Wednesday, 27 June 2012

Carbohydrates - What Are They?

Carbohydrates - What Are They?

 Having looked at the information on happiness someone asked me “what are carbohydrates?” So I though I had better explain

Our bodies need energy and glucose is the type of sugar found circulating in the blood. It provides all of the cells of the body with energy. Every organ in the body is made up of cells and every cell needs energy.

Where does glucose come from?

Glucose is produced by carbohydrates like bread, pasta, rice, table sugar, sweets, cakes and potatoes being broken down in the process of digestion into glucose, which is then absorbed into the blood.

Understanding carbohydrates

Carbohydrates are sugars and starches – bread, potatoes, rice, pasta, cereals and sugar. They provide the energy our bodies need for all its various activities.

Different types of carbohydrate

Not all carbohydrates are the same!

Sugars and Sugary carbohydrates

¨      Sugary carbohydrates are a more concentrated source of carbohydrate. Examples are white and brown sugar, which are virtually pure carbohydrate and contain no other nutrients.  They are sometimes called “empty calories” as they only provide energy and no other nutrients

¨      Sugary foods, such as cakes, soft drinks and biscuits contain a significant amount of sugar.

¨      It is easy to eat large amounts of carbohydrates as sugars and sugary foods.

Starchy carbohydrates

¨      Starchy carbohydrate, those such as cereals and bread, have other nutrients in them alongside the carbohydrate.

¨      Because the starchy carbohydrates contain other nutrients as well they are often more satisfying

¨      Depending on the type some take longer to be digested and absorbed and therefore tend to give more even blood glucose levels.

 Glycaemic Index GI

The rate at which carbohydrates are digested and absorbed is called the glycaemic index (GI) of a food.  These measurements of how carbohydrates affect blood glucose levels are performed on human volunteers who are given glucose or other carbohydrates and the blood glucose measured.

Foods with a lower GI help to maintain blood glucose levels at a more steady level without any peaks and troughs so they assist with better  blood glucose control. Additionally, due to this blood glucose control they make you feel full for longer which helps to stave off hunger pangs so can help with weight loss. They can also make sure your brain has that constant energy supply it needs so it can make people feel less irritable and also concentrate better.

Sports people find that such lower GI foods help them to exercise for longer and often refer to them as “slow burning carbs.”

Glucose or items containing it are absorbed rapidly –indeed this is why it is used in hypo situations for people with diabetes. As it raised the blood glucose levels rapidly it is said to have a GI of 100.

The GI of different foods can be influenced by

·        The way food is prepared such as the more processed it is the higher the GI for example fruit juice has a higher GI

·        The amount of soluble fibre reduced the GI so oats and lentils have a lower GI

·        The actual chemical structure of the carbohydrates in the starch molecules so for example basmati rice (a different variety ) has a lower GI than ordinary white rice

·        If foods have been cooked than cooled the GI reduces so potatoes in a potato salad will have a lower GI than those freshly cooked

·        Tough coatings like are found in seeds will reduce the GI so grain breads have a lower GI than wholemeal bread

 Levels of GI

  •  Carbohydrates which produce a GI of over 70 are said to have a high GI—These foods obviously include glucose plus white and wholemeal breads and mashed potatoes
  • Carbohydrates which produce a GI of between 56-69 are said to have a medium GI. These foods include sultanas, canned apricots, ice cream and egg noodles
  • Carbohydrates which produce a GI of below 55 are said to have a low GI. These foods include chickpeas, lentils, green vegetables, sweet potatoes, green leafy vegetables, plums, apples and pears 

 Glycaemic Load (GL)

 This is a consideration of both the GI plus the amount of carbohydrate in a food. It is calculated by multiplying the amount of carbohydrate in a normal portion of a food by the GI and then dividing by 100.

 GL levels are

  • Low below 0-10
  • Medium 11-19
  • High 20 plus
There are various books with tables in to help with this This includes some I have written.

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