The Carbohydrates: Sugars, Starches and Fibers

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The CarbohydratesSugars, Starches and Fibers

• Chapter 4

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Carbohydrates Function

• ENERGY! ENERGY! ENERGY!
• 1. Immediate energy in the form of GLUCOSE
• 2. Reserve or stored energy in the form of
  GLYCOGEN

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Types of Carbohydrates

• Simple Carbohydrates
• (Sugars)
• Monosaccharides
• Disaccharides
• Complex Carbohydrates
• (Starches and Fibers)
• 1. Polysaccharides

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The Monosaccharides

• Definition Mono One
• Saccharide Sugar
• 1. Glucose
• 2. Fructose
• 3. Galactose
• The suffix ose refers to sugar.
• Monosaccharides are chemically bound to form the
  disaccharides. (ditwo)

GFG
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Simple Carbohydrates The Monosaccharides

• Glucose C6H12O6
• The essential energy source for all body
  functions.
• Other names Dextrose and Blood Sugar.
• A component of each disaccharide.

The ring form of a glucose molecule is called a
5-carbon ring.
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Simple Carbohydrates The Monosaccharides

• Fructose
• The sweetest of all sugars
• (1.5 X sweeter than sucrose)
• Occurs naturally in fruits and honey
• the fruit sugar

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Simple Carbohydrates The Monosaccharides

• Galactose
• Seldom occurs freely in nature
• Binds with glucose to form sugar in milk
  lactose.
• Once absorbed by the body, galactose is converted
  to glucose to provide energy.

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Simple Carbohydrates The Disaccharides

• Combination of 2 monosaccharides.
• Combined by a condensation reaction.
• Broken apart by a hydrolysis reaction.
• The Disaccharides
• 1. Maltose
• 2. Sucrose
• 3. Lactose

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Simple Carbohydrates The Disaccharides

• Maltose
• Maltose Glucose Glucose
• (via an alpha bond)
• Produced when starch breaks down.
• Used naturally in fermentation reactions of
  alcohol and beer manufacturing.

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Simple Carbohydrates The Disaccharides

• Sucrose
• Sucrose Glucose Fructose
• (via an alpha bond)
• Table sugar
• Found naturally in plants sugar cane, sugar
  beets, honey, maple syrup
• Sucrose may be purified from plant sources
  into Brown, White and Powdered Sugars.

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Simple Carbohydrates The Disaccharides

• Lactose
• Lactose Glucose Galactose
• (via a beta bond)
• The primary sugar in milk and milk products.
• Many people have problems digesting large amounts
  of lactose (lactose intolerance)

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The Complex Carbohydrates

• Polysaccharides containing 2 or more
  monosaccharides attached together
• Three types are important in nutrition
• 1. Glycogen- digestible
• 2. Starch- digestible
• 3. Fiber- indigestible

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The Complex Carbohydrates

• Glycogen
• The storage form of glucose in the body.
• Stored in the liver and muscles.
• Found in tiny amounts in meat sources.
• Not found in plants.
• Not a significant food source of carbohydrate.

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The Complex Carbohydrates

• Starch
• The major digestible polysaccharide in our diet.
• The storage form of carbohydrate in plants.
• Sources Wheat, rice, corn, rye, barley,
  potatoes, tubers, yams, etc.
• Two types of plant starch 1. Amylose
• 2. Amylopectin

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The Complex Carbohydrates

• Fiber
• Indigestible polysaccharides
• Types of fiber
• 1. Soluble- gums, pectins, mucilages, some
  hemicellulose
• 2. Insoluble- cellulose, lignin, many
  hemicelluloses

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Health Benefits of Fiber

• Fiber adds mass to the feces.
• Prevents diverticulosis.
• Reduces obesity.
• May reduce cholesterol.
• May control blood sugar.
• May prevent cancer of the large intestine.

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Lactose intolerance

• Inability to digest lactose.
• Lactose becomes food for intestinal bacteria,
  resulting in painful gas and abdominal cramping.
• Treated by consuming lactase in pill form.
  Lactase breaks down lactose.
• Is NOT due to a milk allergy.

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Low carbohydrate diets Whats really happening?

• Review We know that glucose is the bodys first
  choice of fuel.
• Lack of glucose (from carbs) causes glycogen
  stores to be used as fuel.
• Use of glycogen causes loss in water. This is the
  initial weight loss on low carbohydrate diets.

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Low carbohydrate diets Whats really happening?

• The body searches for fuel it chooses protein.
• Why? Protein can be converted to glucose.
• Protein is dismantled via (gluconeogenesis) the
  conversion of protein to glucose.

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Low carbohydrate diets What happens to your
body?

• The body needs more fuel... It turns to fat.
• Fat CANNOT be converted to glucose.
• Fat is broken down into ketone bodies used by
  tissues and the brain as an energy source.
• The result Ketosis

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Insulin Resistance

• What is it? a condition characterized by
  decreased tissue sensitivity to the action of
  insulin. This may lead to cardiovascular disease
  and/or type 2 diabetes.
• Who is at risk? Overweight individuals, those who
  have a parent or sibling with Type II diabetes,
  women who have had gestational diabetes.
• How is it detected Fasting Plasma Glucose Test
• Treatment Modified diet Diabetic diets (monitor
  fat and simple carbohydrate intake.

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What is the Glycemic Index?

• A measurement of the effect a food has on your
  blood sugar level.
• The purpose of the glycemic index is for
  diabetics who need to be concerned about their
  blood sugar levels and athletes who need to
  restore their blood sugar levels after an
  athletic performance.
• High glycemic foods will raise your blood sugar
  more rapidly ex honey, juices, potatoes, etc.

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Diets high in carbohydrate

• Excess glucose is stored as glycogen.
• When glycogen stores are full, glucose is
  converted to fat.
• Fat cells can store unlimited quantities.
• Excess of ANY nutrient results in weight gain or
  increased fat stores.

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Question Can a high-carbohydrate diet make a
healthy person fat by raising insulin and blood
sugar levels?

• Answer Too many calories, not insulin, are the
  reason people gain weight. A high-carbohydrate
  diet only makes you gain weight if you eat more
  total calories than your body burns. Insulin is
  simply the hormone that helps move blood glucose
• into cells to be used for energy.

Source The American Dietetic Association
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Dietary Recommendations

• 50-100g/ day CHO to prevent ketosis.
• Increased complex carbohydrates whole grains,
  fruits and vegetables.
• Limited simple carbohydrates sugary foods,
  potatoes, white bread, white rice.
• Fiber intake 20-35g/ day.