Chapter 4: Sugars, Starches and...

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


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?


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


Whole grains vs. refined grains


Enrichment

Legislation requires the fortification of grains with some of the nutrients removed during processing


Enrichment


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


Empty calories


Concept check

How are whole grains and refined sugars similar and different?

How are hole grains and refined sugars important for your health?


Concept check

In a refined grain, which part remains?

a) Germb) Branc) Endospermd) All of the above


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


Disaccharides vs. Monosaccharides


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


Complex carbohydrates

Glycogen

Starch

Fiber


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


Complex carbohydrates


Photosynthesis

CO2 + H2Ocarbon + waterdioxide

Starch

Fiber

C6H12O6 + O2

glucose + oxygen

sunlightenergy


Photosynthesis


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



Insoluble fiber:

Does not dissolve in water

Not digested by bacteria in large intestine

Examples: cellulose, some hemicelluloses, & lignin




What are similarities and differences between:

Glucose and maltose?

Maltose and starch?

Starch and fiber?

Starch and glycogen?

Glucose and glycogen?


Concept check

Amylase breaks down starch into which disaccharide?

a) Glycogenb) Maltosec) Glucosed) Sucrose


Carbohydrate digestion


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


Lactose intolerance


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






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


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


Glycemic index


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


Insulin vs. glucagon

Increasedblood

glucose

Insulin secretion

Glucose taken

into cells

Decreasedblood

glucose

Decreasedblood

glucose

Glucagonsecretion

Glucose released from liver

Increasedblood

glucose


Insulin vs. glucagon


Digestion & cellular respiration

CO2 + H2O + ATPcarbon + water + energydioxide

Starch

C6H12O6 + O2

glucose + oxygen

Maltoseamylase

amylase


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)


Cellular respiration


Protein & fat breakdown


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


Ketones

Ketosis: increased ketones in blood

Ketoacidosis: acidic blood from increased ketones


Concept check

Which hormone is secreted when blood glucose is low?

a) Insulinb) Glycogenc) Ketonesd) Glucagon


THINK about this – then share within a PAIR – then SHARE with the class

What do you know about diabetes?


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


Diabetes mellitus


Diabetes mellitus


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


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


Diabetes mellitus complications


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


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


What are similarities and differences between:

Insulin and glucagon?

Type I and Type II diabetes?


Hypoglycemia

Low blood sugar levels

Caused by:

Overmedication with insulin

Abnormal insulin or other hormone secretion or response


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


Dental caries (cavities)

Bacteria in mouth digest carbohydrates and produce acid which damages tooth enamel

Increased risk:

Increased intake of sucrose and starchFrequent exposure


Carbohydrates & calorie intake


Carbohydrates & weight loss


Debate

Should You Avoid High-Fructose Corn Syrup?


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


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


Soluble fiber & cholesterol


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??


Diverticulosis


Applications

What advice could you give to a loved on about carbohydrate consumption to decrease disease risk?


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


How much carbohydrate do you eat?


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?


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


Thinking it through


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


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


ChooseMyPlate.gov


Interpreting food labels






Nutrition in the newsLow-carb diets

High-fructose corn syrup

Vending machines in schools

Artificial sweeteners

Taxes on sugar-sweetened beverages


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?

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Chapter 4: Sugars, Starches and...

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