Transcript Nutrition Now J. Brown
Chapter 3
The Carbohydrates: Sugar, Starch and Fiber © 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
Ask Yourself
6.
Honey and refined sugar are the same as far as the body is concerned.
7.
Of all the components of foods that increase one ’ s risk of diseases, sugars are probably the biggest troublemakers.
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.
© 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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 (H 2 O) 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.
© 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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. © 2007 Thomson - Wadsworth
Simple Carbohydrates
•
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.
© 2007 Thomson - Wadsworth
Simple Carbohydrates
•
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.
© 2007 Thomson - Wadsworth
Simple Carbohydrates
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.
© 2007 Thomson - Wadsworth
Simple Carbohydrates
• 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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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).
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Complex Carbohydrates
• • 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.
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Complex Carbohydrates
•
Staple grain:
a grain used frequently or daily in the diet. Examples include: Corn in Mexico Rice in Asia Wheat in Canada, Europe and USA Millet, rye, barley, and oats © 2007 Thomson - Wadsworth
Complex Carbohydrates
• 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.
© 2007 Thomson - Wadsworth
The Wheat Kernel: A Whole Grain • • • •
Germ:
the nutrient-rich and fat-dense inner part of a whole grain.
Endosperm:
matrix.
provides energy; contains starch grains embedded in a protein
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.
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•
Complex Carbohydrates
Whole grain:
entirety (all but the husk) , not refined.
refers to a grain that is milled in its Whole grains include wheat, corn, rice, rye, oats, amaranth, barley, buckwheat, sorghum, and millet; two others—bulgur and couscous—are processed from wheat grains.
© 2007 Thomson - Wadsworth
Complex Carbohydrates
• •
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:
with added calcium).
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 © 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Eat Well Be Well Whole Grains for Health
1.
2.
3.
Count to Three Keep It Varied Check the Label © 2007 Thomson - Wadsworth
Complex Carbohydrates
•
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.
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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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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).
© 2007 Thomson - Wadsworth
Added Sugars: Use Discretion
Consistently build your diet using nutrient dense foods, low in added sugars • 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 © 2007 Thomson - Wadsworth
Added Sugars: Use Discretion
• Reduce the incidence of dental caries by practicing good oral hygiene and consuming sugar and starch containing foods and beverages less frequently
(Dietary Guidelines).
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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:
bloodstream).
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 © 2007 Thomson - Wadsworth
How the Body Handles Carbohydrates
• 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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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.
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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 © 2007 Thomson - Wadsworth
How the Body Handles Carbohydrates
• •
Insulin:
the blood.
a hormone secreted by the pancreas in response to high blood glucose levels; it assists cells in drawing glucose from
Glucagon
(glue-cuh-gon):a hormone released by the pancreas that signals the liver to release glucose into the bloodstream.
© 2007 Thomson - Wadsworth
How the Body Handles Carbohydrates
• •
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.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
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 diabetes Type 2 diabetes Gestational diabetes (see Chapter 11) © 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Prevalence of Diagnosed Diabetes by State
© 2007 Thomson - Wadsworth
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:
glucose concentration, often a symptom of diabetes.
an abnormally high blood © 2007 Thomson - Wadsworth
A Look at the Glycemic Effect of Foods
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Check your diabetes risk at…
• http://www.diabetes.org/risk test.jsp?WTLPromo=HOME_risktes t&vms=207048605236 © 2007 Thomson - Wadsworth
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:
to indicate that a food supplies calories but negligible nutrients.
a phrase used © 2007 Thomson - Wadsworth
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 © 2007 Thomson - Wadsworth
• 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.
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Check Your Diet for Fiber
Fiber… © 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Concerns with Artificial Sweeteners
• • • Does saccharin cause cancer?
Does aspartame cause headaches?
Aspartame and phenylketonuria (PKU) © 2007 Thomson - Wadsworth
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. © 2007 Thomson - Wadsworth
Artificial Sweeteners & Sugar Alcohols
• • • • Splenda’s popularity Artificial sweeteners and weight loss Sugar substitutes and tooth decay Sugar-free chewing gum © 2007 Thomson - Wadsworth