Type 2 Diabetes

What is Diabetes?

Diabetes is a group of metabolic disorders that all manifest in one common symptom, namely high blood glucose levels. The underlying defect that leads to its development always relates to the hormone insulin, either as a result of a deficiency, or due to a fault in the way insulin conducts its biological function. In many cases, a combination of both these two defects is present in the same individual.

What are the different types of diabetes?

There are 3 different subtypes:
Type 1 diabetes
Type 1 diabetes is caused by the loss or destruction of the insulin-producing units in the pancreas, called ‘beta cells’. This leads to an acute or chronic shortage of insulin, causing blood insulin levels to drop. The majority of cases occur as a result of an auto-immune attack, where the body accidently destroys its own beta cells. Most people affected by type 1 diabetes are otherwise healthy and of normal weight. The onset of the condition is mostly sudden and symptoms develop rapidly. Type 1 diabetes accounts for about 5-10% of all diabetes cases.

Type 2 diabetes
Type 2 diabetes is caused by a sequence of events during which the body becomes less responsive to its own insulin. The underlying mechanism that leads to the development of type 2 diabetes is therefore referred to as ‘insulin resistance’. Unlike type 1, insulin levels actually rise as a result of insulin resistance, although a decrease in levels may also ensue at a later stage as the condition progresses and the beta cells fail to meet the increasing demand. The onset of the condition is usually slow and symptoms are often so subtle that they may go unnoticed for many months or even years. Type 2 diabetes accounts for about for 90-95% of all diabetes cases.

Gestational diabetes
Due to various physiological and metabolic changes that a pregnant woman naturally undergoes during the normal course of pregnancy, elevated blood glucose levels may occur. This is called ‘gestational diabetes’ and occurs in about 2-10% of all pregnancies. Resembling type 2 diabetes, gestational diabetes usually disappears after childbirth. However, having had gestational diabetes at some stage increases your risk of developing type 2 diabetes later in life.

What does the term’ pre-diabetes’ mean?

Pre-diabetes is the term used when fasting blood glucose levels are higher than normal, but not sufficiently elevated to qualify for the more formal diagnosis of diabetes. Pre-diabetes is also referred to as ‘impaired glucose tolerance’.

How common is diabetes?

The World Health Organisation (WHO) currently estimates that 10% of South Africans have elevated blood glucose levels. Globally, 285 million people are diagnosed as diabetic and this number is expected to increase to 439 million by 2030. Africa is set to experience a 100% increase in the number of diabetes cases in the next 15 years.

This increase is attributed to the growing obesity epidemic, urbanisation and increased life expectancy. However, many individuals with diabetes are unaware that they have the condition. A recent report released by the Centers for Disease Control and Prevention (CDC) indicated that 25% of Americans who have diabetes are currently undiagnosed. This figure is most likely to be much higher in South Arica.

What are the symptoms of type 2 diabetes?

Common symptoms include thirst, increased urination, fatigue, irritability, nausea, increased appetite, loss of weight, blurred vision and headaches. However, unlike type 1, type 2 diabetes may present in a slow and subtle manner with symptoms hardly even being obvious.

What are the complications associated with type 2 diabetes?

In uncontrolled diabetes, various pathological processes can develop that may lead to a number of serious life-threatening complications. This includes a significant risk of developing cardiovascular disease (CVD), which may result in heart attacks and stroke. If left unchecked, chronic elevated blood sugar levels cause tissue damage to a variety of organs, including the kidneys, eyes, peripheral nerves and all blood vessels. In most countries, uncontrolled diabetes is ranked amongst the leading causes of blindness, renal failure and lower-limb amputation.
The mechanisms that lead to these complications are complex and involve the direct toxic effects of high glucose levels on bodily tissue, together with the structural defects that occur in blood vessels such as arteries and capillaries.

Common complications of type 2 diabetes are:

  • Cardiovascular disease (angina, hypertension, heart attacks and heart failure).
  • Eye disorders (damage to the retina, cataracts, glaucoma and blindness).
  • Nerve disorders (neuropathy, numbness, tingling, burning, pain and poor bladder control).
  • Kidney failure.
  • Sexual dysfunction.
  • Dementia and cognitive dysfunction.
  • Poor wound healing and increased risk of infection.

What are the causes and risk factors associated with type 2 diabetes?

Non-modifiable risk factors for type 2 diabetes which cannot be changed are age, family history and race (genetic predisposition). Modifiable risk factors are associated with lifestyle and can all be changed to reduce the risk. These are excess body fat, smoking, a sedentary lifestyle and a poor diet.

How are diabetes and the metabolic syndrome linked?

Both pre-diabetes and type 2 diabetes are directly linked to metabolic syndrome.

How are diabetes and excess body fat linked?

Excess body fat plays a major role in the development of type 2 diabetics. This is because increased fatty deposits, especially those that accumulate around the abdominal area, cause various biochemical abnormalities that lead to insulin resistance. Read more about insulin resistance

What lifestyle measures can I take to prevent or manage diabetes?

Research has shown that by combining lifestyle changes with diabetic medication, the incidence of diabetic complications are reduced by 58%. This illustrates the significance and importance of lifestyle changes, not only in the prevention, but also in the management of diabetes. These include establishing healthy eating patterns, exercising regularly and losing weight where necessary.

Weight loss is mandatary in all overweight individuals with pre-diabetes or type 2 diabetes. The therapeutic advantages of weight loss not only help blood glucose levels, but also lower cholesterol and blood pressure levels too.

Which diet should I follow to help manage diabetes?

In the past, diabetics were advised to follow a “diabetic diet” rich in “complex carbohydrates” such as crackers and breads. The basic idea behind this concept was that complex carbohydrates in theory will take longer to digest in the intestines and therefore release glucose at a slower rate. “Simple carbohydrates”, in contrast, like sugars and fruit, would be absorbed too rapidly and were therefore limited or virtually forbidden.

However, according to the Glycaemic Index (GI), a more modern classification representing the total rise in a person’s blood glucose level following carbohydrate consumption, this advice was based more on assumption than fact. Most crackers and bread, for example, raise blood glucose levels much faster than pure white sugar. Fruit, especially grapes, were often excluded in the past, but vegetables such as potatoes were considered beneficial. Again, the GI has proved that this concept has little scientific foundation, since a baked potato, for example, has a much higher GI value than grapes, and therefore raises your blood glucose levels much faster.

The concept of the “diabetic diet” has therefore become obsolete, and the principles of diabetic dietary management are basically the same health-orientated guidelines that everyone should follow to control their body weight and reduce their risk for cardiovascular disease (CVD). Since diabetics have a higher risk of developing elevated blood cholesterol, hardening of the arteries and cardiovascular disease, it is therefore also important that diabetics adhere to a diet low in saturated fat, in spite of new controversial opinions regarding the intake of saturated fat.


  1. Prof. P Rheeder. Type 2 diabetes: an emerging epidemic. SA Fam Pract 2006;48(10): 20
  2. Centers for Disease Control and Prevention. National Diabetes Statistics Report, 2014.
  3. American Diabetes Association. Diagnosis and Classification of Diabetes Mellitus. Diabetic Care Vol 37, Supplement 1, January 2014
  4. Alan J Garber et al. American Association of Clinical Endocrinologists’ Comprehensive Diabetes Management Algorithm 2013 Consensus Statement. Endocrine Practice Vol. 19 (Suppl 2) May/June 2013


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