Some considerable time before a person is diagnosed with either pre-diabetes or type 2 diabetes, changes in the body that are associated with those conditions can occur. One significant change is the development of insulin resistance.
In this article, we take a look at what insulin does, what insulin resistance is and what its consequences can be.
What is insulin?
Insulin is a hormone that is produced by the pancreas. It enables glucose in the blood to move into cells in muscles where it’s used for energy. By doing that, it regulates the level of blood glucose.
Insulin is secreted when blood glucose rises, typically during and after a meal, when the carbohydrates eaten is broken down into glucose. Once insulin has done its job, any excess glucose is converted to glycogen for storage in liver and muscle tissues.
What is insulin resistance?
Insulin resistance occurs when the muscles and liver do not respond effectively to the hormone. The body starts to produce more insulin in an attempt to stabilise glucose levels, and keeps doing so until the pancreas is exhausted, resulting in too much glucose circulating in the blood.
Insulin resistance causes various reactions in the body.
- In fatty tissue, it causes the breakdown of triglycerides (the main type of fat in the body), which leads to elevated fat levels in the blood. High triglyceride levels can increase your risk of heart disease, heart attack and stroke.
- In the liver, insulin resistance prevents effective glucose storage, leaving more glucose to circulate in the bloodstream. It may also lead to fatty liver, a condition that can impair the organ’s function.
- In muscle tissue, insulin resistance reduces the absorption of glucose, again causing higher blood glucose levels.
The exact cause of insulin resistance is not known. While there are few insulin resistance symptoms, some people with the condition develop a skin condition known as acanthosis nigricans, which appears as dark patches on the neck, groin and armpits.
What is pre-diabetes?
A person with pre-diabetes has higher than recommended blood glucose levels. You may be diagnosed with pre-diabetes if your:
- fasting blood glucose levels are between 6.1 and 6.9 mmol/L and;
- less than 11.1 mmol/L for a two-hour glucose tolerance test.
Pre-diabetes rarely has signs or symptoms. It is most commonly diagnosed when a person has a fasting glucose, Hba1c or glucose tolerance test (GTT).
Pre-diabetes has the same risk factors as type 2 diabetes. Some of these can be changed (are modifiable) and others cannot (are non-modifiable).
Modifiable risk factors include:
- excess body fat
- having a waist measurement that is greater than 80 cm for women and 94 cm for men
- being physically inactive
- having high levels of triglycerides and low levels of HDL-C (‘good’ cholesterol)
- having high blood pressure
- smoking.
Non-modifiable risk factors include:
- having a close relative such as a parent or brother/sister with type 2 diabetes
- having an ethnic background of Aboriginal and Torres Strait Islander, Pacific Islander, South-East Asian, Asian (the sub-continent), Middle-Eastern or North African
- age–although diabetes can develop at any age, the risk of pre-diabetes increases after the age of 35
- having Polycystic Ovarian Syndrome (PCOS)
- having had diabetes in pregnancy (gestational diabetes) or given birth to a big baby (more than 4.5 kg).
People with pre-diabetes have between 10 and 20 times greater a risk of developing type 2 diabetes.
What is type 2 diabetes?
Type 2 diabetes affects how your body uses glucose for energy. This happens either because it is not producing enough insulin or because it is not able to use the hormone effectively. Type 2 diabetes develops over a long period of time, so early screening and diagnosis can be very beneficial.
In some cases, the onset of type 2 diabetes can be prevented or delayed by adopting sustainable healthy habits. These include:
- managing your weight
- doing regular physical activity
- eating healthy and nutritious foods
- managing blood pressure
- managing cholesterol levels
- not smoking.
The symptoms of type 2 diabetes usually show when blood glucose levels have been high for some time. They include:
- frequently needing to urinate
- increased thirst
- tiredness
- feeling hungry
- having cuts that heal slowly.
Prevention and treatment
As mentioned above, it is possible to manage pre-diabetes and prevent or delay type 2 diabetes by adopting sustainable healthy habits such as doing regular physical activity and eating healthily.
A healthy diet includes eating a wide variety of nutritious foods from the five food groups below.
- Fruits
- Vegetables
- Grains—includes foods made from wheat, rice, oats, cornmeal, barley or other cereal grains.
- Protein—includes lean meat, poultry, seafood, beans and peas, eggs, nuts and seeds
- Dairy—includes low-fat milk, yoghurt, cheese and fortified soy milk.
The Australian Dietary Guidelines and the Australian Guide to Healthy Eating provide more information and advice about healthy eating.
Exercise can be very beneficial for people with pre-diabetes. It can reduce insulin resistance, lower blood glucose levels and enhance joint and muscle movement. Regular exercise can help maintain a healthy weight, lower blood pressure and reduce the risk of heart disease. It also benefits mental health by reducing stress and improving sleep.
The Australian Government guidelines recommend that adults do at least 30 minutes of moderate intensity physical activity most days. Moderate intensity exercise is any activity that causes your heart to beat faster and makes you breathe harder. Examples are:
- Swimming
- cycling
- brisk walking
- tennis
- gardening.
Alternatively, you could do three short bursts of 10–15 minutes of activity.
It’s also beneficial to do muscle-strengthening exercise (also known as resistance training) on at least two days per week. This could include:
- lifting weights
- doing vigorous gardening activities such as digging.
Don’t forget to speak to your doctor before starting any new type of physical activity. If you’re not used to doing exercise, start gently.
Conclusion
Research shows that type 2 diabetes can be prevented in up to 58% of cases of pre-diabetes. It’s important to act quickly—the sooner you start, the sooner your risk level will decrease.
The Life! program can help you make a positive start.
Life! is a free healthy lifestyle program that helps you improve your eating habits, increase your physical activity and manage stress. The program is for people who are at risk of developing type 2 diabetes, heart disease and stroke.
Life! is run by experienced health professionals, including dietitians and exercise physiologists, who guide and support you to make healthy lifestyle changes.
The program includes 7 sessions delivered over a 12-month period. You can choose from a group course or our telephone health coaching service. Learn more about the Life! program.
You can check your eligibility for the Life! program by taking a quick online test here.
Sources
Diabetes medicines – Diabetes Australia
Exercise & diabetes – Diabetes Australia
Fatty Liver – Symptoms, Causes and Treatment – Health Direct
https://www.healthdirect.gov.au/fatty-liver
