How High Blood Sugar Affects Your Cholesterol Level

Insulin resistance is the driver

A diabetic testing his blood sugar.
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A high level of glucose (sugar) in the bloodstream is associated with a host of complications, including cholesterol abnormalities. The linking factor: insulin resistance—when cells no longer respond appropriately to the hormone insulin. As a result, a person may develop an abnormal cholesterol profile—low high-density lipoprotein (HDL, or "good cholesterol"), high low-density lipoprotein (LDL, or "bad cholesterol"), and high triglycerides.

These cholesterol abnormalities then increase a person's risk for heart disease and stroke. With this in mind, managing your pre-diabetes or diabetes is about more than just keeping your blood sugar in check. It's also about working to protect your cardiovascular health.

Insulin Resistance and Cholesterol Changes

After eating a meal, carbohydrates are broken down into glucose by your digestive system. This glucose is then absorbed through the wall of your intestines into your bloodstream.

Once there, insulin—a hormone, made by your pancreas, that is the primary regulator of carbohydrate metabolism—brings glucose into various cells, so they have the energy to function and do their jobs. Insulin also blocks the breakdown of fat into fatty acids (lipolysis) within your body.

Insulin resistance is when the cells become less responsive to this process. As a result, blood sugar eventually increases, which is why it's considered a precursor to pre-diabetes and type 2 diabetes.

Fats are also broken down within the body at an increased rate, and this ultimately leads to various cholesterol changes. Specifically, insulin resistance lowers HDL and raises triglycerides and LDL.

A low HDL level or a high LDL level paired with a high triglyceride level is linked to the buildup of plaque (fatty deposits) in the walls of arteries. This condition is called atherosclerosis and it increases your risk of developing a heart attack and stroke.

Metabolic Syndrome

Metabolic syndrome is not a specific disease or condition, even though its name suggests that. Rather, it's a collection of circumstances that increase a person's chances of developing type 2 diabetes and heart disease.

This phenomenon is often preceded by insulin resistance and can essentially be considered a possible "next stop" in terms of elevated risk to your cardiac health stemming from high glucose levels.

The National Cholesterol Education Program defines metabolic syndrome as having three or more of the following characteristics:

  • Abdominal obesity, defined as a waist size greater than 40 inches in men and 35 inches in women
  • Triglycerides greater than or equal to 150 milligrams per deciliter (mg/dL) or on medication for high triglycerides
  • HDL levels less than 40mg/dL in men or less than 50mg/dL in women or on medication for low HDL
  • Blood pressure greater than or equal to 130/85 millimeters of mercury (mmHg) or on medication for high blood pressure
  • Fasting blood glucose level greater than or equal to 100mg/dL or on medication for high blood glucose

In order to treat metabolic syndrome and, specifically, prevent the development of type 2 diabetes and/or heart disease, the following is necessary:

  • Lose weight: A 5% reduction in body weight is linked with improvement in cholesterol profile, glucose levels, and insulin resistance.
  • Exercise: Work out at a moderate intensity (e.g., brisk walking, dancing, or water aerobics) for at least 30 minutes daily.
  • Adhere to a healthy diet: The Mediterranean diet is commonly recommended and is rich in fruits, vegetables, nuts, whole grains, and olive oil.
  • Quit smoking
  • Reduce blood pressure: With lifestyle changes and medication (if needed), the goal is blood pressure that is less than 130/80.
  • Reduce cholesterol: With lifestyle changes and medication (if needed), the goal is an LDL that is less than 80 to 100mg/dL.
  • Improve blood sugar control: This is done through lifestyle changes and medication (definitely if you have diabetes; possibly if you have prediabetes)

There are currently no medications to treat high blood sugar from insulin resistance that are approved by the U.S. Food and Drug Administration (FDA). That said, research has found that taking metformin (a medication that lowers blood sugar) may prevent the onset of type 2 diabetes.

When to See Your Doctor

If you haven't gone in yet for your yearly health check-up, or if you are experiencing potential symptoms of high blood sugar (e.g., urinating a lot, feeling unusually thirsty, and/or having blurred vision), it's important to make an appointment with your internist or family physician.

Most people with high blood sugar and insulin resistance have no symptoms, which is why regular screening with your doctor is important.

Your doctor can perform blood tests, such as a fasting blood sugar test or a hemoglobin A1C test, to check for pre-diabetes and diabetes. He can also order a lipid panel to check your blood cholesterol levels, in addition to checking your blood pressure and weight.

Based on your doctor's assessment and laboratory results, together you can come up with a plan to ultimately reduce your risk of having a heart attack or stroke.

A Word From Verywell

The take-home message here is that insulin resistance increases your risk for both high glucose levels and abnormal cholesterol levels, which then increases your risk for heart disease. So, whether you have one or more features of metabolic syndrome, are simply worried about your well-being, or perhaps missed your annual physical, be sure to see your doctor. Easy and straightforward measurements and blood tests can help you get to the bottom of your health.

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