BY AMY CAMPBELL, MS, RD, LDN, CDCES | JUNE 7,
If you’ve watched television lately, you might have seen ads for supplements and diet plans claiming to reverse insulin resistance and help you lose weight. The term “insulin resistance” has been trending in the media for a while now, and it might be hard to figure out what it is, what it means if you have it, and what to do about it. If you have questions about insulin resistance, keep reading to get answers.
What does insulin do?
It’s hard to grasp insulin resistance unless you know what insulin is. If you have diabetes, you likely know that insulin is a hormone that is made by the pancreas by special cells called beta cells. Insulin’s job is to lower blood glucose (sugar) levels by moving that glucose from the blood into the cells in your muscles, fat stores, and liver, where it’s used for energy.
When you eat food, glucose levels in the blood go up. The pancreas senses this and releases insulin into the blood; the insulin then lowers blood glucose to keep it in a normal (safe) range. Of course, this is assuming that your pancreas makes enough, or any, insulin to help control blood glucose levels — but more on that in a moment.
If insulin levels are low, the liver is alerted to release stored glucose so that energy is always available, even if you haven’t eaten for a while.
What does “insulin resistance” mean?
It’s pretty amazing what the body does to help regulate blood glucose levels and provide fuel for bodily processes. Unfortunately, things can go awry with this finely tuned system. Here’s what may happen, as explained by the CDC (Centers for Disease Control and Prevention):
- A lot of glucose enters the bloodstream.
- The pancreas has to work overtime to pump out more insulin to move that glucose into cells.
- Over time, the cells stop responding to the surge of insulin — in other words, they’ve become “resistant.”
- The pancreas responds by making even more insulin to help the cells respond.
- Eventually, the pancreas tires out and just can’t keep up with the demand.
- The end results? Blood sugar levels continue to go higher and higher.
When there is too much glucose or sugar in the blood it can be very damaging to the body. Also, the high levels of insulin signal the liver and muscles to try and store the excess sugar. Eventually, they get full, so the liver sends the excess sugar to fat cells to be stored as … you guessed it, body fat. That means weight gain. Now the stage is set for prediabetes and type 2 diabetes.
What’s the link between insulin resistance and prediabetes?
If not stopped in its tracks, insulin resistance can lead to prediabetes. Prediabetes means that blood sugar levels are higher than normal but not high enough to be considered diabetes (and we’re talking type 2 diabetes). Prediabetes usually occurs in people who have some level of insulin resistance or whose beta cells aren’t making enough insulin. Over time, if insulin resistance continues and/or there just isn’t enough insulin around, prediabetes can develop into type 2 diabetes.
Why does insulin resistance happen in the first place?
Researchers aren’t exactly sure what causes insulin resistance or prediabetes, but two major factors are excess body weight and a lack of physical activity.
Obesity, especially too much fat in the abdomen (belly fat) and around organs is a main cause of insulin resistance. This fat, called visceral fat, makes hormones and other substances that cause inflammation in the body. It’s this inflammation that plays a role in insulin resistance, type 2 diabetes, and also, heart disease. Insulin resistance can also lead to fatty liver disease. However, you don’t have to be overweight or obese to have insulin resistance: even people at a “normal” weight can have insulin resistance, as they may have excess visceral fat in the stomach area.
If you lead a pretty sedentary lifestyle, your risk for getting insulin resistance is higher than someone who is regularly active. When you get enough physical activity, it can lead to changes in the body that helps to keep glucose levels in balance; plus, you’re less likely to have an excess amount of visceral fat, as well.
Are there other risk factors for insulin resistance?
For sure, and they happen to be the same risk factors for prediabetes and type 2 diabetes. So, besides excess body weight and a lack of physical activity, these factors can raise your risk of insulin resistance:
- A family history of type 2 diabetes
- A history of gestational diabetes
- Being age 45 or older
- High blood pressure
- High cholesterol
- Smoking
- Sleep problems
- Excess alcohol intake
Other hormone conditions, such as Cushing’s syndrome, acromegaly, and hypothyroidism (low thyroid) can increase the risk of insulin resistance.
How do you know if you have insulin resistance?
Unlike some other health conditions, it’s not always easy to tell if you have insulin resistance because there usually aren’t any symptoms unless diabetes develops. Some people develop a skin condition called acanthosis nigricans, which is darkened skin in the armpits or on the back and sides of the neck. Small growths called skin tags can also develop in these areas.
While blood sugar levels are not high enough to cause symptoms for most people with insulin resistance, some studies show that people with prediabetes may have early changes in their eyes that can lead to retinopathy, which is an eye condition that typically affects people who have diabetes.
How does insulin resistance affect the body?
Insulin resistance can lead to weight gain, which, in turn, can worsen insulin resistance and lead to prediabetes or type 2 diabetes.
Being insulin resistance also raises the risk of what is called metabolic syndrome. Metabolic syndrome is a group of conditions that raise the risk of not just diabetes, but also heart disease and stroke. The markers of metabolic syndrome include:
- A large waistline due to excess fat in the stomach area
- High blood sugar
- High blood pressure
- High triglycerides, or blood fat
- Low HDL (good) cholesterol
About one in three adults in the U.S. have metabolic syndrome, according to the National Heart, Lung, and Blood Institute.
Can people with type 1 diabetes have insulin resistance?
The answer is a resounding “yes.” While the American Diabetes Association points out that insulin resistance isn’t a cause of type 1 diabetes, some people with type 1 diabetes may be genetically predisposed to becoming insulin resistant, or they may be overweight. And a person with type 1 diabetes who is insulin resistant “will need higher insulin doses to keep their blood sugar under control” compared with those who are more insulin sensitive.
How is insulin resistance diagnosed?
There isn’t a routine test for insulin resistance, but your health care provider should assess your medical and family history, do a physical exam, ask about signs and symptoms, and do blood tests. Typically, your provider will check your glucose level (either fasting or with a glucose tolerance test); they may also check a hemoglobin A1C and a lipid panel that includes cholesterol and triglycerides. Glucose and A1C tests can indicate if you have prediabetes or possibly even type 2 diabetes.
Can insulin resistance be prevented or reversed?
In order to make your cells more insulin “sensitive” (the opposite of “resistant”), the following lifestyle changes can help prevent insulin resistance as well as possibly reverse it:
- Losing 5-7% of your weight
- Being physically active most days of the week
- Eating better, which means cutting back on refined carb foods, and eating more whole foods, which includes vegetables, fruits, whole grains, lean meats, and healthy fats
- Getting enough and better-quality sleep
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