Diabetes begins with having a little more sugar in your blood than normal. Early on, something begins to block the control panel that allows the insulin key to unlock the door that lets the glucose transfer from the blood into the cell. As time passes, there is more resistance at that cell door, resulting in not allowing the insulin to work properly.
The important factor to understand is that the real problem is the resistance to allowing the insulin to enter the cell. This is called, simply enough, insulin resistance. It takes more and more of the insulin keys to get the door unlocked. At first, everything seems okay. The pancreas produces more insulin to make up for the problem of that extra glucose. However, eventually the pancreas can’t make enough extra insulin to take care of the excess glucose that can’t get into the cells. That’s when blood work shows your glucose is elevated and your doctor informs you that you have diabetes.
Insulin resistance has three causes that by now should be sounding familiar to you as we seek to understand diabetes. See if you fit into any one of the three categories. If so, then you need to pay extra attention to an article from Public Health Nutrition, which points out that the three causes of insulin resistance are inactivity, improper diet, and overweight.
Here’s what the study found, in each category, about people who were insulin resistant but not yet labeled diabetic.
Exercise. Insulin resistance was lessened in those who undertook vigorous exercise and not in those who elected to be sedentary.
Diet. A high saturated fat intake was associated with higher insulin levels, higher glucose levels, higher insulin resistance, and higher risk of developing type 2 diabetes.
Diet. Poly and monounsaturated fat foods showed a lower risk of type 2 diabetes, lower glucose numbers, and lower insulin resistance.
Diet. A low intake of dietary fiber significantly increased the risk of type 2 diabetes. Researchers concluded that fiber reduces insulin resistance.
Weight loss. Weight is determined by what someone eats and whether they exercise. The authors of this report cite a study where the individuals who ate properly and exercised reduced their risk of diabetes by 58 percent over the people in the study who did not eat properly and exercise.
Studies like this put diabetes and insulin resistance into proper perspective. When I read them, I look closely at the summary of their significant findings. Here’s the conclusion this study reached: “Weight loss achieved by an increase in physical activity and dietary change including reduction in total and saturated fat and increased dietary fiber can reduce the incidence of diabetes.”
Understanding insulin resistance is the first step to understanding the primary problems that lead up to and cause full-blown diabetes. Diabetes is primarily a disease that centers on insulin resistance rather than insulin deficiency.
The problem isn’t just too much glucose in the blood; it’s the resistance of the cells of the body to letting insulin work as a key to open the cell door to let that glucose into the cell. We can measure the amount of glucose in our blood and see it is elevated, but the real culprit is that the insulin key doesn’t work properly to unlock the cell door to allow the glucose to transfer from the bloodstream into the cell.
What Causes Insulin Resistance?
The question is this: What causes this resistance?
An article published in Biochemical Journal helps explain what exactly causes the lock on the cell door to swell, which then keeps the insulin key from functioning properly. Researchers studied individuals with different fat deposits and found an inflammatory response in the ones who had what is called visceral adipose tissue. This is the fat around your mid-abdomen, and it’s prominent in people who have that fatty apron inside the front mid-part of their belly. Not to get too deep into the specifics, but what I think is good to learn from this study is that increased inflammation within anyone’s body exists if extra fatty tissue is present.
This study reported that inflammation is the potential link between fatty tissue and insulin resistance. Researchers also showed that certain products produced by the fat tissue could cause an inflammatory response in the cells where insulin was trying to get glucose in. If you think of inflammation similar to taking sandpaper and rubbing it on the palm of your hand until it becomes reddened and begins to swell, you can imagine what a similar reaction could be on the walls of the cells insulin is trying to work in. Their study was complex in identifying the exact particles that adipose tissue produced that caused inflammation and increased resistance to insulin, but the study concluded that obesity-associated insulin resistance is related to inflammation as indicated by the accumulation of those specific particles.
An article published in the New England Journal of Medicine takes us a little deeper into how excess fat tissue is related to insulin resistance. I won’t go too far into medical detail, but just enough for you to gain an understanding. Researchers showed that the normal glucose-insulin mechanism takes place mainly in muscle cells and liver cells. Normally, glucose goes from the blood into the cells and is stored there as glycogen, which can be broken back down into glucose as the body runs out of the normal amount of glucose in the blood. Whenever blood glucose becomes low and the body needs more for fuel, the stored glycogen breaks down into glucose and is used.
The study again pointed out that the beta cells in the pancreas produce the insulin that drives the glucose in the blood to enter the cells. But they also pointed out that, with diabetes, the early problem is that the cells become resistant to the insulin and more and more insulin must be produced. Researchers stressed that the primary reason the glucose level goes up is because of “insulin resistance” of that pathway into the cells. Only later does it become evident that the beta cells of the pancreas can’t produce enough insulin to get the excess sugar into enough cells for the body to function. Their comment was that “insulin resistance predates beta-cell dysfunction.”
Insulin resistance plays the key role in causing diabetes. Knowing that most of the action happens in muscle cells and liver cells makes it easier to understand how fatty tissue in these two locations can affect how insulin works and how extra fat can cause insulin resistance at these two locations. Basically, the study showed that as extra fat tissue accumulates in muscle and the liver, there is more resistance to insulin being able to work properly. It’s as though the extra fat tissue within the cells acts like a “cut-off” switch that prevents insulin from unlocking the door properly.
Yes, the study showed that extra fat tissue is a cause of insulin resistance, but the most significant and exciting finding is what happens to insulin resistance if you lose weight. Their main conclusion showed that insulin resistance is reversed after weight loss.
Their study had one more significant finding, involving a subgroup of individuals who exercised. Researchers found them to have even better results in improving insulin resistance.
The final takeaway of the study is that combining weight loss with exercise “is clearly the preferred medical therapy.”
Hopefully, the insights from these studies not only help you understand the danger of extra fatty tissue in your body but also encourage you to work to get every extra clump of adipose tissue out of your system, whether it’s where you can see it in your mid-gut or hidden within your liver and muscles.
This study focused on the cause of insulin resistance, but its conclusion could have been summarized in four words of advice to diabetics: lose weight and exercise.
Insulin Resistance: A Review
Hopefully, you’re beginning to understand the steps toward developing diabetes, and insulin resistance is the initial step. Most people with insulin resistance don’t realize they have it. It is silent, causing no symptoms, and then one day they can be diagnosed as diabetic.
When I was in medical school, I realized I needed to go over my notes from each day’s lecture at least three times to retain the knowledge. A quick review now is that, initially, something prevents the insulin from being able to transfer the glucose from your bloodstream into the cell. That leaves excess glucose in your blood, but the body sensors just tell your pancreas to put out more insulin, which it does. The extra sugar finally gets into the cells because of the extra insulin, but as the insulin resistance gets a little worse, your body must produce more insulin, and finally, even the extra insulin is unable to get the excess glucose moved into the cells.
At this point, your lab report shows your blood sugar is a little above normal but not high enough to be labeled diabetic. As time goes on, the pancreas produces all the insulin it can, but it isn’t enough to keep the glucose level below the level when your doctor tells you you’re diabetic.
An article in Current Molecular Pharmacology points out that insulin resistance is associated with overeating and inactivity. More importantly, the researchers quoted in the article tied being overweight with heart disease, saying, “Cardiovascular diseases are basically twins of obesity.” That says it well. If you are overweight or obese, and are inactive as well, you’re setting yourself up for heart failure—a heart attack, bypass surgery, or stents.
An article in the New England Journal of Medicine states it best: “Insulin resistance is present in most of the 69% of American adults who are overweight or obese.” Extra fat plays a significant role in the mechanism that blocks the lock on the door of the cells. Having excess weight is an initial step in developing diabetes, and it also plays a role in a combination of other problems related to diabetes. These include the effect on our cholesterol, with low levels of the “hero” HDL cholesterol and an elevation of the “lethal” LDL cholesterol, as well as an increase in high blood pressure.
If we want those locks on the cell doors to be sensitive to the insulin key when it attempts to unlock the door to allow glucose into the cells, we need to banish excess weight.
Defeating Insulin Resistance
Now that we understand the role insulin resistance plays in the cause and progression of diabetes, it’s even more important to learn how to combat this hidden factor most people don’t realize about diabetes. Let’s look at something you can do to wipe out the cause of the problem, because it’s a consistent problem throughout all stages of diabetes.
Getting rid of excess adipose tissue is your initial step in fighting insulin resistance, but that’s intertwined with another lifestyle change: combining exercise with weight loss. This is the very best strategy for decreasing insulin resistance.
Let’s review another study that takes us one step further toward proving the significance of exercise in decreasing insulin resistance. This study was published in the journal Diabetes Care, and I know it will encourage you to exercise as you also change your eating habits to lose weight.
Researchers wanted to see if intense exercise improved insulin resistance more than lighter exercise. They studied two groups. One group worked on weight loss with diet alone, and the other group worked on weight loss with diet plus intense exercise. Researchers wanted to see if more aggressive lifestyle intervention is more beneficial. They based the intensity of the exercise on how rapid the participants’ heartbeats were as they exercised twenty to thirty minutes a day at least five days a week. They set the intensity level above the 80 percent level of maximum heart rate. The formula used to figure the 80th percentile heart rate is to take the number 220 and subtract the person’s age. That gives the maximum heart rate. Taking 80 percent of that result gives the goal they used in measuring the intensity of exercise.
Insulin sensitivity changed significantly in the intensive exercise group. If you count your pulse as you exercise, you may find that if you haven’t exercised in the past, a brisk walk will get your pulse to the 80th percentile. As your heart muscle gets stronger, you will need to increase your walk to a slow trot to get there. The same principle applies to bike riding, swimming, elliptical training, or using a treadmill. I encourage you to consult with your doctor to see if you have any limitations for exercise, and then begin your personal workout.
Weight loss and exercise are the two essentials in combating insulin resistance and diabetes. Exercise is the number one tool in losing weight, but your diet is a coworker. The journal Diabetologia reported which factors could improve insulin sensitivity so the cells would accept glucose more easily. Their focus was on the foods eaten by diabetics, and their comment was that insulin sensitivity “improved with the diet rich in polyunsaturated fatty acids compared with the diet rich in saturated fatty acids.” That simply means the saturated fat found in red meat, cheese, cream, butter, and fried foods should be avoided and the good polyunsaturated fat found in fish, nuts, olive oil, and avocado should be eaten instead.
A study reported in Lancet summed it up: unless you develop a healthy lifestyle, your insulin resistance—and diabetes—will worsen.
Running out of insulin is not the cause of diabetes; it’s the result of diabetes.