The Very First Energy Source… Carbohydrates

The types, sources, function and metabolism of them…

What is a carbohydrate?

• One of the six Essential Nutrients

• Your body’s main source of energy

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• Form the bulk of your diet, contributing between 55 and 60 percent of your daily calories

Please know this summary chart…(I’ll explain the arrows afterward)

The Chemistry of ‘Carbs’

• Carbs are made from 3 common chemical elements: carbon, hydrogen and oxygen

• These elements are combined in many different ways which determines the type of sugar it will be…

Types: Monosaccharides

• These are carbs composed of single sugar units

• They are the smallest of the carb molecules

• They are: (1)GLUCOSE (2) FRUCTOSE AND (3)GALACTOSE

Types: Disaccharides

• A disaccharide is composed of two monosaccharides. It is formed when two sugars are joined together and a molecule of water is removed.

• For example, milk sugar (lactose) is made from glucose and galactose whereas cane sugar (sucrose) is made from glucose and fructose. (Maltose) is made from 2 glucose molecules bonded together.

Types: Polysaccharides

• They are made up of many monosaccharides joined together by glycosidic linkages

• Very large, often branched, molecules

• They tend to be insoluble in water, and have no sweet taste

• The 2 main types are Starches and Fibers

Starches = storage form of energy in plants. Made from many glucose molecules joined together (corn, potatoes etc)

Fibers = these make up the tough, fibrous cell walls of plants. They are found only in plant foods. We cannot digest fiber, but the bacteria found in our GI tract can

The difference between Simple and Complex Carbs… it really isn’t that

complex• Because of their ‘simple structure’

MONO SACCHARIDES AND DISACCHARIDES are considered to be part of the simple carbohydrates

• The remainder of the carbs under the POLYSACCAHRIDES are considered to be the complex carbohydrates.

Types of Fibers

• Soluble = can dissolve in water and develop a gel-like consistency

- These fibers are the ones that help lower blood cholesterol levels.

• Insoluble = do not dissolve in water- These are associated with reducing cancer

risks. - Wheat bran and whole grains are high in

this.

Functions of Carbs

• There are 4 main Functions:1. Produce Energy = 4 cal of energy/gram2. Spare Proteins = save proteins for maintaining

cellular structure 3. Break down fats = fats cannot be totally broken

down without carbs. Incomplete breakdown → Ketone body formation which is basically an acidic build up (Ketosis).

4. Provide Bulk in the Diet = helps promote normal digestion and elimination of body wastes. Fiber softens stools and also slows the rate at which the stomach empties

How Your Body Uses Carbs….

Here are the steps:

1. Your digestive system breaks down poly and di saccahrides down into mono’s

2. The carbs at this point are small enough to travel across the intestinal wall

3. They then go to the liver usually as fructose and galactose.

4. The liver transforms them into GLUCOSE which is the universal form of carbs

How Your Body Uses Carbs….continued

5. The hormone (chemicals that tell other things to happen) insulin tells the body to burn off glucose and fill up on the new glucose now in the blood.

6. The remaining glucose is turned into GLYGOGEN, the storage form glucose.

7. The more complex the carb the longer this process takes and the longer you feel full (satiety)

Other Definitions

1. Natural sugars = sugars that occur naturally in foods

2. Refined sugars = sugars that have had additives added to it like the sugar found in soft drinks

3. Supplement = a concentrated source of a nutrient that can come in the form of a pill, liquid or powder form.

Next … Sugar related conditions…