Carbohydrates

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Carbohydrates
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Carbohydrates

• Most easily metabolized nutrient for the body,
  converted into glucose
• glucose provides energy for the brain and ½ of
  energy for muscles and tissues
• glycogen is stored glucose
• glucose is immediate energy
• glycogen is reserve energy

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Carbohydrates

• Compounds composed of carbon, oxygen and hydrogen
  that are arranged to make different variations of
  sugar molecules
• all plant food
• milk
• carbohydrates are not equal
• simple carbohydrates
• complex carbohydrates

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Simple Carbohydrates

• sugars
• monosaccharides single sugars
• disaccharides 2 monosaccharides

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Complex Carbohydrates

• starches and fibers
• polysaccharides
• chains of monosaccharides

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Simple Carbs

• Monosaccharides
• Mono one
• Saccharides sugar
• glucose, fructose, galactose

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Glucose

• mild sweet flavor
• known as blood sugar
• essential energy source
• found in every disaccharide and polysaccharide
• in starchy foods

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Fructose

• sweetest sugar
• found in fruits and honey
• added to soft drinks, cereals, deserts

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Galactose

• hardly tastes sweet
• rarely found naturally as a single sugar
• one of the sugars in milk

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Disaccharides

• pairs of the monosaccharides (di two)
• maltose, sucrose, lactose

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Maltose

• 2 glucose units
• known as malt sugar
• not abundant in foods

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Sucrose

• fructose and glucose
• tastes sweet
• fruit, vegetables, grains
• table sugar is refined sugarcane and sugar beets
• brown, white, powdered

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Lactose

• glucose and galactose
• main carbohydrate in milk, depending on milk's
  fat content lactose contributes 30-50 of milk's
  energy
• known as milk sugar

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Complex Carbohydrates

• polysaccharides
• glycogen and starch
• built entirely of glucose
• fiber
• variety of monosaccharides and other carbohydrate
  derivatives

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Glycogen

• limited in meat and not found in plants
• not an important dietary source of carbohydrate
• BUT
• all glucose is stored as glycogen

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Starches

• stored in plant cells (grains, vegetables,
  potatoes and legumes)

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Fiber

• structural parts of plants
• found in all plant derived food
• bonds of fibers cannot be broken down during the
  digestive process
• minimal or no energy available

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Fiber Characteristics

• soluble fibers (dissolves in water)
• easily digested by bacteria in colon
• associated with protection against heart disease
  and diabetes
• lower cholesterol and glucose levels
• found in legumes and fruits

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Fiber

• insoluble (does not dissolve in water)
• promote bowel movements
• alleviate constipation
• found in grains and vegetables
• associated with reduced cancer rates

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Meeting Fibre Needs

• Choose whole grain more than refined products
  such as white bread
• Males aged 14 to 50 need 38g of fibre daily
• Females aged 14 to 18 need 36g of fibre daily
  (decreased to 25g at age 19)

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Carbohydrate Digestion

• break down into glucose
• body is able to absorb and use
• large starch molecules
• extensive breakdown
• disaccharides
• broken once
• monosaccharides
• dont need to be broken down

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Carbohydrate Digestion

• begins in mouth
• chewing releases saliva
• enzyme amylase hydrolyzes starch to
  polysaccharides and maltose
• stomach
• no enzymes available to break down starch
• acid does some breakdown
• fibers in starch provide feeling of fullness

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• small intestine
• majority of carbohydrate digestion takes place
  here
• pancreatic amylase reduces carbs to glucose
  chains or disaccharides
• specific enzymes finish the job
• maltase
• maltose into 2 glucose
• sucrase
• sucrose into glucose and fructose
• lactase
• lactose into glucose and galactose

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• large intestine
• 1-4 hours for sugars and starches to be digested
• only fibers remain
• attract water, which softens stool

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Carbohydrate Absorption

• glucose can be absorbed in the mouth
• majority absorbed in small intestine

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Lactose Intolerance

• more lactose is consumed than can be digested
• lactose molecules attract water
• cause floating, abdominal discomfort, diarrhea
• intestinal bacteria feed on undigested lactose
• produce acid and gas

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Lactose Intolerance

• management requires dietary change
• 6 grams (1/2 cup) usually tolerable
• take in gradually
• enzyme drops or tablets
• lactose free diet is extremely difficult to
  accomplish

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Imbalance

• diabetes
• after food intake, blood glucose rises and is not
  regulated because insulin is inadequate
• hypoglycemia
• blood glucose drops dramatically
• too much insulin, activity, inadequate food
  intake, illness
• diet adjustment includes fiber-rich carbs and
  protein

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Sugar

• ½ comes from natural sources, ½ from refined and
  added
• sucrose, corn syrup, honey
• excess can lead to nutrient deficiencies and
  tooth decay
• empty calories
• sugar and starch break down in the mouth

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Sugar

• recommended intake
• added sugar no more than 10 of energy intake