insulin binds to the insulin receptor but the glucose channels do not open up. The cell is resistant to the insulin signal. It takes more insulin to bind to more receptors before the glucose channel responds. So the blood sugar (glucose) stays up, which makes the pancreas secrete more insulin — so now you have high insulin levels, too. This is the step before developing Type II diabetes but there are a lot of other bad effects of high insulin levels; they are linked to high blood pressure, heart disease, fatty liver, cholesterol problems, infertility, irregular periods, and obesity. In fact, obesity is so linked to insulin resistance that it can often not be clear which came first.
In my last blog, I talked about the increasing numbers of people with coronary heart disease and the epidemic of obesity that followed the change in recommendations to a low fat, high carbohydrate diet. So you may not be surprised to learn that there’s an epidemic in insulin resistance too. But what caused that? It’s the high levels of insulin that caused the resistance, along with the fact that in many people, the insulin level is ALWAYS elevated.
Why are people running around with elevated levels of insulin all the time? It’s because we eat all the time. We’re told it’s healthy to eat all the time. We say breakfast is the most important meal of the day, so fewer people are skipping breakfast. Then we have to have a mid-morning snack. Then we eat lunch, then there’s the afternoon snack, and then there’s dinner, and then a bedtime snack. Insulin is secreted every time we eat, and it doesn’t have time to go down before our next snack makes it go up again.
Fifty years ago, we didn’t eat that way. We had our three meals a day. We didn’t snack all the time. If you wanted an afternoon snack, Mom said: “You should have eaten more for lunch.” If you wanted a bedtime snack, Mom said: “You should have eaten more for dinner.” So between dinner and breakfast, there was a break of almost 12 hours, so insulin had time to return to normal. There actually was a fast to break, which is how “breakfast” got its name. There was time between breakfast and lunch and between lunch and dinner for insulin to return to normal too. It doesn’t have a chance now.
That’s only half of the equation though. The other part is the high-carbohydrate diet. All foods make insulin go up but carbohydrates make them go up faster and higher. Remember the description of carbohydrates as a bunch of saccharides attached to a carbon backbone that are so easy to break down into glucose that the breakdown starts in your mouth without waiting for the carbs to get to your stomach? And as I hinted earlier, when you eat carbs, your insulin goes up before the food even goes into your mouth. Your brain knows that sugar is on its way and it triggers the insulin release at the mere thought of carbs.
If you eat the typical American diet on the typical American schedule, your cells are constantly exposed to high levels of insulin. They never get a break. So they get resistant to the insulin, requiring more of it in order to open those glucose channels. Which is why one of the blood tests I order when you start a weight management plan is a fasting insulin level, to find out it you already have insulin resistance.
Insulin’s other effects, however – particularly the one that’s turning glucose into fat – aren’t inhibited at all. It’s like something out of a horror film, thinking of your body’s fat stores increasing with every minute that your insulin is elevated. Invasion of the Body Fatteners!