Download 2107lecture 5

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LAST TIME WE TALKED
ABOUT
CANADA’S FOOD GUIDE
DRIs
FOOD LABELLING
SIX DIETARY PRINCIPLES
ALL IMPORTANT TO ENSURE GOOD
NUTRITION FOR THE ATHLETE
NOW ONTO CARBOHYDRATE METABOLISM
Overview of lecture 5
Carbohydrates
-carbohydrates we digest
-structure and classification
-IDATME
-lactose intolerance, blood glucose
homeostasis, glycaemic index
-choosing carbohydrates wisely
-roles of carbohydrates
-carbohydrates digested by bacteria
-fibre-structure, classification and effects
-fibre in the diet
-IDATME
-too much fibre in diet
INTRODUCTION
CARBOHYRATES:
-COMMONLY REFERRED TO AS
SUGARS BUT THIS IS NOT
COMPLETELY ACCURATE
-CONTAIN CARBON
-CONTAIN HYDROGEN AND OXYGEN
IN THE SAME PROPORTION AS WATER
INTRODUCTION CONTINUED
- YIELD
ENERGY (GLUCOSE) AND STORE ENERGY
(GLYCOGEN)
-VERY IMPORTANT FOR NERVE AND MUSCLE
FUNCTION AMONG MANY OTHER FUNCTIONS
STRUCTURE AND CLASSIFICATION
SIMPLE
MONOSACCHARIDES
DISACCHARIDES
CARBOHYDRATE STRUCTURE
CLASSIFICATION CONTINUED
COMPLEX
OLIGOSACCHARIDES–
3-10 SUGAR UNITS
CARBOHYDRATE STRUCTURE
CLASSIFICATION CONTINUED
COMPLEX CONTINUED
POLYSACCHARIDES
MANY SUGAR UNITS STRUNG
TOGETHER
GLYCOGEN
STARCH
FIBRE
Fig. 4-9, p. 102
Fig. 4-8, p. 101
CARBOHYDRATES
DIGESTION
MOUTH-AMYLASE
STOMACH-ACID-MINIMAL
CARBOHYDRATE DIGESTION
CONTINUED
SMALL INTESTINE
-MOST OF CARBOHYDRATE
DIGESTION IN BODY OCCURS IN
THE SMALL INTESTINE:
-SMALL INTESTINE USES
PANCREATIC CARBOHYDRASES
and SMALL INTESTINAL
CARBOHYDRASES
Fig. 4-10, p. 104
CARBOHYDRATE DIGESTION CONTINUED
MINIMAL DIGESTION BY HUMANS
OF FIBRES AND SOME RESISTANT
CARBOHYDRATES
(e.g. RESISTANT STARCHES)
CARBOHYDRATE DIGESTION
CONTINUED
file:///D:/Media/Animations/chapter4/Carbohydrate_Digestion/0410update.html
LACTOSE INTOLERANCE
INTOLERANCE IS NOT AN
ALLERGY-ALLERGIES DUE TO
PROTEINS AND OTHER AGENTS
THAT PRODUCE AN ALLERGIC
RESPONSE
LACTOSE INTOLERANCE IS DUE TO :
REDUCTION IN THE:
AMOUNT AND/OR ACTIVITY
OF LACTASE-CAN BE UP TO
90-95 % LOSS OVER TIME
STRONG GENETIC COMPONENT
SYMPTOMS OF LACTOSE
INTOLERANCE
GAS, ACIDS FROM BACTERIAL
DIGESTION OF LACTOSE
RESULTING IN CRAMPS,
ABDOMINAL DISTENSION,
DIARRHEA AND BLOATING
CONSEQUENCES OF LACTOSE
INTOLERANCE
DAIRY PRODUCTS-CALCIUM
HAVE TO FIND ALTERNATE
CALCIUM SOURCES
OR USE AN ORAL LACTASE OR
USE A LACTASE ADDED TO DAIRY
PRODUCT
CARBOHYDRATES
ABSORPTION
GLUCOSE and GALACTOSE
ACTIVE TRANSPORT
FRUCTOSE-FACILITATED
DIFFUSION
CARBOHYDRATES TRANSPORT
FRUCTOSE, GLUCOSE,
GALACTOSE VIA BLOOD
CARBOHYDRATES METABOLISM
UP NEXT
METABOLISM OF CARBOHYDRATES
INSULIN –GLUCOSE INTO CELLS FOR ENERGY OR
TO GLYCOGEN(PRIMARILY LIVER AND
MUSCLE)
-GLYCOGEN-STORAGE FORM OF GLUCOSE
PRIMARILY IN MUSCLE AND
LIVER
GLUCAGON- GLYCOGEN TO GLUCOSE IN CELLGLUCOSE LEAVES CELL AND
ENTERS THE BLOOD-ENERGY
Fig. 4-12, p. 109
BLOOD GLUCOSE HOMEOSTASIS
Maintaining-too low-dizzy and weak
too high-fatigued, confused and difficulty
breathing
Regulating hormones - insulin and glucagon
Balancing in normal range - insulin and glucagon
BLOOD GLUCOSE AND DIET CONTINUEDGLYCAEMIC INDEX
A scale that ranks carbohydrate-rich
foods by how much they raise blood
glucose levels compared to a standard
food (e.g. white bread). Standard food is
given a score of 100
BLOOD GLUCOSE AND DIET CONTINUED
-however, glycemic index is controversial
- inadequate science?
- determined for relatively few foods
- when determined it is based on average of multiple
tests with a great deal of variability
FOODS
GLYCEMIC INDEX
GRAINS (INCLUDES BREADS AND
PASTAS)
BREADS -WHEAT HIGHER THAN
RYE
PASTAS - LOWER THAN BREADS
RICE AND PASTA ABOUT THE
SAME AS EACH OTHER
FOODS CONTINUED
GLYCEMIC INDEX CONTINUED
VEGETABLES AND FRUITS
ON AVERAGE
GLYCEMIC INDEX
POTATO > YAM
LEGUMES > ROOT VEGGIES
FRUITS ~ LEGUMES
FOODS CONTINUED
GLYCEMIC INDEX CONTINUED
MILK PRODUCTS ~ FRUITS ON
AVERAGE
WHY? LACTOSE=FRUCTOSE
IN GLYCEMIC
INDEX
FOODS CONTINUED
GLYCEMIC INDEX CONTINUED
MEATS - VERY LOW GLYCEMIC
INDEX
- BUT DO NOT GORGE
CARBOHYDRATE EXCRETION
URINE- WATER, LITTLE SUGAR
FAECES- WATER, LITTLE SUGAR
LUNGS- CO2
SALIVA? PARTIALLY DIGESTED
CARBS?
HOW TO CHOOSE CARBOHYDRATES WISELY
1)increase intakes of whole grains
2)use whole grain products such as oatmeal,
brown rice and whole wheat bread
3)increase consumption of legumes such as
kidney, black and pinto beans)if fresh fruits
not available, choose frozen or
canned fruits without added sugar
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HOW TO CHOOSE CARBOHYDRATES WISELY CONTINUED
4)use whole grain flour for
¼ to ½ the amount of flour in the recipe
5)use less sugar in baking
6)use less added sugars in foods
7)eat fewer high sugar foods
8)use food labels to guides one’s choices
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BLOOD GLUCOSE AND DIET CONTINUED
FAD DIETS
-NO APPLES OR ORANGES BUT BACON
AND EGGS ALRIGHT-THIS IS NOT
GOOD WHY?
-AVOID OUTRIGHT!
CARBOHYDRATES
ESSENTIAL OR NOT?
YES- WHY?
HEALTHY ROLES
1) NEURAL FUNCTION
2) GIVE STRUCTURE TO MOLECULES
3) METABOLICALLY
4) IMPACT ON NUTRIENT
ABSORPTION
CARBOHYDRATE FUNCTIONSHEALTHY
NEURAL FUNCTION
BRAIN AND NERVES REALLY
ONLY SET UP TO USE GLUCOSE
LIPIDS/PROTEINS CANNOT BE
USED
CARBOHYDRATE FUNCTIONSHEALTHY continued
GIVE STRUCTURE TO MOLECULES
CARBOHYDRATE
E.G. GLYCOGEN
DISACCHARIDES
OLIGOSACCHARIDES
NON-CARBOHYDRATE
E.G. SOME PROTEINS
CARBOHYDRATE FUNCTIONSHEALTHY continued
METABOLICALLY
ENERGY -HEAT/FUEL
-SPARING PROTEIN
-BURNING FAT
CARBOHYDRATE FUNCTIONSHEALTHY continued
METABOLICALLY CONTINUED
MAKE OTHER COMPOUNDS
- GLYCOGEN
- FAT
- PROTEIN (NON-ESSENTIAL
AMINO ACIDS)
- DNA/RNA
CARBOHYDRATE FUNCTIONSHEALTHY continued
IMPACT ON NUTRIENT HANDLING
• non-absorbable oligosaccharides
impair carbohydrase activity
• starch granules exposed to moist
heat and then cooling are less
dense and hence less available to
enzyme action
Fibre structure and classification and effects
Insoluble
Cellulose-bran,vegetables
Hemicellulose-bran, whole grains
Lignins-fruits, mature vegetables, flax
Generally-accelerate gi transit, increase
fecal weight(promotes bowel movements),
slow starch digestion,
delay glucose absorption
But can be exceptions
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Fibre structure and classification and effects
continued
Soluble
Pectins-apples, carrots
gums and mucilages- oats, legumes
Generally-delay gi transit,
delay glucose absorption,
lower blood cholesterol
But can be exceptions
52
OTHER FIBRE FUNCTIONS (classifications)
- water holding capacity
- viscosity
- cation exchange capacity
- bile binding capacity
- fermentability
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How to get higher fibre in the diet
Breads cereal
Rice Group
Breads
1 slice
Cereal
½ cup
Pasta
½ cup
High
5g
Fibre content
Medium
Low
2g
0.5 g
Whole wheat
bread
All
bran
white
bread
shredded
wheat
rice
krispies
Whole
wheat pasta
macaroni
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How to get higher fibre in the diet continued
High
4g
Fruit group
1 MEDIUM
OR ½ CUP
berries
Fibre content
Medium
Low
2g
1g
apple
melon
55
How to get higher fibre in the diet continued
Fibre content
High
Medium
Low
4g
2g
1g
Vegetable
group
peas
green
asparagus
½ CUP
beans
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DRI RECOMMENDATION FOR FIBRE INTAKE
FOLLOW DRI RECOMMENDATIONS
FOR CARBOHYDRATE INTAKE AND THIS WILL
PROVIDE SUFFICIENT FIBRE
DRI - 14 GRAMS FIBRE/1000 KCAL (ROUGHLY 25-35 GRAMS
OF FIBRE/DAY) (NO DISTINCTION BETWEEN
SOLUBLE AND INSOLUBLE BUT VARIETY IS THE
KEY TO BALANCE)
57
REMEMBER THAT:
FIBRE FROM NATURAL SOURCES
RATHER THAN COMMERCIALLY
PREPARED FIBRE
IS BETTER BECAUSE
FOODS CONTAIN VITAMINS AND MINERALS
AS WELL AS THE FIBRE
58
FIBRE IDATME
•
•
•
•
•
ingestion-fibre containing foods – grains, fruits and vegetables
not digested by small intestine enzymes-why?
bacteria-make short chain fatty acids
water, gas
short chain fatty acids, water absorbed at large intestine
and transported by blood used for energy
excretion-whole or in part, gas water, short chain fatty acids
59
TOO MUCH FIBRE IN THE DIET
•FLATULENCE
•OBSTRUCT GI TRACT IF GREATER
THAN 50 G FIBRE /DAY
•TOP RECOMMENDATION IS 40 G/D
FOR ADULTS (WHO)
60
TOO MUCH FIBRE IN THE DIET CONTINUED
•INSOLUBLE FIBRE HAS PHYTATES
THAT CAN BIND MINERALSEG CALCIUM, IRON, ZINC
AND MAGNESIUM
•PREVENT ENZYME CONTACT
61
TOO MUCH FIBRE IN THE DIET CONTINUED
• INCREASES VOLUME OF FOOD
REQUIRED TO MEET ENERGY
REQUIREMENTS
• SATIETY BEFORE ADEQUATE
NUTRITION-GENERALLY ONLY A
PROBLEM IF DIET LOW IN MICRONUTRIENTS
OR IN SMALL CHILDREN (SMALL STOMACHS)
62
TOO MUCH FIBRE IN THE DIET CONTINUED
IMPORTANT TO INCREASE WATER INTAKE
WITH INCREASES IN DIETARY FIBRE
-OTHERWISE CONSTIPATION BUT IF HAVE
ENOUGH WATER CAN GET DIARRHEA
(BACTERIAL BREAKDOWN OF FIBRE)
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Summary of lecture 5
Carbohydrates
-carbohydrates we digest
-structure and classification
-IDATME
-lactose intolerance, blood glucose
homeostasis, glycaemic index
-choosing carbohydrates wisely
-roles of carbohydrates
-carbohydrates digested by bacteria
-fibre-structure, classification and effects
-fibre in the diet
-IDATME
-too much fibre in diet
NEXT TIME WE WIILL TAKE TODAY’S LECTURE
AND APPLY IT TO CARBOHYDRATES IN ANAEROBIC,
INTERVAL AND AEROBIC SPORTS
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