Friday, 28 February 2014

The secret of Glycemic Index ..............

The secret lies in the Glycemic Index (GI). A measure of how quickly blood glucose levels (i.e., blood sugar) rise after eating a particular type of food and All foods have a GI value.
But there are factors that affect the GI of your Food. Knowing them is a must.

The faster your food gets converted into glucose, the higher the GI of the food will be. The digestive system breaks down carbohydrate-containing foods into simple sugars, mainly glucose. People with Diabetes T2 have an impaired glucose tolerance (High P.P) whereby they become resistant to the action of insulin or cannot produce insulin rapidly enough to match the release of glucose into the blood after eating carbohydrate-containing foods. This means their blood glucose levels may raise above the normal level faster.

Let’s take for example, Porridge, It is digested to simple sugars much more slowly than cornflakes, so the body has a chance to respond with production of insulin, and the rise in blood glucose levels is less. For this reason, porridge is a better choice of breakfast cereal than cornflakes for people with type 2 diabetes. It will also provide more sustained energy for other people as well.

What comes along with the carbohydrate affects its GI.
Fat, Protein, Soluble fiber, Acid, fructose (a carbohydrate found in fruit) and lactose (the carbohydrate in milk), they all affect the GI. The Fats and proteins along with Carb generally slow gastric emptying of food. This is the process by which food exits the stomach and enters the duodenum. By slowing down gastric emptying the food matter is absorbed more slowly by the body which reduces blood glucose levels. Examples of foods with high fat and protein content include peanuts (GI 33). Then, the Acid foods (like vinegar, lemon juice) also slow the rate at which the stomach empties and so slow the rate of digestion, resulting in a lower GI. Other factors present in food, such as phytates in wholegrain breads and cereals, may also delay a food’s absorption and thus lower the GI.

How does your food look?

The Size: Grains that are in their original form like whole wheat and barley (Jau) have a lower GI than other forms of these substances such as refined flours.

Outer Layer or shell/covering of food
The way food is encased affects the ability of the food to be absorbed by the body. For example, bran has a physical barrier which slows down the enzymatic activity of the internal starch layer during digestion. Bran has a low GI of 38.By contrast, corn flakes a high GI food (GI 92), do not have a pronounced physical barrier like bran and are more quickly absorbed.

What you do with your food.
The GI of a food will be significantly raised by the amount of pounding, mixing, or grinding it endures. The increase occurs because the particle size is decreased, so the body does not need to do as much work to break the food down during digestion. Processed foods require less digestive processing and give rise to higher levels of blood glucose levels once absorbed by the body. For example, traditional rolled oats have a low GI of 51 whilst process quick 1-minute oats have a higher GI of 66. Juice has a higher GI than whole fruit
The cooking process swells the starch molecules in food and softens it. This speeds up the rate of digestion giving rise to higher levels of blood glucose. Pasta cooked but firm to touch boiled for 10 -15 minutes has a GI of 44 whilst the same over cooked pasta boiled for 20 minutes has a higher GI of 64. Mashed potato has a higher GI than a whole baked potato

The Ripeness and storage time
The more ripe a fruit or vegetable is, the higher the GI.. Take for e.g. Banana, Slightly unripe banana has more starch in it as so has a lower GI.

Type of Starch your food contains
Starch is a carbohydrate which consists of two types of molecules: amylopectin and Amylose. Basically Amylose absorbs less water and is a more complex molecule, form tight clumps which slows the rate of ingestion, digestion and insulin response time, providing a lower glycemic index. Legumes like beans, lentils, peas and kidney beans, Whole-grain foods like wheat, brown rice, rye, barley, oats, corn, millet all have a high Amylose content.

1 comment:

  1. Thanks for sharing.
    Very interesting!