Posted by kathryn in Uncategorized

A couple of days ago I blogged about why you should be eating carbohydrates. The simple truth is they’re impossible to avoid. But what happens to that carbohydrate once it enters your mouth?

Carbohydrates are the most widely consumed substance in the world, second only to water. Most cultures have carbohydrates as their staple foods. Whether it’s rice, corn in the form of polenta or maize, pasta, breads, potatoes, couscous – carbohydrates are the foundation foods of the majority of the world’s population.

What are carbohydrates made of?

The basic building block of carbohydrate is a sugar molecule. This is a simple combination of carbon, hydrogen and oxygen atoms. Sugar molecules are bound together in lots of different combinations, to make up all the different carbohydrates we eat. Some carbohydrates contain hundreds of these smaller sugar molecules.

Glucose is the primary energy source for your body. It’s a single sugar molecule, small enough to cross into the blood stream and be utilised by the body. However, we rarely eat glucose in its pure form. Instead, before we can make use of the carbohydrate in our food, it has to be broken down into glucose units. This is part of your body’s digestive process.

How do you digest carbohydrates?

The digestion of carbohydrates starts in your mouth. Enzymes in saliva kick things off by breaking apart carbohydrate molecules. In contrast nothing much happens to carbohydrates in the stomach. Instead, the next stage of digestion occurs in the small intestines. Here, enzymes produced by the pancreas break down the remaining carbohydrate into individual glucose molecules. These are then absorbed through the digestive tract wall, into your bloodstream.

The speed at which this occurs depends on the nature of the carbohydrate itself. Among the factors that affect carbohydrate absorption are:

• the structure of the carbohydrate molecule
• whether it’s bound up with fibre
• how it exists in the foodstuff

This means some carbohydrates break down really quickly and easily. Others take a longer time, are much more difficult to break down and release their glucose molecules more slowly.

What does insulin do?

Insulin is a hormone, produced by your pancreas. Once the carbohydrates from your food are digested and absorbed into your blood stream, your pancreas excretes insulin.

Insulin is what moves the glucose from your blood into individual cells, so it can be used to fuel your body.

The amount of insulin released by your pancreas depends on the amount of glucose in the blood stream. A large amount of glucose means a lot of insulin is released by the pancreas to deal with it. In contrast, if there are only small amounts of glucose, only small amounts of insulin are needed.

Over the next week I’ll be continuing this series on carbohydrates. The next post will touch on the problems of having too much insulin and how this can be controlled.

29 September, 2007