HUN 1201 Chapter 4

Types of monosaccharides

Glucose Fructose Galactose

Facilitated diffusion

how fructose in absorbed in the small intestine

HYDROLYSIS

hydro: water lysis: breaking a chemical reaction in which one molecule is split into two molecules, with hydrogen added to one and a hydroxyl group to the other this reaction commonly occurs during digestion

Protein intake

10-35%

Fat intake

20 - 35%

Percent of US packaged food containing sweeteners (mostly added)

75%

Acid-based balance

the equilibrium in the body between acid and base concentrations

Glycemic response

the extent to which a food raises the blood glucose concentration and elicits an insulin response

LEARN IT Identify the health benefits of, and recommendations for, STARCHES and FIBERS.

Clearly a diet rich starches and fibers supports efforts to control body weight and prevent heart disease, some cancers, diabetes, and GI disorders. For these reasons, recommendations urge people to eat plenty of whole grains, vegetables, legumes, and fruits - enough to provide 45 to 65 percent of the daily energy intake from carbohydrate.

All Monosaccharides

Contain 6 Carbon, 12 Hydrogen, & 6 Oxygen arranged differently

Protein foods

Contain almost NO carbohydrates however there are Two exceptions - NUTS provide a little starch and fiber along their abundant fat LEGUMES provide an abundance of starch and fiber (20 grams - with 1/3 from fiber)

Preventing HEART DISEASE

Diet rich in whole grains, legumes, vegetables, and fruits may protect against heart attack and stroke by lowering blood pressure, improving blood lipids, and reducing inflammation.

Maintaining GI health

Dietary fibers can help block the absorption of unwanted constituents. Water and insoluble fibers such as cellulose found in cereal brans, fruits, and vegetables increase stool weight, ease passage, and reduce transit time.

Dietary Carbohydrate Family

MONOSACCHARIDES - single sugars DISACCHARIDES - sugars composed of pairs of monosaccharides POLYSACCHARIDES - large molecules composed of chains of monosaccharides

Types of Disaccharides

Maltose (glucose + glucose) Sucrose (glucose + fructose) Lactose (glucose + galactose)

Simple Carbohydrates (the sugars)

Monosaccharides & Disaccharides

Preventing Diabetes

The soluble fibers found in high-fiber foods trap nutrients and delay their transit through the GI tract, glucose absorption is slowed, which helps to prevent glucose surge and rebound.

Herbal sweeteners (other high-intensity sweeteners)

Sweeteners derived from leaves and/or fruit that have been used for generations by the people of South America and China Luo han guo (Monk fruit) Stevia

Levulose

an older name for fructose

US adults receive this percent of their daily energy intake from added sugars

15%

Dietary Reference Intake recommends that added sugars should account for no more than what percent of a day's total energy intake

25%

DISACCHARIDES

3 pairs of monosaccharides linked together by glucose; put together and taken apart by similar chemical reactions: condensation and hydrolysis

On average, each person in the US consumes about how much sugar a day

30 teaspoons (120 grams)

Carbohydrate intake

45 - 65%

LEARN IT Explain how the body maintains its blood glucose concentration and what happen when blood glucose rises too high or falls too low.

Dietary cabohydrates provide glucose that can be used by the cells for energy, stored by the liver and muscles as glycogen, or converted into fat if intakes exceed needs. All of the body's cells depend on glucose; those of the brain and central nervous system are especially dependent on it. Without glucose, the body is forced to break down its protein tissues to make glucose and to alter energy metabolism to make ketone bodies from fats. Blood glucose regulation depends primarily on two pancreatic hormones: insulin to move glucose from the blood into the cells when levels are high and glucagon to free glucose from glycogen stores and release it in the blood when levels are low.

4.2

Digestion and Absorption of Carbohydrates

Added sugars (and alcohol) are considered

Discretionary kcalories

FDA recommends 28 grams of what for a 2000 kcalerie diet

Fiber (14 grams per 1000 kcalories)

Preventing Cancer

Fibers may help prevent colon cancer by diluting, binding, and rapidly removing potential cancer-causing agents from the colon. Soluble fibers also stimulate bacterial fermentation of resistant starch and fiber in the colon, a process that produces short-chain fatty acids that lower the pH. These small fat molecules activate caner-killing enzymes and inhibit inflammation in the colon.

Weight management

Foods rich in fiber tend to be low in solid fats and added sugars and therefore prevent weight gain and promote weight loss by delivering less energy per bite. In addition, as fibers absorb water from the digestive juices, they swell, creating feelings of fullness, lowering food intakes and delaying hunger.

Carbohydrate Absorption

Glucose can be absorb to some extent through the lining of the mouth, but for the most part nutrient absorption takes place in the small intestine Any remaining glucose along with galactose enter the cells lining the small intestinal wall by active transport Fructose is absorbed by facilitated diffusion

4.3

Glucose in the Body

4.5

Health Effects and Recommended Intakes of Starch and Fibers

4.4

Health Effects and Recommended Intakes of Sugars

Calculating total starch from Food Labels

Subtract the grams of fiber and sugar from the Total Carbohydrates

Various names of added sugars on food labels

Sucrose Invert Sugar Corn Sugar Corn Syrups and Solids High-Fructose Corn Syrup Honey

GLUCOSE

a monosaccharide; sometimes known as blood sugar in the body or DEXTROSE in food; one of the 2 sugars that make of a disaccharide; the unit from which polysaccharides are made almost exclusively glucose has a hexagonal shaped bond

POLYSACCHARIDES

a more complex sugar carbohydrate, containing MANY glucose units and, in some cases, a few other monosaccharides strung together poly: many

PHYTIC ACID

a nonnutrient component of plant seeds; when is binds with minerals needed by the body it prevents their absorption and all is excreted by the body

AMYLASE

a salivary enzyme that hydrolyzes amylose (a form of starch); is a carbohydrase; an enzyme that breaks down carbohydrates

Maple sugar

a sugar (mostly sucrose) purified from the concentrated sap of the sugar maple tree

Nectar

a sugary fluid secreted by plants to encourage pollination by insects

Malt Syrup

a sweetener made from sprouted barley and containing mostly maltose

Corn syrup

a syrup made from cornstarch that has been treated with acid, high temperatures, and enzymes to produce glucose, maltose, and dextrins. It may be dried and used as corn syrup solids.

SOLUBLE FIBERS

nonstarch polysaccharides that dissolve in water to form either a gel or can be digested by bacteria in the colon through fermentation; protect against heart disease and diabetes by lowering blood cholesterol and glucose levels

INSOLUBLE FIBERS

nonstarch polysaccharides that do not dissolve in water, do not form gels, or are not fermentable; promote bowel movements, alleviate constipation, and prevent diverticular disease

Alpha Cells

of the pancreas secrete glucagon in response to low blood glucose concentration

Sugars

simple carbohydrates composed of monosaccharids, disaccharides, or both

MONOSACCHARIDES

single sugars - glucose, fructose, and galactose

RESISTANT STARCHES

starches that escape the digestion and absorption in the small intestine of healthy people; similar to insoluble fibers this type of starch my support a healthy colon

Glycogen

fuels muscles for activity

Glucose

fuels nearly all of the brain's activities

Milk and Milk Products

Carbohydrate (12 grams - milk/yogurt), (6 grams - cheese) mostly Lactose

GRAINS

Carbohydrate (mostly starch) eat limited amounts of refined grains and choose whole-grain products which are typically high in fiber, nutrients, and antioxidants; help reduce risks for heart disease, diabetes, and certain cancers

FRUITS

Carbohydrates (15 grams) mostly sugars - including fructose

DRI states a person consuming 2000 kcalories a day should have 900 to 1300 kcalories from

Carbohydrates (225 to 325 grams)

Food labels (FDA) recommend 60% of a 2000 kcalories come from

Carbohydrates (300 grams)

VEGETABLES

Carbohydrates can come from starchy (15 grams) and nonstarchy (5 grams) vegetables

LEARN IT Summarize carbohydrate digestion and absorption

In the digestion and absorption of carbohydrates, the body breaks down STARCHES into the disaccharide - Maltose. Maltose and the other disaccharides (Lactose and Sucrose) from foods are broken down into monosaccharides, which are absorbed. The FIBERS help to regulate the passage of food through the GI tract and slow the absorption of glucose, but they contribute little, if any, energy. LACTOSE intolerance is a common condition that occurs when there is insufficient lactase to digest the disaccharide lactose found in milk and milk products. Symptoms are limited to GI distress. Because treatment requires limiting milk and milk products in the diet, other sources of riboflavin, vitamin D, and calcium must be included.

Lowering Cholesterol

Oatmeal, oat bran, barley, and legumes are foods rich in soluble fibers

Complex Carbohydrates (starches and fiber)

Polysaccharides

LEARN IT Describe how added sugars can contribute to health problems.

Sugars increase the risk of dental caries; excessive intakes displace needed nutrients and fiber and contribute to obesity when energy intake exceeds needs. A person deciding to limit daily sugar intake should recognize that not all sugars need to be restricted, just concentrated sweets, which are relatively empty of other nutrients and high in kcalories. Sugars that occur naturally in fruits, vegetables, and milk are acceptable. Alternative sweeteners may help to limit kcalories and sugar intake.

4.1

The Chemist's View of Carbohydrates

LEARN IT Identify the monosaccharides, disaccharides, and polysaccharides common in nutrition by their chemical structures and major food source.

The carbohydrates are made of carbon (C), oxygen(O), and hydrogen (H). Each of these atoms can form a specified number of chemical bonds: carbon forms 4, oxygen forms 2, and hydrogen forms 1. The three MONOSACCHARIDES (Glucose, Fructose, and Galactose) all have the same chemical formula (C6H12O6), but their structures differ. The three DISACCHARIDES (Maltose, Sucrose, and Lactose) are pairs of monosaccharides, each containing a glucose paired with 1 of the 3 monosaccharides. The sugars derive primarily from plants, except for lactose and its component galactose, which come from milk and milk products. Two monosaccharides can be linked together by a condensation reaction to form a disaccharide and water. A disaccharide, in turn, can be broken into its two monosaccharides by a hydrolysis reaction using water. The polysaccharides are chains of monosaccharides and include glycogen, starches, and dietary fibers. Both glycogen and starch are storage forms of glucose - glycogen in the body, and starch in plants - and both yield energy for human use. The dietary fibers also contain glucose ( and other monosaccharides), but their bonds cannot be broken by human digestive enzymes, so they yield little, if any, energy.

To increase carbohydrates in the diet, focus on

Whole grains Vegetables Legumes Fruits These foods are noted for their starch, fibers, and naturally occurring sugars.

Nutrient-dense foods which contain some added sugars

Whole-grain breakfast cereals Vanilla Yogurt

American Heart Association's recommended limit of added sugars

Women - 100 kcalories/day Men - 150 kcalories/day This is about 5% of a 2000/2500 calorie diet

CONDENSATION

a chemical reaction in which water is released as 2 molecules combine to form 1 larger product

Lactose intolerance

a condition that results from the inability to digest the milk sugar lactose; characterized by bloating gas, abdominal discomfort, and diarrhea; different from a milk allergy that is caused by an immune reaction to the protein in milk

LACTOSE

a disaccharide formed from 1 galactose and 1 glucose; the main carbohydrate of milk, and sometimes known as MILK sugar;

SUCROSE

a disaccharide formed from 1 glucose and 1 fructose; is the sweetest of the disaccharides (because of the fructose); is the natural sweetness found in fruits, vegetables, and grains; when refined from the juices of sugarcane and sugar beets, it becomes TABLE sugar

VISCOUS

a group of soluble fibers; a gel-like consistancy; like pectin from fruit, which is used to thicken jellies

FERMENTABLE

a group of soluble fibers; the extent to which the bacteria in the colon of the GI tract can break down and use the fibers;

Dental plaque

a gummy mass of bacteria that grows on teeth and can lead to dental caries (tooth decay) and gum disease.

EPINEPHRINE

a hormone of the adrenal gland that modulates the stress response; formerly called adrenaline when injected into the body epinephrine counteracts anaphylactic shock by opening up the airways and maintaining a heartbeat and blood pressure

GLUCAGON

a hormone secreted by special cells in the pancreas in response to LOW blood glucose concentration; this causes the release of glucose from the liver's glycogen stores

INSULIN

a hormone secreted by special cells in the pancreas in response to elevated blood glucose concentration; insulin controls the transport of glucose from the bloodstream into the muscle and fat cells

Lactose deficiency

a lack of the enzyme required to digest the disaccharide lactose into its component monosaccharides (glucose + galactose) can develop when the intestinal villi are damaged by disease, certain medicines, prolonged diarrhea, or malnutrition

PANCREATIC AMYLASE

a major carbohydrate-digesting enzyme released into the small intestine via the pancreatic duct and continues the process of breaking down the polysaccharides to shorter glucose chains and maltose

Glycemic index

a method of classifying foods according to their potential for raising blood glucose

Invert sugar

a mixture of glucose and fructose formed by the hydrolysis of sucrose in a chemical process; sold only in liquid form and sweeter than sucrose. Invert sugar is used as a food additive to help preserve freshness and prevent shrinkage

GALACTOSE

a monosaccharide, bonds with glucose as a disaccharide to form LACTOSE; hardly taste sweet at all

FRUCTOSE

a monosaccharide; sometimes known as FRUIT SUGAR or LEVULOSE; the sweetest of the sugars and is found abundantly in fruits, honey, and saps fruct: fruit fructose has a pentagonal shaped bond the source of high-fructose corn syrup

High-fructose corn syrup (HFCS)

a syrup made from cornstarch that has been treated with an enzyme that converts some of the glucose to the sweeter fructose; made especially for use in processed foods and beverages, where it is the predominant sweetener. With a chemical structure similar to sucrose, most HFCS has a fructose content of 42-55%, with glucose making up the remainder.

Ketone bodies

acidic compounds produced by the liver during the breakdown of fat when carbohydrate is not available

Type 2 diabetes

adult on set diabetes; the more common type of diabetes in which the cells fail to respond to insulin; usually accompanies obesity and results from insulin resistance (or too much glucose in the blood, causing too much insulin production) coupled with insufficient insulin secretion

Hypoglycemia

an abnormally low blood glucose concentration; can cause weakness, rapid heartbeat, sweating, anxiety, hunger, and trembling

OLIGOSACCHARIDES

an intermediate string of 3 - 10 monosaccharides strung together oligo: few

Ketosis

an undesirably high concentration of ketone bodies in the blood and unrine

DIETARY FIBERS

are the structural parts of plants and are found in all plant-derived foods; often described as NONSTARCH POLSACCHARIDES broken into 2 groups based on solubility

Dental caries

both naturally occurring and added sugars from foods and from the breakdown of starches in the mouth can contribute to tooth decay. Bacteria in the mouth ferment the sugars and, in the process, produce an acid that erodes tooth enamel causing dental caries or TOOTH DECAY

LACTASE

breaks lactose into 1 glucose and 1 galactose molecule

MALTASE

breaks maltose into 2 glucose molecules

SUCRASE

breaks sucrose into 1 glucose and 1 fructose molecule

MALTOSE

commonly known as MALT SUGAR; is a disaccharide made up of 2 glucose units; is produced when starch is broken down during carbohydrate digestion; also occurs during the fermentation process that yields alcohol

Carbohydrates

compounds composed of CARBON, OXYGEN, and HYDROGEN arranged as monosaccharides or multiples of monosaccharides; most have a combination of 1 carbon molecule to 1 water molecule; carbo = carbon, hydrate = with water

White sugar

granulated sucrose or "table sugar," produced by dissolving, concentrating, and recrystallizing raw sugar.

Kefir

digestible by most people with a lactose intolerance; a fermented milk product created by adding Lactobacillus acidophilus and other bacteria that break down lactose to glucose and galactose, producing a sweet, lactose-free product

FUNCTIONAL FIBERS

fibers that have been extracted from a food, manufactured and added to a food or used in supplements

Confectioner's sugar

finely ground, powdered sucrose; 99.9% pure

Heart Disease inducing

high carbohydrate diet rich in added sugars can alter the blood lipids to favor heart disease

Active transport

how the remaining glucose and galactose is absorbed by the body in the small intestine

Carbohydrate Digestion

in the mouth with the release of amylase in saliva; skips the stomach and really begins in the small intestine where most of the work of takes place when pancreatic amylase is released; the final step takes place on the outer membranes of the intestinal cells when specific enzymes step in to break down specific disaccharides: MALTASE- breaks maltose into 2 glucose molecules SUCRASE - breaks sucrose into 1 glucose and 1 fructose molecule LACTASE - breaks lactose into 1 glucose and 1 galactose molecule the only carbohydrates left are monosaccharides and are digested within 1-4 hours only fibers are left

Beta Cells

one of the several types of cells in the pancreas, secrete insulin in response to elevated blood glucose concentration

Diabetes

or diabetes mellitus; a metabolic disorder characterized by elevated blood glucose resulting from insufficient insulin, ineffective insulin, or both prediabetes - above normal, but below the diagnosis of this disease

Sugar alcohols

or polyols occur naturally in fruits and vegetables used in manufactured goods as a "sugar free" alternative, but they are not sugar free they do contain kcalories (.2-2.6 kcalories per gram) sometimes called nutritive sweeteners

Tagatose

poorly absorbed monosaccharide similar in structure to fructose; naturally occuring or derived from lactose

TOTAL FIBER

refers to the sum of the dietary fibers and functional fibers found in a food

Brown sugar

refined white sugar crystals to which manufacturers have added molasses syrup with natural flavor and color; 91-96% pure glucose

GLYCOGEN

stored form of energy (glucose) in the body; found in limited amounts in meat and not at all in plants, therefore it is not considered a food derived polysaccharide; is made of many glucose molecules linked together in highly branched chains; becomes available when a hormonal message to "release energy" is received by the liver or a muscle cell to send enzymes to attack the many branches of glycogen simultaneously

LIVER

stores 1/3 of the body's total glycogen and releases glucose into the blood stream as needed; regardless of the last time a person has eaten

Honey

sugar (mostly sucrose) formed from nectar gathered by bees. Composition and flavor vary, but honey always contains a mixture of sucrose, fructose, and glucose.

Turbinado sugar

sugar produced using the same refining process as white sugar, but without the bleaching and anticaking treatment. Traces of molasses give turbinado its sandy color.

Artificial Sweeteners

sugar substitutes that provide negligible , if any, energy; sometimes called nonnutritive sweeteners

Nonnutritive sweeteners

sweeteners that yield NO energy (or insignificant energy as in the case of aspartame

Nutritive Sweeteners

sweeteners that yield energy including both sugars and sugar alcohols

Harmful effects of excessive fiber intakes

temporary bouts of abdominal discomfort, gas, and diarrhea, and more seriously can obstruct the GI tract

Protein-sparing action

the action of carbohydrate (and fat) in providing energy that allows protein to be used for other purposes

SATIETY

the feeling of fullness and satisfaction that occurs after a meal and inhibits eating until the next meal; determins how much time passes between meals; sate: to fill

Raw sugar

the first crop of crystals harvested during sugar processing. Raw sugar cannot be sold in the United States because it contains to much filth (dirt, insect fragments, and the like). Sugar sold as "raw sugar" domestically has actually gone through more than half of the refining steps.

Type 1 diabetes

the less common type of diabetes in which the pancreas produces little to no insulin; usually results from an autoimmune destruction of the pancreatic beta cells

GLYCONEOGENESIS

the making of glucose from a noncarbohydrate source such as amino acids or glycerol gluco = glucose neo = new genesis = making

Dextrose

the name food manufacturers use for the sugar that is chemically the same as glucose; anhydrous dextrose is similar, differing primarily in the temperature of crystallization

1 out of 8

the number of people in the US population that exceeds the maximum DRI recommendation for added sugar intake

STARCHES

the stored from of energy (glucose) for PLANTS; polysaccharides composed of many glucose molecules; the human body hydrolyzes the ingested plant starch into glucose and then uses the glucose as the body needs; GRAINS are the richest food source of starch

Molasses

the thick brown syrup produced during sugar refining. Molasses retains residual sugar and other by-products and a few mineral; blackstrap molasses contains significant amounts of calcium and iron.