What is type 2 diabetes?

By June 11, 2018Blog

Type 2 Diabetes is a chronic disease in which the blood sugar or glucose level becomes abnormally high (hyperglycaemia), due to a loss in insulin secretion and/or function.

Normally, the carbohydrates we eat or drink are digested and broken down into small sugar molecules called glucose. The amount of glucose produced depends on the glycaemic index of the carbohydrate. Glucose then enters the bloodstream to supply energy to the tissues throughout the body. This rise in blood glucose post-meal, triggers the production and release of insulin, from the insulin-producing beta cells in the pancreas. Insulin allows glucose to enter the cells in the tissues that need it, reducing blood glucose levels. Once inside the cell, glucose is metabolised for energy or stored as glycogen, for later conversion to energy. In this way, blood glucose levels are maintained within a fairly narrow range to provide a constant supply of fuel to tissues.

In type 2 diabetes, insulin production from the beta cells fails (or is insufficient) and/or the effects of insulin on glucose-entry into the cells, are reduced (insulin resistance). The resulting hyperglycaemia may lead to cataclysmic effects on the body such as damage to blood vessels in the heart, brain and lower limbs, impaired eye sight, and reduced kidney function. It is therefore imperative to promptly screen for type 2 diabetes, and manage symptoms, upon any signs of the disease particularly if you are in a high-risk group (see below).

Risk factors

The risk of developing type 2 diabetes is increased with; a family history of the disease, a history of gestational diabetes, ageing (risk increases with increasing age), certain ethnic backgrounds (risk is greater if you are African-Carribean, black african, or south asian), environmental factors such as smoking, unhealthy lifestyle and being overweight (particularly around the belly). Obesity is thought to account for a third of the incidence of type 2 diabetes, and if you also have high blood pressure, high cholesterol, poor nutrition and are physically inactive, you are at an even greater risk of developing this disease. 

Symptoms of type 2 diabetes

The symptoms of diabetes can often go unnoticed, and as many as 50% of beta cells can already be malfunctioning on diagnosis. Experiencing the following main symptoms should prompt a visit to your healthcare provider:

  • Excessive thirst-as the body tries to get rid of excess glucose through the urine it also gets rid of large quantities of water.
  • Frequent urination- due to excess glucose being flushed out via the kidneys, and the extra fluids being consumed.
  • Fatigue- due to deficiency in energy sources reaching tissues
  • Blurred vision-as excess blood glucose leads to dryness of the eyes
  • Losing weight- fat stores are being used up for energy instead of glucose
  • Genital itching or thrush- hyperglycaemia allows organisms to flourish, increasing the likelihood of infections in skin and urine
  • Hunger- energy requirements are not being met from food
  • Numbness or tingling in hands and/or feet, erectile dysfunction-due to hyperglycaemia causing nerve damage
  • Slow wound healing- hyperglycaemia affects the wound healing process
  • Irritability and mood changes- due to rapid changes in blood glucose affecting the brain

Diagnosis of type 2 diabetes

One or more of the following blood tests are used to diagnose type 2 diabetes:

The A1c or glycated haemoglobin blood test measures the percentage of glucose attached to the haemoglobin (oxygen-carrying protein) in the red blood cell and indicates the average blood glucose level over the previous 10 weeks. Normal values for HbA1c are below 5.7%, prediabetes patients are typically in the range 5.7- 6.5%, and diabetes is defined as an HbA1c of 6.5% or above.

The fasting plasma glucosetest (FPG), measures the blood glucose levels after an overnight fast. FPG measurements of 5.6-6.9mmo/l reflect prediabetes, an FPG value of 7 mmo/L or more is diagnostic of type 2 diabetes.

The Oral glucose tolerance test measures blood glucose levels before and after a standard 75g oral glucose drink. Normal non-diabetics at 2 hours post oral glucose challenge have blood glucose levels less than 7.8mmo/L. Prediabetics at 2-hours post drink blood glucose levels are between 7.9-11mmol/l, while diabetics typically have 2-hour peaks of over 11 mmol/L blood glucose levels.


Type 2 Diabetes tends to be slowly progressive and in the early stages, when beta cell function is maintained, it is often treated and sometimes reversed, with lifestyle changes alone, such as nutrition and exercise. As the disease progresses, oral medications such as metformin, may be needed and once type 2 diabetes has persisted for a few years, injectable therapies including insulin may become necessary.

1. Glycaemic index
The glycaemic index (GI) of a food is an indication of whether the carbohydrate content raises blood glucose levels quickly, moderately or slowly. Different carbohydrates are digested and absorbed at different rates, and the higher the G.I value of a food, the higher and more quickly blood glucose levels increase following ingestion.

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