The glycemic index is a tool used to measure the rate at which the carbohydrate sugar enters the bloodstream. Carbohydrates, also called saccharides, provide energy to the body like sugars. Carbohydrates are present in foods that are sweet (candy and sweet) and also in all fruits, vegetables, cereals, pulses and dairy products.There
are different types of saccharides: e.g. monosaccharides, or simple sugars, such as glucose. Disaccharides, or dual sugars, include lactose, sugar naturally present in milk and its derivatives. Another disaccharide is sucrose. Polysaccharides include starch, which is located in maize, rice, pasta, bread, breakfast cereals and other grains. Most carbohydrates are absorbed more slowly than glucose.
The circulation of glucose
After we have taken carbohydrates, sugar contained in foods is decomposed into its smallest component: glucose.
This is a simple sugar that can be absorbed through the intestinal walls and quickly enter the blood stream. Once in the bloodstream, glucose circulates for the body and goes where it needs to supply energy.
To leave the bloodstream and enter the cells of the body, insulin is needed, which opens the "door" of the cell. A slowly rising blood glucose gives the body the opportunity to freeze glucose from the blood stream efficiently and maintain normal values even after meals. A rapidly rising blood glucose can put the pancreas under stress, which is the organ that produces and releases insulin.
Low GI Benefits
Foods with a high IG enter the blood stream quickly, while those with low IG are slower to be digested in the digestive system and slower to enter the bloodstream.
We can think of foods with a low glycemic index as "slow carbohydrates" that provide several benefits. These include weight loss and its maintenance, increased insulin sensitivity, improved diabetes control, reduced risk of heart disease, improved cholesterol values, polycystic ovarian syndrome control, decreased hunger and longer sensation satiety and greater physical strength.
Some believe that glycemic load is a more useful measure than the glycemic index alone.
load is calculated by multiplying the IG of a food by its amount of carbohydrates in grams, then dividing that number by 100.
For example, the glycemic index of a mature banana is 51 and the amount of carbohydrate it contains is 25 g.
51 x 25: 100 = 12.75
This number can be rounded to 13. Thus, a banana has a glycemic load of 13.
An orange has a glycemic index of about 43 and contains 11g of carbohydrates.
43 x 11: 100 = 4.73 (rounded to 5)
It is obvious that an orange will have a smaller impact on the blood glucose. This does not mean that bananas are bad. There are many ways to measure how healthy a food is - such as vitamins, minerals and other phytonutrients that it may contain - but glycemic load is another piece of the puzzle.
Much of the vegetables have a low IG, so you can eat them without limit and enjoy the benefits of antioxidants, nutraceuticals and other vegetable compounds without the body being over-stressed to counteract a rise in blood glucose. The exception are potatoes, which have a high glycemic index.
These recommendations for a low glycemic diet are compatible with those of the American Institute for Cancer Research to prevent cancer.
D. Can consuming low glycemic food affect the onset, spread and side effects of cancer?
R. In a meta-analysis, 37 different studies were analysed. Diets with a glycemic index and a high glycemic load increased the risk of breast cancer, type 2 diabetes, heart disease, and gallbladder disease.
Glycemic index of the most common carbohydrates
These foods are classified according to their IG. The corresponding glycemic load (CG) is also calculated. It is not a complete list. If you are interested in knowing the glycemic index of all the foods you consume, consult the online database at www.glycemicindex.com.
High IG = 70 or more
Medium IG = 56-69
Low IG = 55 or less
|Carbohydrate source(s)||Glycemic index||Glycemic load|
|Wholemeal rye bread||46-55||5-7|
|All Bran cereal||38-51||8-12|
|Bread with 50% oats bran||44||8|
|Parboiled rice (converted)||38||14|
|Sucrose||60 - 65||6-7|
|Source: www.glycemicindex.com. In each category, the highest and lowest values have been deleted. Foods produced in the United States, Canada and the United Kingdom were included; others were excluded.