THIRUVANANTHAPURAM: Did you know that diabetes is one of the oldest diseases known to man? Of course, it was not known as ‘diabetes’ in ancient India but as ‘madhu meha’ or ‘honeyed urine’. As early as 1,500 BC, physicians noticed that ants were attracted to the urine of certain patients who had complained of frequent urination, fatigue and thirst. They observed that this urine was sweet or ‘honeyed’. Interestingly, the ancient Greeks believed that frequent urination, which was one of the symptoms of the disease, was caused by flesh that was melting down and being converted into urine. Further observations by Indian physicians, Charaka and Sushrutha around 400 to 500 BC added to our knowledge of madhu meha. They identified two types of madhu meha, and categorised the first type as being associated with youngsters and the second type as affecting obese older people.
The word ‘diabetes’ itself was coined in 200 BC by a Greek physician, Appollonius of Memphis. It means ‘to siphon’ or ‘pass through’. The name was first recorded in English in a medical text written around 1425. It was in 1675 that Thomas Willis added the word “‘mellitus’ - meaning honeyed or sweet - to ‘diabetes’, and today the disease is known as diabetes mellitus.
The first test for diabetes was the urine taste test. In ancient times, people known as ‘water tasters diagnosed diabetes by tasting the urine of people suspected of having the disease. If you ask me, it was a rather unpleasant way of earning a living! It was only in the 1800s that scientists developed chemical tests to detect the presence of sugar in the urine.
By the twentieth century, tests for blood glucose- the term used for the sugar present in your blood- were developed. In 1964, a drop of blood was placed on a paper strip and then washed off. Comparing the colour to a standardized colour chart gave the doctor a rough indication of the level of glucose in the blood. Today, there are different tests for diabetes. FBS is a test that has to be performed by drawing a blood sample from a vein, after twelve hours of fasting.
It measures the fasting blood sugar levels. After giving a blood sample to determine FBS, the patient consumes a heavy meal. Approximately between 11/2 to 2 hours after eating, a second blood sample is drawn from the vein for testing. This is known as the Post Prandial Blood Sugar test, or PPBS test. A third test is the Glucose Tolerance Teat or GTT which is performed after consuming a concentrated amount of glucose dissolved in water.
If you have been confirmed as being diabetic, your doctor will probably ask you to have a test called HbA1c done as well. Why is this test considered an important diagnostic tool for diabetes?
To understand this, let us backtrack a little. Haemoglobin is a protein found in red blood cells. It gives your blood its red colour and carries oxygen to different parts of the body. When the glucose in your blood builds up, it binds to the haemoglobin, to make a ‘glycosylated haemoglobin’ molecule. This molecule is called haemoglobin A1C or HbA1C. The more glucose there is in the blood, the more haemoglobin A1C or HbA1C will be present.
The HbA1c test identifies a three month average of glucose concentration in the blood. The reason a three-month average is taken is that after four months, red blood cells begin the process of decay. For people without diabetes, the normal range for the haemoglobin A1c level is between 4 per cent and 5.6 per cent. Haemoglobin A1c levels between 5.7 per cent and 6.4 per cent mean you have a higher chance of getting diabetes. Levels of 6.5 per cent or higher mean you have diabetes.
FBS and PPBS levels give us information about the present, while HbA1c levels give us to give a picture of blood glucose control over a long period of time. In fact, HbA1c is the only proven indicator of a person’s risk of developing complications. Both tests are important in order to get immediate, as well as the long-term information that is needed to make decisions about managing the disease. search of ‘honeyed’ urine!The author has a PhD in Biochemistry from the Indian Institute of Science, Bangalore and retired as Head of the Food Technology and Enzyme Engineering Division of the Bhabha Atomic Research centre, Mumbai.