Glucose intolerance and insulin-related conditions

Posted on 30 November 2016

We asked Dr Jacques van Staden, a GP at Mediclinic George who specialises in diabetes, about insulin-related conditions other than diabetes and how to spot them. The umbrella term for these conditions is glucose intolerance, meaning your body does not tolerate glucose well.

Many people are aware of the problems that arise from type 1, type 2 and gestational (pregnancy) diabetes, but what are insulin resistance and pre-diabetes, and how are they distinguished from diabetes?

Insulin resistance

Dr van Staden explains that insulin resistance is a pathological condition in which the body is unable to react normally to glucose and produce the right amount of insulin. Essentially, cells do not respond properly to insulin and cannot easily absorb glucose from the bloodstream to be used as energy. As a result, the body needs higher levels of insulin to help glucose enter cells. The beta (insulin-producing) cells in the pancreas try to keep up with this increased demand by producing more insulin. However, while the beta cells are still able to produce enough insulin to overcome the insulin resistance, blood glucose levels stay within the normal range.

People become insulin-resistant over a long period of time, and it is caused by an increased waist circumference or central obesity (informally called the ‘apple’ body shape). There are also other conditions that precipitate insulin resistance, such as polycystic ovarian syndrome (PCOS) in women.

If someone has insulin resistance it doesn’t mean they are diabetic, but they will struggle to lose weight and may become diabetic in the future. Insulin resistance is treated by losing weight and restricting the amount of starch and sugar in the diet. These dietary guidelines also improve the symptoms of PCOS.


‘It takes about eight years of showing blood glucose levels above normal before someone develops full-blown diabetes,’ says Dr van Staden. ‘This is why healthcare professionals in the USA try to enforce fasting blood glucose tests across the population to pick up pre-diabetes.’

Pre-diabetes, therefore, is defined as having elevated blood glucose levels that are still below diabetic levels.

Testing for hyper- and hypoglycaemia  

A fasting blood sugar test is one taken when you have not had anything to eat or drink for the previous eight hours. Testing at other times throughout the day, called un-fasted blood sugar, while more random, can help someone keep their blood sugar under control.

Here is the indication of the range of fasting blood sugar measurements and the associated conditions:

  • <4 mmol/l*: Hypoglycaemia (low blood glucose), where if it drops further you are at risk of going into a coma.
  • 4 – 5.5 mmol/l: Normal blood glucose.
  • 5.5 – 6.9 mmol/l: Pre-diabetes.
  • 7 mmol/l and above: Hyperglycaemia (high blood glucose) – and if the reading is consistently high, also diabetes.

*The international standard way of measuring blood glucose levels is in terms of a molar concentration, measured in mmol/L (millimoles per litre).

Many of these insulin-related conditions, if caused by bad lifestyle choices, are reversible. The most effective treatment is regular exercise to improve muscle tone, burn more glucose and reduce excess weight, as well as a diet low in starch and sugar.

Published in Diabetes

In the interest of our patients, in accordance with SA law and our commitment to expertise, Mediclinic cannot subscribe to the practice of online diagnosis. Please consult a medical professional for specific medical advice. If you have any major concerns, please see your doctor for an assessment. If you have any cause for concern, your GP will be able to direct you to the appropriate specialists.

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