© 2007 thomson - wadsworth chapter 3 the carbohydrates: sugar, starch and fiber

© 2007 Thomson - Wadsworth

Chapter 3

The Carbohydrates: Sugar, Starch and Fiber


Ask Yourself

1. Fruit sugar (fructose) is less fattening than table sugar (sucrose).

2. Foods high in complex carbohydrate (starch and fiber) are good choices when you are trying to lose weight.

3. People with diabetes should never eat sugar.4. The primary role of dietary fiber is to provide

energy.5. The brain demands the sugar glucose to fuel

its activities.


Ask Yourself

6. Honey and refined sugar are the same as far as thebody is concerned.

7. Of all the components of foods that increase one’srisk of diseases, sugars are probably the biggesttroublemakers.

8. Breads that are brown in color have more fiber than white bread.

9. Some foods labeled sugar-free actually contain calorie bearing sugars.

10. Artificial sweeteners are safe to use in moderation.


Carbohydrate Basics

• The primary role of carbohydrates is to provide the body with energy (calories).

• Carbohydrates are the preferred fuel for the brain and nervous system.

• Carbohydrates are the ideal fuel compared to other alternatives:Less expensive than protein.High-fat diets are associated with chronic

disease.


Carbohydrate Basics

• Carbohydrates: compounds made of single sugars or multiples of them and composed of carbon, hydrogen, and oxygen atoms. carbo = carbon (C) hydrate = water (H2O)

• Complex carbohydrates: long chains of sugars (glucose) arranged as starch or fiber. Also called polysaccharides. poly = many saccharides = sugar unit

• Simple carbohydrates (sugars): the single sugars (monosaccharides) and the pairs of sugars (disaccharides) linked together.


Carbohydrate Basics

• Carbohydrate-rich foods are obtained almost exclusively from plants.Milk is the only animal-derived food

that contains significant carbohydrate.

• All carbohydrates are composed of single sugars, alone or in various combinations.


Simple Carbohydrates

• Glucose is made of water and carbon dioxide. Plants use energy

from the sun to synthesize it.

• The atoms in a glucose molecule can be rearranged by plants to form fructose, too.



• Single Sugars - Monosaccharides:Glucose: (GLOO-koce) the building block of

carbohydrate; a single sugar used in both plant and animal tissues as quick energy. A single sugar is known as a monosaccharide.

• mono = one

Fructose: (FROOK-toce) fruit sugar—the sweetest of the single sugars.

Galactose: (ga-LACK-toce) another single sugar that occurs bonded to glucose in the sugar of milk.



• Double Sugars - Disaccharides:Sucrose: (SOO-crose) a double sugar

composed of glucose and fructose. A double sugar is known as a disaccharide.• di = two

Maltose: a double sugar composed of two glucose units.

Lactose: a double sugar composed of glucose and galactose; commonly known as milk sugar.



Added Sugars:• Sugar cane and sugar

beets are purified to make sucrose.

• Food examples include white (table) sugar, brown sugar, powdered sugar.

• Sucrose is common in sweets.



• Enzymes: protein catalysts. A catalyst facilitates a chemical reaction without itself being altered in the process. (Proteins are

discussed in Chapter 5; digestive enzymes in Appendix A.)

• Lactose intolerance: inability to digest lactose as a result of a lack of the necessary enzyme lactase. Symptoms include

nausea, abdominal pain, diarrhea, or excessive gas that occurs anywhere from 15 minutes to a couple of hours after consuming milk or milk products.


Complex Carbohydrates

• Starch: All starchy foods are plant foods.

• Sources of starch include:Seeds such as grains, peas

and beans. Legumes including dried

beans, lentils and soybeans.

Root vegetables (yams) and tubers (potatoes).



• Starch: a plant polysaccharide composed of hundreds of glucose molecules, digestible by human beings.

• Polysaccharide: a long chain of 10 or more glucose molecules linked together; the chains can be straight or branched; another term for complex carbohydrates.Shorter carbohydrate chains composed of 3

to 10 glucose molecules are called oligosaccharides.



• Staple grain: a grain used frequently or daily in the diet. Examples include:Corn in MexicoRice in AsiaWheat in Canada,

Europe and USAMillet, rye, barley, and

oats



• Refined: refers to the process by which the coarse parts of food products are removed. For example, the

refining of wheat into flour involves removing three of the four parts of the kernel—the chaff, the bran, and the germ—leaving only the endosperm.


The Wheat Kernel: A Whole Grain

• Germ: the nutrient-rich and fat-dense inner part of a whole grain.

• Endosperm: provides energy; contains starch grains embedded in a protein matrix.

• Bran: the fibrous protective covering of a whole grain and source of fiber, B vitamins, and trace minerals.

• Husk: (chaff) the outer, inedible covering of a grain.


Complex Carbohydrates• Whole grain: refers to a grain that is milled in its

entirety (all but the husk), not refined. Whole grains include wheat, corn, rice, rye, oats, amaranth,

barley, buckwheat, sorghum, and millet; two others—bulgur and couscous—are processed from wheat grains.



• Enriched: refers to a process by which the B vitamins thiamin, riboflavin, niacin, folic acid, and the mineral iron are added to refined grains and grain products at levels specified by law.

• Fortified foods: foods to which nutrients have been added. Typically, commonly eaten foods are chosen for fortification with added nutrients to help prevent a deficiency of a nutrient (iodized salt, milk with vitamin D) or to reduce the risk of chronic disease (juices with added calcium).


Eat Well Be WellWhole Grains for Health

1. Count to Three2. Keep It Varied3. Check the Label



• Fiber: the indigestible residues of food, composed mostly of polysaccharides. The best known fibers are cellulose, hemicellulose, pectin, and gums. Comes from the supporting structures of plants:

leaves, stems and seeds. Cannot be broken down by human digestive

enzymes although some may be broken down by bacteria residing in the digestive tract.

Fiber has few if any calories because it is not digested.


Complex Carbohydrates• Insoluble

fiber includes the fiber types called cellulose, hemicellulose, and lignin.

• Insoluble fibers do not dissolve in water.

• Soluble fiber includes the fiber types called pectin, gums, mucilages, some hemicelluloses, and algal substances (for example, carageenan); soluble fibers either dissolve or swell when placed in water.Psyllium seed husk is

an ingredient in certain cereals and bulk-forming laxatives and contains both soluble and insoluble properties.


Complex Carbohydrates• Whole food: a food

that is altered as little as possible from the plant or animal tissue from which it was taken—such as milk, oats, potatoes, or apples. The more a food

resembles the original, farm-grown product, the more nutritious it is likely to be.


We are advised to increase our intakes of complex carbohydrates. Choose plenty of whole foods like this…

…and fewer foods like these—foods that no

longer resemble their original farm-grown

products.


Added Sugars: Use Discretion

• Choose and prepare foods with little added sugar (Dietary Guidelines).

• Choose most often the naturally occurring sugars (DRI).

• For those who meet their nutrient needs, maintain a “healthy body weight” and still need additional calories --maximum intake = 25% or less for added sugars (DRI).



• Discretionary calories--small amounts of added sugars allowed within MyPyramid calorie allowance: 3 tsp. for 1,600 calories 5 tsp. for 1,800 calories 8 tsp. for 2,000 calories 9 tsp. for 2,200 calories 12 tsp. for 2,400 calories

Consistently build yourdiet using nutrient-dense foods, low in added sugars



• Reduce the incidence of dental caries by practicing good oral hygiene and consuming sugar- and starch-containing foods and beverages less frequently (Dietary Guidelines).


How the Body Handles Carbohydrates

• Digestive system: the body system composed of organs and glands associated with the ingestion and processing of food for absorption of nutrients into the body.

• Digestion: the process by which foods are broken down into smaller absorbable products.

• Absorption: the passage of nutrients or substances into cells or tissues; nutrients pass into intestinal cells after digestion and then into the circulatory system (for example, into the bloodstream).



• Glycogen (GLY-co-gen): a polysaccharide composed of chains of glucose, manufactured in the body and stored in liver and muscle. As a storage form of glucose, liver

glycogen can be broken down by the liver to maintain a constant blood glucose level when carbohydrate intake is inadequate.


When a person eats, blood glucose rises. High blood glucose stimulates the pancreas to release insulin. Insulin serves as a key for entrance of blood glucose into cells. Liver and muscle cells store the glucose as glycogen. Excess glucose can also be stored as fat.


Later, when blood glucose is low, the pancreas releases glucagon, which serves as the key for the liver to break down stored glycogen into glucose and release it into the blood to raise blood glucose levels



• Insulin: a hormone secreted by the pancreas in response to high blood glucose levels; it assists cells in drawing glucose from the blood.

• Glucagon (glue-cuh-gon):a hormone released by the pancreas that signals the liver to release glucose into the bloodstream.



• Glycemic index (GI): a scale that ranks carbohydrate-containing foods by how much they raise blood glucose levels compared to a standard food such as glucose or white bread. The glycemic load (GL) is a measure of the extent to which blood glucose is raised by a given amount of carbohydrate-containing food.

• Glycemic effect: the effect of food on a person’s blood glucose and insulin response – how fast and high the blood glucose raises and how quickly the body responds by normalizing.


Diabetes

• Diabetes (dye-uh-BEET-eez): a disorder (technically termed diabetes mellitus) characterized by insufficiency or relative ineffectiveness of insulin, which renders a person unable to regulate the blood glucose level normally.Type 1 diabetesType 2 diabetesGestational diabetes (see Chapter 11)


Prevalence of Diagnosed Diabetes by State


Hypoglycemia & Diabetes

• Hypoglycemia (HIGH-po-gligh-SEEM-eeuh): an abnormally low blood glucose concentration—below 60 to 70 mg/100 mL.

• Ketosis: abnormal amounts of ketone bodies in the blood and urine; ketone bodies are produced from the incomplete breakdown of fat when glucose is unavailable for the brain and nerve cells.

• Hyperglycemia: an abnormally high blood glucose concentration, often a symptom of diabetes.


A Look at the Glycemic Effect of Foods


Check your diabetes risk at…

• http://www.diabetes.org/risk-test.jsp?WTLPromo=HOME_risktest&vms=207048605236

http://www.diabetes.org/risk-test.jsp?WTLPromo=HOME_risktest&vms=207048605236




Sugar and Health• Research studies have not shown a direct

link between sugar and obesity, diabetes, heart disease, hyperactivity in children or criminal behavior.

• Diluted naturally occurring sugars found in milk and fruits should not be confused with concentrated refined sugar foods, such as table sugar, honey, and corn syrup. These concentrated sweets should be used in moderation, so as not to displace needed nutrients.

• Empty-calorie foods: a phrase used to indicate that a food supplies calories but negligible nutrients.


Keeping a Healthy Smile

• Dental caries – decay of the teeth, or cavities• Dental plaque – a colorless film, consisting of

bacteria and their by-products, that is constantly forming on the teeth

• Periodontal disease – inflammation or degeneration of the tissues that surround and support the teeth

• Nursing bottle syndrome – decay of all the upper and sometimes the back lower teeth that occurs in infants given carbohydrate-containing fluids when they sleep, or to carry around and sip all day


• HOW DID YOU DO? The more often you choose the items listed above, the

higher your diet is likely to be in sugars.You may need to cut back on sugar-containing foods, especially those you checked as “3 to 5 times a week” or more.This does not mean totally eliminating these foods from your diet.


Fiber…

Check Your Diet for Fiber


Concerns with Artificial Sweeteners

• Does saccharin cause cancer?• Does aspartame cause headaches?• Aspartame and phenylketonuria

(PKU)


To reach the FDA’s limit, a 150-pound adult would have to consume about 19 12-ounce cans of diet soda pop or 97 packets of Equal.

A 40-pound child would have to consume four 12-ounce cans of diet soft drinks or 24 packets of Equal.


Artificial Sweeteners & Sugar Alcohols

• Splenda’s popularity• Artificial sweeteners and weight

loss• Sugar substitutes and tooth decay• Sugar-free chewing gum

© 2007 thomson - wadsworth chapter 3 the carbohydrates: sugar, starch and fiber

Documents

sugar glucose

sugar of milk

milk sugar

thomson wadsworth slide

sugar cane

sugar beets

refined sugar

simple carbohydrates