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Carbohydrates
Presented by
Janice Hermann, PhD, RD/LD
OCES Adult and Older Adult Nutrition Specialist
Chemistry of Carbohydrates
 Carbohydrates Are Made Of:
Carbon (4 Bonds)
Oxygen (2 Bonds)
Hydrogen (1 Bond)
Carbohydrates
 Monosaccharides
 Disaccharides
 Simple Carbohydrates (Sugars)
 Polysaccharides
 Complex Carbohydrates (Glycogen, Starch, Fiber)
Monosaccharides
 One Sugar Molecule
 Glucose
 Fructose
 Galactose
 Same Chemical Formula
 Different Structure
 Effects Sweetness And Absorption
Disaccharides
 Two Sugar Molecules
Maltose = Glucose + Glucose
Sucrose = Glucose + Fructose
Lactose = Glucose + Galactose
Polysaccharides
 Many Sugar Molecules
 Glycogen
 Liver
 Muscle
 Starch
 Fiber
Digestion
 Mouth (salivary amylase)
 Stomach (HCl and pepsin)
 Small Intestine (pancreatic amylase)
 Intestinal Wall (disaccharidases)
 Maltase (maltose to glucose + glucose)
 Sucrase (sucrose to glucose + fructose)
 Lactase (lactose to glucose + galactose)
Lactose Intolerance
 Lactase activity declines with age and for
certain racial groups. Lactose remains
undigested and is not absorbed.
 Undigested lactose moves into the large
intestine where it absorbs water causing
bloating, abdominal discomfort and diarrhea.
 Undigested lactose becomes food for
intestinal bacteria which produce irritating
acid and gas, further contributing to
discomfort and diarrhea.
Absorption
 Lining Of The Mouth
 Small Intestine
 Some Fructose Converted To Glucose
 Fructose Absorbed Slower
 Liver
 Fructose and Galactose Converted To Glucose
Metabolism
 Storage Of Glucose As Glycogen
 Storage Form Of Glucose In Animals
 Liver Glycogen
 Brain, Nerve Cells, Developing Red Blood Cells
 Muscle Glycogen
 Glycogen Storage For Hours Not Days
 Lose Water When Breakdown Glycogen
Metabolism
 Using Glucose For Energy
 Primary Role Of Glucose
 38 ATP/glucose
 Brain, Nerve Cells
and Developing RBCs
Metabolism
 Making Glucose From Protein
 Protein Converted To Glucose
 Fat Can’t Be Converted To Glucose
 If Carbohydrate Inadequate, Converts Protein To
Glucose For Brain, Nerve Cells And Developing
RBCs
 Adequate Carbohydrate Spares Protein
Metabolism
 Using Fat for Energy
 Inadequate Carbohydrate, Fat Used For Energy For
Other Cells
 Fat Broken Into 2-C Fragments And Converted to
Acetyl CoA
 Overloads TCA Cycle
 2-C Fragments Combine Forming Ketone Bodies,
Can Lead To Ketoacidosis
Metabolism
 Converting Glucose To Fat
 More Glucose Than Needed For Energy Or
Glycogen Converted To Fat And Stored
Maintaining Blood Glucose
 Important To Maintain Blood Glucose
 Too Low (Weak/Dizzy)
 Too High (Confused/Difficulty Breathing)
 Extremes Either Way Can Be Fatal
Regulating Hormones
 Glucose Too High - Insulin
 Stimulate Body Cells To Take
Up Glucose
 Stimulates Glycogen
Synthesis
 Stimulates Triglyceride
Synthesis
 Glucose Too Low -
Glucagon
 Stimulates Liver To
Breakdown Glycogen
Falling Out Of Range
 If Blood Glucose Regulation Fails
 Diabetes
 Hypoglycemia
 Glucose May Be Modified As Part Of
Treatment, But Hormonal Regulation Or
Obesity (For Type 2 Diabetes) Is The Cause
Not Glucose
Glycemic Index
 Usefulness of glycemic index controverseal
 Controversy on health impact
 Practical utility limited
 Few foods have glycemic index determined
 Those that have based on wide variations
 Glycemic index may be unnecessary
 Current guidelines already suggest many low glycemic
index choices; whole grains, legumes, vegetables, fruits
and milk products.
 Eating frequent, small meals spreads glucose absorption
across the day and thus offers similar metabolic
advantages to eating foods with a low glycemic response
Glycemic Index
 Effect Of Food On Blood Glucose
 Glycemic Index Differs
 Amount of carbohydrate consumed
 Nature of starch
 Type of sugar
 Preparation methods
 Fat content
 Fiber content
 Most foods are eaten in combination in a meal
 Fasting and pre-meal blood glucose
Types Of Sweeteners
 Caloric Sweeteners
 Sugars
 Sugar Alcohol
 Non-Caloric Sweeteners
Sugars (provide cal
 Includes Many Caloric Sweeteners
Refined Sugars
Lactose
Corn Sweeteners
Glucose
Invert Sugars
Dextrose
Maltose
Honey
High Fructose Corn Syrup
Syrups
Concentrated Fruit Juices
Health Effects of Sugars
 Nutritional Deficiencies
 Sugar Can Only Contribute To Deficiencies By
Displacing Nutrients
 Sugars Are Not “Bad” But Nutrient Dense Foods
Must Come First
 Amount Of Sugar Depends On Calories Available
Beyond Those Needed For Nutrients
Health Effects of Sugars
 Tooth Decay
 Sugars And Starches Contribute To Decay
 Bacteria In Mouth Ferment Sugars And Produce
Acid That Dissolves Enamel
 Sugar Only One Of Many Factors
 How Long Food On Teeth
 How Often Food Eaten
 Dental Hygiene
Health Effects of Sugars
 Diabetes
 Hormonal regulation or obesity (in case of type 2
diabetes) causes diabetes - not sugar
 Carbohydrate intake, including sugar, may be
modified as part of the treatment for diabetes but
it is not a cause
 For people with diabetes, attention is first given to
total amount of carbohydrate in the diet rather
than the source
Health Effects of Sugars
 Hyperactivity/Misbehavior In Children
 Controlled Studies Failed To Show An Adverse
Relationship Between Sugar And Hyperactivity Or
Misbehavior In Children
 Carbohydrates, Including Sugars, Stimulate
Production Of Serotonin, Makes A Person Sleepy
And Sluggish
Health Effects of Sugars
 Heart Disease
 Normal Sugar Intakes Do Not Raise Triglycerides, If
Calories In Balance
 Very High Intakes Of Sucrose And Fructose Can
Increase Triglycerides
 Glucose Causes Insulin Release
 Some People Over Produce Insulin In Response To
High Glucose Or Carbohydrate
 Other dietary factors such as total fat, saturated
fat, and obesity have a much stronger association
with heart disease than sugar intake.
Health Effects of Sugars
 Obesity
 Obesity Due To Energy Imbalance
 No Direct Connection Between Sugar And Obesity,
Unless Excess Sugar Containing Foods Leads To
Energy Imbalance
 Foods High In Sugar Often High In Fat
 Increase In Calorie Intake Has Come From
Carbohydrates, And Primarily Soft Drinks
Sugar Alcohols
 Provide Calories, But Fewer Than Sugars
Because Not Completely Absorbed
 Products With Sugar Alcohols Can Be Labeled
“Sugar Free” or “Reduced Calorie”
 Incomplete Absorption Can Cause Gas,
Abdominal Discomfort and Diarrhea
 Real benefit of using sugar alcohols is that
they do not contribute to dental caries
Non-Caloric Sweeteners
 FDA Approved Non-Caloric Sweeteners
Name
Sweetness ADI
Saccharin
Sweet & Low 450x
5 mg/kg
Aspartame NutraSweet 200x
50 mg/kg
Equal
Acesulfame K Sunette
200x
15 mg/kg
Sucralose
Splenda
600x
5 mg/kg
Neotame
8,000x
18 mg/day
Non-Caloric Sweeteners
 FDA Petitioned Non-Caloric Sweeteners
 Cyclamate
 Alitame
Accepted Daily Intake (ADI)
 Amount a Person Can Safely Consume
Everyday Over A Lifetime Without Risk
 Conservative Level with a wide margin of
safety
Safety Of Non-Caloric Sweeteners
 All Compounds Toxic At Some Dose
 Question Is Whether Non-Caloric
Sweeteners Are Safe In Quantities People
Normally Consume And Potentially Abuse
Saccharine Safety
 Used Over 100 Years In US
 Not Metabolized By Body, Rapidly Excreted,
Does Not Accumulate In Body
 Originally on GRAS List
 Safety Questions Arose In 1977
 Rat Study Suggested Large Doses Increased
Risk Of Bladder Cancer
Saccharine Safety
 Large Human Studies Do Not Support An
Association Between Saccharine And Cancer
For Population As A Whole
 Subgroup May Have Increased Risk
Aspartame Safety
 Composed Of:
 Phenylalanine
 Aspartic Acid
 Methyl Group
 Extensive Studies Document Safety, Except
For People With PKU
Phenylketonuria (PKU)
 Inherited Disease Were Can’t Handle Excess
Phenylalanine (1:10-15,000)
 Accumulation Of Excess Phenylalanine and
By-Products Can Cause Irreversible Brain
Damage
 Newborns Screened For PKU
Phenylketonuria (PKU)
 Strict Diet Providing Phenylalanine For
Growth But Not Damage
 Aspartame Products Carry A Warning
 Someone With PKU Can Handle Aspartame In
A Diet Soda, But Children With PKU Need
Phenylalanine From Nutrient Rich Foods
Methyl Group
 During Metabolism:
Methyl Group ⃗ Methanol ⃗ Formaldehyde ⃗ Carbon Dioxide
 Amount Produced Fall Below Levels That
Would Cause Harm
 Many Juices Produce More Methanol Than
Aspartame In A Diet Soda
Other Accusations
 No Credible Evidence Links Aspartame To:
 Multiple Sclerosis
 Lupus
 Seizures
 Brain Tumors
 Birth Defects
Other Accusations
 Some People Claim They Have Unusual
Sensitivity To Aspartame
 Double Blind Studies Have Failed To
Reproduce Reactions
 In Conclusion, Except For People With PKU,
Aspartame is Safe.
Acesulfame K Safety
 FDA Approved Acesulfame K In 1988 After
Reviewing 90 Safety Studies
 Some Groups Believe Acesulfame K Caused
Tumors In Rats
 FDA Concluded Tumors Were Not Caused By
Sweetener
Sucralose Safety
 FDA Approved Sucralose In 1998 After
Reviewing 110 Safety Studies
Neotame Safety
 FDA approved neotame in 2002 after
reviewing 110 safety studies
 Neotame also contains phenylalanine,
aspartic acid , a methyl group and an
additional side group which blocks digestive
enzymes from separating phenylalanine and
aspartic acid
 As a result, the amino acids are not absorbed
 Neotame does not have to carry a warning
for people with PKU