chapter 4: sugars, starches and...
TRANSCRIPT
Chapter 4: Sugars, Starches and Fibers
Copyright © 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
Student learning outcomes: At the end of this chapter, you should be able to:
Compare and contrast whole grains and refined sugars
Compare and contrast types of carbohydrates
Describe the role of carbohydrates in health and disease
Plan a diet to meet carbohydrate recommendations
© 2012 John Wiley & Sons, Inc. All rights reserved.
THINK about this – then share within a PAIR – then SHARE with the class
What do you know about sugars, starches, and fibers?
What are whole grains and refined sugars?
How whole grains and refined sugars important for your health?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Whole grains vs. refined grains
Whole grains: contain the whole kernel, including the brain, germ, and endosperm
Refined grains: foods processed to remove course parts such as the bran and germ which removes the fiber and some vitamins and minerals
© 2012 John Wiley & Sons, Inc. All rights reserved.
Whole grains vs. refined grains
© 2012 John Wiley & Sons, Inc. All rights reserved.
Enrichment
Legislation requires the fortification of grains with some of the nutrients removed during processing
© 2012 John Wiley & Sons, Inc. All rights reserved.
Enrichment
© 2012 John Wiley & Sons, Inc. All rights reserved.
Empty calories
Refined sugars contain calories but lack fiber and other nutrients
Sugars from whole foods such as fruit and vegetables are more nutrient dense
© 2012 John Wiley & Sons, Inc. All rights reserved.
Empty calories
© 2012 John Wiley & Sons, Inc. All rights reserved.
Concept check
How are whole grains and refined sugars similar and different?
How are hole grains and refined sugars important for your health?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Concept check
In a refined grain, which part remains?
a) Germb) Branc) Endospermd) All of the above
© 2012 John Wiley & Sons, Inc. All rights reserved.
CarbohydratesCarbohydrates
(CH2O) nC = carbo; H2O = hydrate
Complex
AnimalStorage
Simple
Polysaccharides (poly means many)
Disaccharide(di means two)
Monosaccharide(mono means one)
PlantStorage
PlantStructure
Starch
Glycogen
Fiber
Soluble Insoluble
Galactose
Glucose
Fructose
Lactose
Maltose
Sucrose
© 2012 John Wiley & Sons, Inc. All rights reserved.
Disaccharides vs. Monosaccharides
© 2012 John Wiley & Sons, Inc. All rights reserved.
Complex carbohydratesExcess glucose is linked together for storage
Glycogen: storage in animal skeletal muscles and the liver
Starch: storage in plants
Fiber: a different type of bond links glucose molecules to make plant support structures
Humans cannot break this type of bond
© 2012 John Wiley & Sons, Inc. All rights reserved.
Complex carbohydrates
Glycogen
Starch
Fiber
© 2012 John Wiley & Sons, Inc. All rights reserved.
Excess glucose in animalsGlycogen: limited storage polymer of glucose in skeletal muscles and liver
Once glycogen storage capacity reached then glucose must be converted into fat
Fat: unlimited storage in adipose tissue
© 2012 John Wiley & Sons, Inc. All rights reserved.
Complex carbohydrates
© 2012 John Wiley & Sons, Inc. All rights reserved.
Photosynthesis
CO2 + H2Ocarbon + waterdioxide
Starch
Fiber
C6H12O6 + O2
glucose + oxygen
sunlightenergy
© 2012 John Wiley & Sons, Inc. All rights reserved.
Photosynthesis
© 2012 John Wiley & Sons, Inc. All rights reserved.
Soluble fiber vs. insoluble fiber
Soluble fiber:
Dissolves in water
Partially digested by bacteria in large intestine
Helps lower cholesterol
Examples: pectins, gums, & some hemicelluloses
© 2012 John Wiley & Sons, Inc. All rights reserved.
Soluble fiber vs. insoluble fiber
Insoluble fiber:
Does not dissolve in water
Not digested by bacteria in large intestine
Examples: cellulose, some hemicelluloses, & lignin
© 2012 John Wiley & Sons, Inc. All rights reserved.
Soluble fiber vs. insoluble fiber
© 2012 John Wiley & Sons, Inc. All rights reserved.
What are similarities and differences between:
Glucose and maltose?
Maltose and starch?
Starch and fiber?
Starch and glycogen?
Glucose and glycogen?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Concept check
Amylase breaks down starch into which disaccharide?
a) Glycogenb) Maltosec) Glucosed) Sucrose
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrate digestion
© 2012 John Wiley & Sons, Inc. All rights reserved.
Lactose intoleranceLow levels of small intestine enzyme lactase
The disaccharide lactose cannot be broken down into monosaccharides
Lactose passes into the large intestines where it is digested by bacteria
Symptoms: gas, abdominal distension, cramping, diarrhea
Obtain calcium from: tofu, legumes, dark green vegetables, canned salmon and sardines, calcium-fortified foods, calcium supplements, lactase-treated milk
© 2012 John Wiley & Sons, Inc. All rights reserved.
Lactose intolerance
© 2012 John Wiley & Sons, Inc. All rights reserved.
Indigestible carbohydrates
Fiber: not broken down by human enzymes
Oligosaccharides: 3–10 sugar units; some are not broken down by human enzymes
Resistant starch: natural structure of the grain protects the starch molecules or cooking and processing alter digestibility
Examples: legumes, unripe bananas, and cold cooked potatoes, rice, and pasta
© 2012 John Wiley & Sons, Inc. All rights reserved.
Indigestible carbohydrates
© 2012 John Wiley & Sons, Inc. All rights reserved.
Indigestible carbohydrates
© 2012 John Wiley & Sons, Inc. All rights reserved.
Glycemic index vs. load vs. response
Glycemic index: ranking of how a food affects blood glucose relative to an equivalent amount of carbohydrate from a reference food, such as white bread or pure glucose
Examples: white bread = 100, kidney beans = 25
© 2012 John Wiley & Sons, Inc. All rights reserved.
Glycemic index vs. load vs. response
Glycemic load: compares the effect of typical portions of food on blood glucose
Glycemic response: measures how quickly and how high blood glucose levels rise after carbohydrate consumption
© 2012 John Wiley & Sons, Inc. All rights reserved.
Glycemic index
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrate functions
Energy!
Lactose: used by nerve cells and to make milk
Ribose & deoxyribose: in DNA & RNA
Ribose: in B vitamin riboflavin
Cell membrane signaling
Cushioning and lubrication
© 2012 John Wiley & Sons, Inc. All rights reserved.
Insulin vs. glucagon
Increasedblood
glucose
Insulin secretion
Glucose taken
into cells
Decreasedblood
glucose
Decreasedblood
glucose
Glucagonsecretion
Glucose released from liver
Increasedblood
glucose
© 2012 John Wiley & Sons, Inc. All rights reserved.
Insulin vs. glucagon
© 2012 John Wiley & Sons, Inc. All rights reserved.
Digestion & cellular respiration
CO2 + H2O + ATPcarbon + water + energydioxide
Starch
C6H12O6 + O2
glucose + oxygen
Maltoseamylase
amylase
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrate metabolism
Pyruvate(3 carbons)
CellularRespiration
Lactic Acid Fermentation
2 ATPper glucose
2 ATPper glucose
32-36 ATPper glucose32-36 ATPper glucose
Carbon dioxide
Lacticacid
Glycolysis
Glucose(6 carbons)
CytosolCytosol
Anaerobic(without oxygen)
Anaerobic(without oxygen)
MitochondriaMitochondria
Aerobic(requires oxygen)
Aerobic(requires oxygen)
© 2012 John Wiley & Sons, Inc. All rights reserved.
Cellular respiration
© 2012 John Wiley & Sons, Inc. All rights reserved.
Protein & fat breakdown
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ketones
Ketones or ketone bodies = acidic molecules produced by fat breakdown when carbohydrates are not available to cells
Heart, muscle and kidneys use for energy
Brain adapts after 3 days to use ketones
Produced with starvation, low-carb diets, diabetes
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ketones
Ketosis: increased ketones in blood
Ketoacidosis: acidic blood from increased ketones
© 2012 John Wiley & Sons, Inc. All rights reserved.
Concept check
Which hormone is secreted when blood glucose is low?
a) Insulinb) Glycogenc) Ketonesd) Glucagon
© 2012 John Wiley & Sons, Inc. All rights reserved.
THINK about this – then share within a PAIR – then SHARE with the class
What do you know about diabetes?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitusDiseases characterized by high blood glucose
Type I: decreased insulin secretion
Autoimmune destruction of insulin-secreting cells in the pancreas
Type II: insulin resistance
Gestational: first observed during pregnancy
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus signs & symptoms
High blood glucose since insulin does not signal cells to take up glucose
Causes weight loss since the body breaks down fat
Causes increased hunger
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus signs & symptoms
Increased glucose in urine
Water tries to dilute glucose causing increased excretion of water causing dehydration and thirst
Blurred vision
Water tries to dilute glucose in the eye
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus complications
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus management
Control blood sugar levels
Limit carbohydrate intake
Increase whole grains, decrease refined sugars
Type I & some Type II patients need insulin injections
Type II patients often take oral drugs
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diabetes mellitus management
Exercise
Exercise and weight loss in Type II helps prevent, reverse, and manage the disease
Low saturated fat, low trans fat, low cholesterol
© 2012 John Wiley & Sons, Inc. All rights reserved.
What are similarities and differences between:
Insulin and glucagon?
Type I and Type II diabetes?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Hypoglycemia
Low blood sugar levels
Caused by:
Overmedication with insulin
Abnormal insulin or other hormone secretion or response
© 2012 John Wiley & Sons, Inc. All rights reserved.
Hypoglycemia
Fasting hypoglycemia: when a person has not eaten and usually has some other condition
Reactive hypoglycemia: too much insulin response after a high-carbohydrate meal
© 2012 John Wiley & Sons, Inc. All rights reserved.
Dental caries (cavities)
Bacteria in mouth digest carbohydrates and produce acid which damages tooth enamel
Increased risk:
Increased intake of sucrose and starchFrequent exposure
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrates & calorie intake
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrates & weight loss
© 2012 John Wiley & Sons, Inc. All rights reserved.
Debate
Should You Avoid High-Fructose Corn Syrup?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Nonnutritive (artificial) sweeteners
Replace sugar in the diet
Pros and cons:+ Decrease dental caries+ Control blood sugar− Associated with weight gain− Present in low nutrient density foods− Toxic at high doses
© 2012 John Wiley & Sons, Inc. All rights reserved.
Cardiovascular diseaseHigh-sugar diets increase blood lipids
High blood glucose damages blood vessels
Soluble fiber decreases cholesterol absorption and synthesis
High-fiber diets decrease blood pressure, weight, blood glucose, and heart disease
Diets high in fruits and vegetables increase fiber and protective antioxidants
© 2012 John Wiley & Sons, Inc. All rights reserved.
Soluble fiber & cholesterol
© 2012 John Wiley & Sons, Inc. All rights reserved.
Bowel health
High-fiber diets decrease:
Constipation (if adequate water is consumed)
Hemorrhoids (varicose veins in the anus and rectum)
Diverticula (outpouching of the large intestines)
Colon cancer??
© 2012 John Wiley & Sons, Inc. All rights reserved.
Diverticulosis
© 2012 John Wiley & Sons, Inc. All rights reserved.
Applications
What advice could you give to a loved on about carbohydrate consumption to decrease disease risk?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carbohydrate recommendations
Enough carbohydrate to meet glucose needs
Choosing types for health & disease prevention
RDA for carbohydrate =130 g/day
Acceptable Macronutrient Distribution Range for carbohydrate = 45–65% of total calorie intake
Adequate Intake for fiber = 38 g/day for men & 25 g/day for women
© 2012 John Wiley & Sons, Inc. All rights reserved.
How much carbohydrate do you eat?
© 2012 John Wiley & Sons, Inc. All rights reserved.
CalculateTotal calories = 3000
Total carbohydrates = 500 grams
Carbohydrates = 4 calories/gram
Fiber = 20 grams
Does this diet meet the RDA and AMDR for carbohydrate intake and the AI for fiber?
© 2012 John Wiley & Sons, Inc. All rights reserved.
Put it together
What is the percentage of calories from carbohydrate in a diet that provides 240 grams of carbohydrate and 2400 Calories?
a) 10b) 40c) 50d) 60
© 2012 John Wiley & Sons, Inc. All rights reserved.
Thinking it through
© 2012 John Wiley & Sons, Inc. All rights reserved.
Choosing carbohydrate wisely
2010 Dietary Guidelines and MyPlate:
increase whole grains, fruits and vegetables, and reduced-fat dairy products
limit foods high in refined grains and added sugars
Dietary Guidelines specifically recommend reducing intake of sugar-sweetened beverages
© 2012 John Wiley & Sons, Inc. All rights reserved.
Choosing carbohydrate wisely
MyPlate recommends for a 2000 calorie diet
6 oz of grains (half should be whole grains)
2 cups of fruit
21/2 cups of vegetables
© 2012 John Wiley & Sons, Inc. All rights reserved.
ChooseMyPlate.gov
© 2012 John Wiley & Sons, Inc. All rights reserved.
Interpreting food labels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Interpreting food labels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Interpreting food labels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Nutrition in the newsLow-carb diets
High-fructose corn syrup
Vending machines in schools
Artificial sweeteners
Taxes on sugar-sweetened beverages
© 2012 John Wiley & Sons, Inc. All rights reserved.
Checking student learning outcomes
How are whole grains and refined sugars similar and different? How do they contribute to health and disease?
How are types of carbohydrates similar and different?
What advice would you give to a loved one about carbohydrate consumption?