Links of Insulin Resistance and Diabetes
Recently a patient of mine asked me a very thought-provoking question regarding the relationship between obesity and diabetes. Here is the question:
“Doc, why is it that I have diabetes and yet I am slightly overweight, whereas my friend, Mr. Sampson, does not have diabetes and his weight is over 240 lbs and a BMI of 38”?
I informed him that although there are many factors that may be responsible for developing diabetes, including genetic and environmental factors, the concept of insulin resistance and the development of diabetes is worth discussing. For the purpose of this writeup, we will be discussing the concept of insulin resistance as it relates to type 2 (aka insulin resistance) diabetes.
What is insulin and how does it relate to Type 2 Diabetes?
In general, insulin functions as a key that unlocks our cells to let in blood sugar (aka glucose) from our blood that eventually releases energy for our normal function. In type 2 diabetes, this lock-and-key process doesn't work. This loss of functionality causes glucose to build up in our blood, even when we make more insulin. The question is why is it that the insulin fails to work even though there is high sugar in our body (i.e. why is the body resistant to the insulin)? Before we try to address the reason for this lack of insulin response, let’s look at the symptoms and risks associated with this conundrum:
What are the symptoms of insulin resistance?
The problem is that no symptoms are noticed at first. One could have this condition for a long time and not know it. Sometimes, folks with severe insulin resistance get dark patches of skin on their necks, elbows, knees, hands, and armpits (if you do have this skin discoloration, please try to see your doctor for evaluation).
How do I know if I am at risk of insulin resistance?
Although being overweight is a high risk, lack of exercise, high blood pressure, or smoking may also increase your chances of developing insulin resistance that may eventually lead to type 2 diabetes. In the case of my patient who asked me about his friend who had a significantly higher BMI, the patient was both a smoker and had high blood pressure.
What are other medical issues that are associated with insulin resistance?
By far, problems with your blood system can increase the likelihood of getting insulin resistance. These include: abnormal cholesterol levels ( low HDL "good" cholesterol; high levels of LDL (bad cholesterol), triglycerides (a kind of bad fat); heart disease; a previous stroke, and blood vessel disease in your neck or legs ( your primary care doctor will evaluate you for these problems) to mention a few of them. Below are a number of medical conditions that may result from insulin resistance.
Are there genetic risk factors that lead to insulin resistance?
Generally, yes. People with an African American, Hispanic/Latino, Native American, Asian American, or a Pacific Islander ancestry are more likely to become resistant to insulin. Also, if your parent, brother, or sister has type 2 diabetes, your risk is higher. If your mother had diabetes while she was pregnant with you (gestational diabetes), your risk also goes up as well.
Is there any early diagnosis of insulin resistance?
Testing for insulin resistance is complicated, but the most common approach is for your doctor to test you for prediabetes (blood sugar that's higher than it should be). In this test, your blood sugar levels are checked when you have not eaten (also known as fasting blood sugar). Your doctor can also find your average blood sugar levels for the past couple of months ( checking A1c levels). If your blood sugar or A1c is higher than normal, this suggests insulin resistance.
If I am insulin resistant, does this mean I will develop Type 2 Diabetes?
If you make no changes to your lifestyle or control the risk factors that are mentioned above, you may become diabetic. The reason is that the high level of blood sugar forces the pancreas to keep cranking out extra insulin to try to get glucose into your body's cells. Overtime, the pancreas finally loses the battle and the cells that make insulin burn out, leading to prediabetes and type 2 diabetes. But the good news is that if you catch insulin resistance early and make changes to your lifestyle, you may stop the impending damage to the insulin-producing cells and prevent diabetes from happening.
What steps do I have to take to prevent this from happening?
One of the most cost-effective ways to prevent insulin resistance from developing into diabetes is to eat right by cutting down on sweets, refined grains and animal fats. Try to eat plenty of vegetables, fruits and whole grains and less of animal fat.
This helps to put less stress on your pancreas to constantly produce insulin in order to handle the sugars in your blood. Engaging in physical activity (at least 30 minutes of activity per day most days of the week) also help your cells to use insulin. In some cases, your doctor may want to start you on a drug called metformin to prevent or delay diabetes.
Overall, the battle of insulin resistance can be won only if you are willing to see it as a constant war and that you are ready to form a partnership with your physician and other stakeholders in the fight.
- Amalia Gastaldelli, Melania Gaggini and Ralph A. DeFronzo: Role of Adipose Tissue Insulin Resistance in the Natural History of Type 2 Diabetes: Results from the San Antonio Metabolism Study. Diabetes 2017 Apr; 66(4): 815-822.
- Malini S. Iyer et al., Denervation Reverses Hepatic Insulin Resistance Induced by High-Fat Diet. Diabetes. 2016 Nov; 65(11): 3453–3463.