Transcript Chapter 5: Carbohydrates

Chapter
4
Carbohydrates
What Are Carbohydrates?
• Organic compounds that contain
carbon, hydrogen and oxygen (CH2O)
© Vinicius
Tupinamba/ShutterStock, Inc.
© Mircea
BEZERGHEANU/ShutterSto
ck, Inc.
© Ayd/ShutterStock, Inc.
© Krunoslav
Cestar/ShutterStock, Inc.
Single Sugars: Monosaccharides and
Disaccharides
• Monosaccharides: The Single Sugars
• Glucose
• Found in fruits, vegetables, honey
• “Blood sugar”—used for energy
• Fructose
• Found in fruits, honey, corn syrup
• “Fruit sugar”
• Galactose
• Found as part of lactose in milk
Disaccharides: The Double Sugars
• Disaccharides—two linked sugar units
• Sucrose: glucose + fructose
• “Table sugar”
• Made from sugar cane and sugar beets
• Lactose: glucose + galactose
• “Milk sugar”
• Found in milk and dairy products
• Maltose: glucose + glucose
• Found in germinating cereal grains
• Product of starch breakdown
Complex Carbohydrates
• Oligosaccharides
• Human breastmilk (source of fiber for babies)
• Onions, legumes, wheat asparagus, beans
• Polysaccharides
• Starch
• Long chains of glucose units
• Found in grains, vegetables, legumes
• Glycogen
• Highly branched chains of glucose units
• Body’s storage form of carbohydrate
Complex Carbohydrates: Fiber
• Dietary + Functional = Total Fiber
• Indigestible chains of monosaccharides
• Nonstarch polysaccharides: long chains
• Cellulose, hemicellulose, pectins, gums, mucilages
• Lignins
• Found in fruits, vegetables, grains, and
legumes
#4 Carbohydrate Metabolism
• Glucose is key player
• Storing glucose as glycogen
• Liver storage
• Condensation into glycogen
• Hydrolysis for release of glucose when
needed
• Muscle storage
• Selfishly hoards glycogen
Carbohydrate Metabolism
• Glucose for energy
• Fuels most of body’s cells
• Preferred source for brain, nerve cells, and
developing red blood cells
• Cellular breakdown of glucose
• Making glucose from protein
• Amino acid conversion
• Gluconeogenesis
Carbohydrate Metabolism
• Ketone bodies from fat fragments
• Inadequate supply of carbohydrates
• Fat metabolism shifts
• Ketone body formation – starvation
• Ketosis – acid-base balance
• Carbohydrate needs for protein sparing
and prevention of ketosis
• Using glucose to make fat
#5 Carbohydrate Digestion and
Absorption
• Mouth
• Salivary amylase begins digestion of starch
• Stomach - none
• Small intestine
• Pancreatic amylase completes starch digestion
• Brush border enzymes digest disaccharides
• End products of carbohydrate digestion
• Glucose, fructose, galactose
• Absorbed into bloodstream
• Fibers are not digested but are excreted in
feces
Carbohydrate Digestion and
Absorption
#6 The Constancy of Blood Glucose
• Steady supply in blood stream
• Intestines – food
• Liver – glycogen
• Blood glucose homeostasis
• Insulin
• Glucose from blood into cells
• Glucagon & epinephrine
• Brings glucose out from storage
The Constancy of Blood Glucose
• Balancing within the normal range 70-110 mg/dl
• Balanced meals at regular intervals
• Diabetes
• Insulin is either inadequate or ineffective
• Type 1 diabetes
• Type 2 diabetes
• Hypoglycemia – usually results from
uncontrolled diabetes or other conditions
The Constancy of Blood Glucose
• Glycemic response
• Speed of glucose absorption, level of
blood glucose, and return to normal
glucose levels
• Low glycemic response
• Desired
Carbohydrates in the Body:
Homeostatsis
Regulating Blood Glucose Levels
Regulating Blood Glucose Levels
Hormones:
• Insulin – lowers
• Glucagon increases
• Epinephrine –
increases in
emergencies
© Photodisc
Ketosis Causes:
•
•
•
•
•
•
•
Starvation
Chronic alcoholism
Uncontrolled diabetes
Low fluid intake
Low carb diets
Blood becomes acidic and body dehydrates
Minimum 50-100 mg carbs needed daily to prevent
ketosis
• Death occurs within 3 weeks if body remains in
this state
Symptoms of Ketosis:
•
•
•
•
Lethargic and fatigue
Nausea and vomiting
Constipation
Acetone breath from high blood acidity
#7 Hyperglycemia
• High levels of glucose in the blood
• Obtain Proper diagnosis and causes of
high blood glucose
• Eat a proper consistent carbohydrate
diet and possible diabetes medications
Lactose Intolerance
• Symptoms of intolerance
• Gas, bloating, diarrhea
• Prevalence
•
•
•
•
•
Genetically determined
98% Thais
95% African American
93% Chinese
12% Caucasian
Lactose Intolerance
• Dietary changes
• Manage dairy consumption rather than restriction
• GI bacteria
• Fermented milk products, (Lactaid products)
• Individualized diets
#8 What is the glycemic index?
• Number classification of foods based on their
potential to raise blood glucose levels
• Not a reliable method as a snicker bar is classified
as low glycemic as 55 but that is NOT a healthy
choice for a diabetic or someone wanting to loose
weight
• Snickers bar
• 250 cals, 33 carbs, 12g fat, 4.5g sat fat, 1
gm fiber
#9 Inadequate Regulation of Blood
Glucose Levels: Diabetes Mellitus
• Diabetes mellitus
• Body either does not produce enough insulin
or does not use insulin properly
• Both genetics and environmental factors
seem to be involved
• Type 1 – no insulin is produced – insulin
injections are required with diet
• Type 2 – some insulin may be produced –
may be controlled by diet and/or medications
• See Diet and Health chapter for more
information on DM
#10 Functions of Carbohydrates in
the Body
• Normal Use of Glucose
•
•
•
•
•
Using Glucose for Energy
Storing Glucose as Glycogen
Sparing Body Protein
Preventing Ketosis
Brain cells and red blood cells require a
constant supply of glucose
#11 Carbohydrates and Health
Effects
•
•
•
•
•
•
Sugar and Dental Caries
Fiber and Obesity
Fiber and Type 2 Diabetes
Fiber and Cardiovascular Disease
Fiber and Gastrointestinal Disorders
Negative Health Effects of Excess Fiber
#12 Recommended Intakes of Starch
& Fibers
• DRI for carbohydrates
• 45 to 65% of energy requirement
• RDA for carbohydrates
• minimum130 grams per day
• DV: 300 gms per day
• Fiber
• DV: 11.5 grams per 1000-kcalories
• DRI: 14 grams per 1000-kcalories
• No UL
Carbohydrates in the Diet
• Moderating sugar intake
• Use less added sugar (white
sugar, brown sugar, honey
and syrups)
• Limit soft drinks, sugary
cereals, and candy
• Choose fresh fruits or those
canned in water or juice
© CSquared Studios/Photodisc
#13 Alternative Sweeteners
• Artificial sweeteners
• Non-nutritive sweeteners (saccharin,
aspartame, sucrolose)
• Large doses and adverse effects
• Stevia – an herbal product
• Generally recognized as safe (GRAS)
• Sugar alcohols
• Provide kcalories
• Not digested, causes diarrhea
TYPES OF FIBER, BENEFITS
AND
HOW TO INCREASE
Watch Video:
High Fiber Video
An Apple a Day…
• The old adage, “An
apple a day keeps the
doctor away” has
persisted over time due
to actual health benefits
from apples.
• Apples have a high
pectin content, a soluble
fiber known to be an
effective GI regulator.
© Photodisc
#14 Characteristics, Sources, &
Health Effects of Fibers
Effects of Excess Fiber
• With all of its health advantages, high fiber
intake can cause problems, especially in
those who drastically increase their fiber
intake in a short period of time.
• A sudden increase in fiber can cause
increased intestinal gas and bloating.
• If you increase your fiber intake, you should
also increase your water intake to prevent
constipation.
#15 Increasing Fiber Intake
• To increase your fiber intake, eat more
breads, cereals, pasta, rice, fruits,
vegetables, and legumes.
• Eat fruits and vegetables with the peel, if
possible, as this is high in fiber.
• Add fruit to muffins and pancakes.
• Add legumes, such as lentils and pinto, navy,
kidney, and black beans to casseroles.
Fiber in Selected Foods
Fibers in Selected Foods
• Remember daily recommendation for
fiber intake is 14g per 1000 calories.