Herbal Health

Table sugar or refined sugar (sucrose) has a G.I. factor of only 60-65. This is because it is a disaccharide (double sugar) composed of one glucose molecule coupled to one fructose molecule. Fructose is absorbed and taken directly to the liver where much of it is slowly converted to glucose. So, the blood sugar response to pure fructose is very small (G.I. factor of 20). Thus when we consume sucrose, in effect we have consumed only half as much glucose. This explains why the blood sugar response to 50 grams of sucrose is approximately half that of 50 grams of pure maltose (where the molecules are all glucose).

Many foods containing large amounts of refined sugar have G.I. factors close to 60. This is the average of glucose (G.I. = 100) and fructose ( G.I. = 20). This is lower than that of ordinary soft bread with a G.I. factor averaging around 70. Kellogg’s Cocopops™ which contains 39 per cent sugar has a G.I. factor of 77, lower than that of Rice Bubbles™ (83) which contains little sugar.

So, contrary to popular opinion, most foods containing simple sugars do not raise blood sugar values any more than that of most complex starchy foods like bread. The same is true of honey (G.I. factor of 58). Some types of honey have a much higher G.I. factor (87) than refined sugar (65), possibly because they are a mixture of honey and glucose syrup.

Sugars that naturally occur in food include lactose, sucrose, glucose and fructose in variable proportions, depending on the food. The overall blood sugar response to a food is very hard to predict on theoretical grounds because gastric emptying is slowed by increasing concentration of the sugars, whatever their structure.

Some fruits for example have a low G.L factor (cherries have a G.I. factor of only 22) while others are relatively high (watermelon has a factor of 72). It seems the higher the acidity and osmotic strength (number of molecules per ml) of the fruit, the lower the G.I. factor. Thus it is not possible to lump all fruits together and say that they will have a low G.I. factor because they are high in fibre. They are not all equal. See the tables in Part HI to compare fruits.

Many foods containing sugars are a mixture of refined and naturally occurring sugars. The overall effect on the blood sugar response is too hard to predict. This is why we need to test the G.I. value of sugary foods in real people before we make generalisations about their G.I. factor.

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In 1921 Charles Best and Frederick Banting, both Canadians, came together in Toronto to work on an idea of Banting’s to try to isolate a substance from the pancreas of dogs that might be successful in treating diabetes. They worked in experimental laboratories in the University of Toronto, Department of Physiology.

Up to this time the problem was that the digestive juices also made by the pancreas tended to destroy the chemical substance that they were trying to extract. Their first stage was therefore to inactivate the part of the pancreas making digestive juices. They did this by tying the tube or duct leading from the pancreas to the intestines and this led to the degeneration of all the pancreas except the important islet cell tissues.

This pancreatic tissue they then ground up and extracted with fluids. This extract they then injected into dogs with diabetes.

The extract led to control of the diabetes in these dogs and the substance they had extracted they called ‘Isleton’ because it had been made from the islet cells. Later they changed the name to ‘Insulin’.

This happened in 1921, and during that eventful year they conducted many experiments to find out the best way to produce a potent and effective preparation of insulin which would be suitable for using on human patients with diabetes.

The first patient to receive insulin treatment was a boy called Leonard Thompson, who had developed diabetes two years earlier when he was 11 years old. He was now at the last stages of diabetes and was dying. He was given insulin that had been extracted from beef pancreas by Banting and Best’s method. As a result of this insulin, his condition dramatically improved and his diabetes was controlled. His life was saved, and a tremendous medical achievement was made. This demonstration of the success of the insulin in treating persons with diabetes led to the urgent work of finding a way to make insulin in large quantities commercially for the many diabetics requiring treatment. This was done, under Charles Best’s direction, in the Connaught Laboratories with the assistance and support of The Lilly Company of Indianapolis USA. So successful was this work that commercial quantities of insulin were being produced in 1922, the year after its first discovery.

One drawback of the early insulin was that it had to be given several times a day as it only acted for a few hours. Further research on insulin has been directed to perfect its production and to produce forms of insulin which have a prolonged action so that they need to be given only once or twice a day. Dr Hagedorn of Copenhagen in Denmark found that when insulin was combined with a protein chemical called protamine its action was prolonged. Further lengthening of insulin action has been achieved by combining this protein and insulin with the element zinc. Since then other research work has led to several newer and different forms of insulin with different ranges of activity. These different insulins make it possible for the doctor to choose a suitable insulin or combination of insulins to meet the varying needs of different patients.

Currently, research is going even further into the precise ways that insulin works to control the body’s use of glucose and fats and also to discover the basic cause of diabetes. When we know these things it may be possible to achieve one of our ultimate goals, which is to prevent people developing diabetes. We hope it will also lead to even better and easier ways of treating it.

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