Insulin and Diabetes
Type 2 diabetes is a chronic disease that affects the metabolism, transport, and storage of sugars in the body. Diabetes is also a progressive disease, in that once you have diabetes and your beta cells in your pancreas are affected by the disease it will continue to progress and get worse over time. Healthy lifestyle changes such as exercise and proper nutrition help slow the progression of diabetes and will help avoid further health complications due to the disease.
As of 2005, Diabetes affected over 6% of people in Canada (approx 1.1 million people) and is predicted to affect over 2.4 million people by 2016 making diabetes the disease of the 21st century. Diabetes can be broken down into 3 different types:
Diabetes Mellitus Type I - Insulin Dependent Diabetes
A condition where the body does not produce insulin. As the beta cells stop producing insulin, blood sugar levels rise as glucose can not enter cells. Since the pancreas no longer produces insulin, the patient must inject insulin in order to mimic the bodies natural production of the hormone to lower blood sugar levels. Multiple daily injections or the use of an insulin pump is required to maintain normal blood sugars.
Diabetes Mellitus Type II - Insulin Resistant Diabetes
Diabetes where the body still has the ability to produce insulin however the insulin produced is less effective at opening the cell door to let sugar in. Diet and exercise play key roles in blood sugar control. Unlike patients with insulin dependent diabetes, people with Type 2 Diabetes can often control their blood sugars with diet, exercise and oral medications. Sometimes, patients with more severe Type 2 Diabetes will require insulin as well.
Increased insulin resistance during pregnancy which indicates underlying genetic predisposition to developing Diabetes. Women with gestational Diabetes have a 50% chance of developing Type II Diabetes. It is especially important for women with gestational diabetes to maintain healthy weight through diet and exercise to reduce the risk of developing type II Diabetes both during and after pregnancy.
Explaining Insulin and Diabetes
Insulin is a hormone that regulates the transport of sugars from the blood into the cells for use as energy. In Type 2 Diabetes there is a relative lack of insulin being produced and the insulin produced is not as effective at facilitating transport of glucose across the cell membrane. Someone with a strong family history of diabetes or who has a poor lifestyle (diet and exercise) is at increased risk for developing the disease. Conversely, insulin requirements drop with physical activity and weight loss and insulin resistance is improved.
To better explain diabetes and insulin function, I have put together the analogy below:
- A metabolically active cell = a room with a locked door that needs a key to open
- Insulin = the key to open the locked door of the cell
- Pancreas = the factory that produces these keys (insulin) as they are needed to unlock the doors
- Glucose = the source of energy to keep the the cell functioning properly
- Lock = the insulin receptors on the cell wall
Glucose is a monosaccharide that is obtained through food. It is also stored in the liver as glycogen and released in response to body needs. Glucose is an energy source for metabolically active cells in the body such as muscles, organs, and other cells. Each of these metabolically active cells have a door which needs a key to unlock in order to get the sugar into the cell, the hormone Insulin is the key to open the cell door to let the sugar in so it can be used.
In a healthy individual, all of the insulin (keys) can unlock the cell doors, however in a person with Diabetes the keys cannot open some of the doors to the cell, as a result more glucose is present in the blood stream outside of the cell which causes an increase in blood sugar levels. High blood sugar levels over time (without healthy diet and regular exercise) will cause the Pancreas (the key factory) to produce more Insulin in response to the excess sugar outside of the cells. This chronically high insulin production over time will cause the cells to become less sensitive to insulin and therefore, less of the keys that are produced will be able to unlock the cell doors. If ones Diabetes continues not to be managed over time this will cause compromised cell function, an increase in health risks, and less insulin being produced by the Pancreas which can lead to dependence on regular insulin injections.
Defined as low blood sugar levels or blood sugar readings under 4 mmol/L, hypoglycaemia is characterized by shakiness, feeling weak, low energy, tiredness, and sometimes passing out or fainting. This can be experienced by anyone with low blood sugar. Hypoglycaemia is caused by either not eating enough to keep blood sugar levels at an adequate level for normal body function or by using too much sugar during high intensity activity such as sport or exercise. In the event you begin to feel hypoglycaemic during exercise, or you test your blood sugar and it is below 4mmol/L you should intake some fast absorbing form of sugar to bring sugar levels back up to normal. Hypoglycemia is most common in patients with Type 1 Diabetes taking insulin or patients with Type 2 Diabetes on certain glucose lowering medications. Hypoglycemia is dangerous.
Defined as high blood sugar levels or blood sugar readings over 7 mmol/L, hyperglycaemia is characterized by dry mouth, excessive thirst, increased urination and sometimes blurred vision. Low energy is also a common symptom. Hyperglycaemia is caused by someone consuming too many carbohydrates or sugars which in turns causes a rise in blood glucose levels above normal levels. Persistently elevated blood sugars are associated with damage to blood vessels, nerves, heart and kidney disease. This is why diabetes is an important health condition and blood sugars must be properly managed.
How is Diabetes diagnosed?
Diabetes is diagnosed through the measurement of blood sugar. It is defined as two fasting readings above 7.0 mmol/L. A person who is not Diabetic will have a fasting blood glucose test between the ranges of 4-6.1 mmol/L. Fasting sugars between 6.1 and 7 reflect the diagnosis of 'pre diabetes'. In patients with pre-diabetes, attention to lifestyle modification can delay or prevent progression to Type 2 Diabetes. Diabetes can also be diagnosed and monitored by a special blood test called a glycated hemoglobin (HbGa1c) which provides 3 month average of blood sugar values.
Consequences of poorly controlled diabetes
Patients with poor blood sugar control are at increased risk for the following conditions, and more:
- Heart Attack and Stroke - the most common cause of death in patients with Diabetes Mellitus
- Poor circulation to legs (claudication)
- Recurrent infections - especially in the feet
- Kidney failure
- Erectile dysfunction
- Digestive problems
- Diabetic Neuropathy - chronic hyperglycaemia or chronically high blood sugar over a long period of time can eventually cause pain associated with diabetes called diabetic neuropathy. Diabetic neuropathy can be characterized by the sensation of numbing, pins and needles (paresthesia), or electric shooting of pain commonly into feet and hands. This happens in people who have poorly regulated diabetes and have constant high blood sugar levels.
- Loss of sight - similar to diabetic neuropathic pain in the feet, unregulated diabetes can lead to an eventual loss of sight through damage to blood vessels in the back of the eye
Managing Diabetes with proper diet, regular exercise, as well as lifestyle changes such as reducing stress, quitting smoking, and reducing alcohol intake is very important to prevent the progression of the disease and the increased risk for complications. For those who have a family history of Diabetes, be sure to engage in regular physical activity (at least 30 minutes per day), monitor your diet, and make appropriate lifestyle changes to help reduce your risk of developing the disease. Stay tuned for my next article on managing Diabetes with exercise for a more detailed explanation on the concepts of insulin and exercise.
Evan Ward, BScHK, CPT
CEO & Founder, DYNAMIS