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Pre-Diabetes and Insulin Resistance

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Insulin Resistance and Pre-Diabetes
The Link Between Diabetes, Obesity and Heart Disease

By Nina Nazor

What is insulin resistance?

Insulin resistance occurs when our fat, muscle and liver tissues cannot respond adequately to insulin because they are less sensitive to its action. They resist the action of insulin. Lets see what it means.

The cells in those tissues have insulin receptors in their surface. When insulin binds to these receptors it triggers a reaction that allows glucose to enter into the cells to be stored or converted into energy. In other words, when insulin molecules bind with insulin receptors, this unlocks and opens the door allowing glucose molecules to enter.

Glucose is transported from the surface into the cells through the cell membrane by especial molecules called glucose transporters.

In insulin resistance, those insulin receptors are not binding insulin adequately. Therefore, the body thinks there is insufficient insulin and sends a signal to the pancreas in order to increase insulin production.

As the pancreas releases more insulin, this causes what is called hyperinsulinemia, or an excessive amount of insulin in blood.

What is the metabolic syndrome?

Insulin resistance produces a cascade of metabolic problems which can lead to the development of hypertension, heart disease and diabetes. This represents the metabolic syndrome, formerly known as Syndrome X.

The metabolic syndrome is comprised by high levels of insulin in blood, high blood pressure, high triglycerides, low good cholesterol (HDL), high bad cholesterol (LDL) and high blood glucose levels.

What is pre-diabetes?

Pre-diabetes occurs when blood glucose levels are higher than normal but not yet high enough to be diagnosed as diabetes. You can think of it as "early diabetes". Usually a person with pre-diabetes has some degree of insulin resistance.

It is believed that people with pre-diabetes develop type 2 diabetes within 10 years. Pre-diabetes also raises the risk of heart disease. But the good news is that losing 10% of your body weight and exercising for at least 45 minutes every day can help prevent or delay the development of type 2 diabetes.

What is the relationship between obesity and insulin resistance?

There is another important factor related to insulin resistance and the metabolic syndrome: abdominal obesity.

It seems that when a person has a lot of fat in the abdominal area, this fat releases a great amount of fatty acids (the smallest units of fat) to the portal circulation, which leads directly to the liver.

When the liver receives all those fatty acids from the abdominal area, it tries to get rid of them by making more lipoproteins, the vehicles that transport fat and cholesterol to the arteries and other tissues.

All this causes good cholesterol (HDL) to decrease, bad cholesterol (LDL) to increase and higher levels of tryglycerides. The consequence is cholesterol plaque in the arteries. This also seems to be related with the development of hypertension.

Who is at risk of developing the metabolic syndrome?

The main risk factors for developing this syndrome are the following (and the more factors one has, the higher the risk):

•  To be overweight: a Body Mass Index (BMI) higher than 25 kg/m2 or a waist circumference of more than 40 inches for men and more than 35 inches for women
•  To have a sedentary lifestyle
•  To be older than 40 years
•  To be Latino/Hispanic American, African American, Native American, Asian American or Pacific Islander
•  To have family history of type 2 diabetes, hypertension or cardiovascular disease
•  To have a history of glucose intolerance or gestational diabetes
•  To have hypertension, high tryglycerides/low HDL-cholesterol, or cardiovascular disease
•  To have Acanthosis nigricans -a dark rash in the body folds
•  To have Polycystic ovary syndrome

How can I find out if I have the metabolic syndrome?

If you have some of the following indicators you might have the metabolic syndrome and/or pre-diabetes:

•  Fasting glucose between 110-125 mg/dL
•  Blood glucose levels 2 hours after a glucose tolerance test higher than 140 mg/dL
•  Triglycerides higher than 150 mg/dL
•  LDL cholesterol -bad cholesterol- higher than 100 mg/dL
•  Blood pressure higher than 130/85 mm Hg

6 tips to reduce insulin resistance

1. At least 45 minutes of daily exercise, like brisk walking or jogging. Exercise helps insulin receptors to work better, reduces blood glucose levels, decreases bad cholesterol (LDL), raises good cholesterol (HDL) and improves blood pressure readings.
2. Reduce your intake of saturated fats, trans fats, cholesterol and sugars.
3. Avoid extremes in carbs or fat intake.
4. Reduce bad cholesterol (LDL) and triglycerides and increase good cholesterol (HDL) levels.
5. Control hypertension
6. Take your medications as prescribed. Some medications are very useful to help insulin receptors work adequately.

Source: Melvin R, Siden MD, Vryan F, Understanding the links between insulin resistance, diabetes and cardiovascular diseases. Practical diabetology, 24(2)2-15. June 2005