Glucose And The Glycemic Index
Glucose or C6H12O6 as it is called in biology, is an important constituent of the human body. It is the body’s main source of energy and is mostly derived from digesting sugar and starch from carbohydrates such as rice, pasta, fruits and pasty.
The digestive system breaks down the starch and sugar in these foods, to produce glucose. Once the glucose reaches the bloodstream, insulin, excreted by the pancreas joins with the glucose.
Some of the glucose enters the body’s cells giving the body enough energy to undertake its day-to-day activities.The rest of the glucose is stored in the muscles and liver for later use. Excess sugar becomes fat, which is stored throughout the body. This explains why you are getting fat from eating too much rice.
Glucose is particularly important to the brain and red blood cells, which use no other type of fuel. The brain is particularly sensitive to shortages in glucose, which is why diabetics tend to feel very “light headed” when their sugar levels are low. Luckily the body has a number of mechanisms that keep a supply of glucose to the brain. Should the glucose levels fall too low then the person will go into a coma, so that fuel to the brain can be maintained.
Glucose in its purest form is found in a considerable number of foods. In the USA and many western countries the most common food additive comes from cornstarch. There are also other forms of glucose used in food production such as fructose which is derived from fruits and vegetables.
In 1981, Dr. David Jenkins, a professor at the University or Toronto developed the Glycemic Index (GI). This is a rating system for foods and each type of carbohydrate has an assigned numerical value. These values give the food its Glycemic Index or GI which is based on how each food affects the body’s sugar levels.
The Glycemic Index uses pure glucose as its control food and rates all other carbohydrates in relation this base-line. Thus white bread, also used as the control food, is rated as “100” and all other foods related as high, medium and low with a corresponding numerical value. The tests were on how the foods affect a person’s blood sugar, insulin and lipid levels compared to the base-line of glucose or white bread.
A “high” rating corresponds to a GI of above 70 and a “low” rating is considered to be 55 or lower. Therefore a “medium” GI food is within the range of 56 to 69.
Although all foods affect different people in different ways, the actual Glycemic Index testing was undertaken in a very scientific manner and many different test subjects from different backgrounds were used within the tests.
Foods that have a high GI are broken down quickly by the body and the glucose, vitamins and minerals from the food quickly enter a person’s bloodstream. This often gives the person a feeling of energy and euphoria – often called a “sugar high”. This explains the love of sweet foods such as candy, ice cream and chocolate, particularly when a person is unhappy.
Low GI foods are absorbed by the body in a slower fashion, avoiding any sudden highs and ensuring that energy is available to the body over a longer time period.
Foods also have an effect on insulin levels with the body. Insulin is the traffic police of the body. It tells the body’s cells whey they have had enough glucose and other nutrients. It then re-routes the extra glucose to the liver and muscles to be stored for later use. Any excess is then rerouted as fat cells to be stored in those all too familiar places on the body.
Eating too many high GI foods regularly forces insulin to be continuously released by the beta cells within the pancreas. Insulin unlocks cells throughout the body, allowing glucose to enter and become available for fuel.
If the insulin cannot keep up with the work load, this is called “insulin resistance” and is the leading cause of Diabetes 2, which can be managed by diet and exercise or pills.
Where insulin is not released or released in insufficient amounts, this can lead to Diabetes 1 and insulin will need to be injected for the rest of the person’s life.
Both kinds of diabetics have to regularly measure the amount of glucose or sugar in their bloodstreams. Following a GI diet makes it far easier to control a person’s sugar levels and lessen the possibilities of the medical problems that diabetes can trigger. Too much glucose within the blood stream triggers a number of symptoms and long term medical problems, particularly within the heart, kidneys, nerves and eyes.
Many hospitals are now absorbing and following the Glycemic Index study and teaching their overweight and/or diabetic patients how to more easily regulate their glucose levels and stop excess glucose being turned into fat within the body. There are also a considerable number of diets that follow the teachings of the Glycemic Index study, meaning that people can now be sure of which carbohydrates will cause problems and lead to too much glucose within a person’s bloodstream.