Chapter 5 - Carbohydrates

The chemical bonds between individual sugar units in fiver ________ digested by enzymes in the human GI tract

cannot be

Added Sugars

Any sugars added during food manufacturing, such as honey, syrups, and concentrated fruit and vegetable juices. Added sugars do not include sugars found naturally in foods

Most carbohydrates are composed of ______

Carbon, oxygen, and hydrogen

Condensation Reaction

Chemical reaction in which a bond is formed between 2 molecules by the elimination of a small molecule, such as water. The linking of 2 monosaccharides occurs in a condensation reaction

Which of the following actions help in the digestion of carbohydrates?

Chewing, Cooking

Disaccharide

Class of sugars, including lactose and sucrose, that are formed by the chemical bonding of 2 monosaccharides

Total Fiber

Combination of dietary fiber and functional fiber in a good; also called fiber

Sucrose

Common table sugar. Disaccharide composed of fructose bonded with glucose by an alpha bond

Oligosaccharides

Complex carbohydrates that contain 3 to 10 monosaccharides. The beta bonds in oligosaccharides cannot be broken down by our digestive enzymes, meaning they pass undigested into the large intestine where bacteria metabolize them, producing gas and other by-products

Metabolic Syndrome

Condition characterized by poor blood glucose regulation, hypertension, increased blood lipids, and abdominal obesity; usually accompanied by lack of physical activity; previously called Syndrome X.

Diverticulosis

Condition of having many diverticula in the large intestine; asymptomatic.

What may occur as a result of excessive straining during defecation?

Hemorrhoids, Diverticula

Hyperglycemia

High blood glucose, above 125 mg/100 ml (dl) of blood.

Insulin

Hormone produced by beta cells of the pancreas. Among other processes, insulin increases the synthesis of glycogen in the liver and the movement of glucose from the bloodstream into muscle and adipose cells

Diverticula

Pouches that protrude through the exterior wall of the large intestine. Can be caused by the high pressure of exertion, which may be caused by a diet lacking adequate fiber, causing one to exert excessive force during defecation

Carbohydrates Function

Primary fuel source for cells, especially the cells of the central nervous system and red blood cells. Muscles also rely on carbohydrates to fuel intense physical activity

Foods that are good sources of carbohydrate include peas, dried beans, and dairy. In these foods, the carbohydrate content is diluted with _____.

Protein and fat

Digestible Carbohydrates

Provide a primary source of energy as glucose, spare protein from use as an energy source, and prevent ketosis. Most of the digestible carbohydrates in our diet are broken down to glucose

Non-Nutritive Sweeteners

Provide no food energy. Includes tagatose, advantame, sucralose, stevia, monk fruit, aspartame, and more.

Glycemic Index (GI)

Ratio of the blood glucose response to a given food, compared with a standard (typically, glucose or white bread).

Chemical digestion of carbohydrate begins in the mouth through the action of

Salivary amylase

Lactose maldigestion that occurs from a specific cause, such as long-standing diarrhea, and results in a decline in lactase production is considered _____ lactose maldigestion

Secondary

Lactose maldigestion that occurs from a specific cause, such as long-standing diarrhea, and results in a decline in lactase production is considered ______ lactose maldigestion.

Secondary

Monosaccharides

Simple sugars, such as glucose, fructose, and galactose, that is not broken down further during digestion

Soluble fibers help to regulate blood glucose by ____

Slowing the absorption of glucose from the small intestine

Gums

Soluble fiber consisting of chains of galactose and other monosaccharides; characteristically found in exudates from plant stems

Mucilage

Soluble fiber consisting of chains of galactose and other monosaccharides; characteristically found in seaweed

Pectin

Soluble fiber containing chains of various monosaccharides; characteristically found between plant cell walls

Amylase

Starch-digesting enzyme from the salivary glands or pancreas. Amylase breaks down the starch into smaller polysaccharides (called dextrins) and disaccharides

Cellulose

Straight-chain polysaccharide of glucose molecules that is indigestible because of the presence of beta bonds; part of insoluble fiber

Sugar Alcohols

Sweeteners that are structurally related to sugars but provide less energy than monosaccharides and disaccharides because they are not well absorbed. Sugar alcohols are not easily metabolized by bacteria in the mouth and in large quantities, sugar alcohols can cause diarrhea.

Nutritive Sweeteners

Sweeteners that can be metabolized to yield energy. Includes, lactose, maltose, glucose, sucrose, and fructose

Glucose

The most abundant monosaccharide, contains 6 carbons. Also called dextrose. A primary source of energy in the body. Found in table sugar (sucrose) bound to fructose

In which part of the GI tract does a minor amount of carbohydrate digestion begin?

The mouth

Glycogen

The storage form of carbohydrate in humans and other animals; also contains many glucose units linked together with alpha bonds. The branched structure of glycogen allows it to be broken down quickly by enzymes in the body cells where it is stored. Liver and muscle cells are the major storage sites for glycogen

General Formula for Carbohydrates

(CH2O)n or Cn(H2O)n, where n represents the number of times the formula is repeated. For example, the chemical formula of glucose is C6H12O6, or (CH2O)6

The Dietary Guidelines for Americans recommend limiting added sugar to no more than _____ of total daily energy intake for those aged 2 and older.

10%

What percentage of Americans shows the signs of lactose maldigestion?

25%

How much energy does glucose provide per gram?

4 kcal

How many grams of carbohydrates is needed daily to prevent ketosis?

50-100 g/day

Galactose

6-carbon monosaccharide that forms a 6-membered ring with oxygen in the ring; an isomer of glucose. Consists of glucose joined to galactose by a beta bond

Approximately ______ of the world's population is lactose intolerant

75%

Recommended Intake of Carbohydrates

According to the RDA, adults need about 130 g/day of digestible carbohydrate to supply adequate glucose for the brain and central nervous system to prevent the partial replacement of glucose by ketone bodies as an energy source. The Food and Nutrition Board recommends 45-65% of total energy intake should be carbohydrates

Glycemic Load (GL)

Amount of carbohydrate in a food multiplied by the glycemic index of that carbohydrate. The result is then divided by 100.

Diabetic Ketosis

Develops when insulin production is inadequate or cells resist insulin action, thereby preventing glucose from entering body cells. Cells then rely on ketone bodies from the breakdown of fats for energy. The accumulation of these ketones in the blood results in a more acid pH, a condition called diabetic ketoacidosis, which is a very serious complication of untreated or poorly controlled diabetes

Maltose

Disaccharide made of 2 glucose molecules joined by an alpha bond

Hyperactivity ___ result from consuming a diet high in refined carbohydrates.

Does not

The primary function of carbohydrate in the diet is to provide

Energy

Lactase

Enzyme made by absorptive cells of the small intestine; digests lactose to glucose and galactose.

Maltase

Enzyme made by absorptive cells of the small intestine; digests maltose to 2 glucoses

Sucrase

Enzyme made by the absorptive cells of the small intestine; digests sucrose to glucose and galactose.

A diet excessive in ______ may decrease the absorption of essential minerals such as iron and zinc.

Fiber

Functional Fiber

Fiber added to foods that has been shown to provide health benefits

Dietary Fiber

Fiber in food

Soluble Fibers

Fibers that either dissolve or swell in water and are metabolized (fermented) by bacteria in the large intestine; include pectins, gums, mucilages; more formally called viscous fibers

Insoluble Fibers

Fibers that mostly do not dissolve in water and are not metabolized by bacteria in the large intestine. These include cellulose, some hemicellulose, and lignins; more formally called nonfermentable fibers

Gluconeogenesis

Generation (genesis) or new (neo) glucose from certain glucogenic amino acids

When blood glucose levels drop, the pancreas releases _____ to raise blood glucose levels:

Glucagon

Most digestible forms of carbohydrates are broken down to ________

Glucose

Lactose

Glucose bonded to galactose; found in milk and other dairy products

Carbohydrate Family

Includes sugar, starch, and fiber. Most forms are composed of carbon, hydrogen, and oxygen. Plants are the main source of carbohydrates - during photosynthesis, plants produce glucose by using carbon and oxygen from carbon dioxide in the air, hydrogen from water, and energy from the sun. Plants either store the glucose or transform it into starch, fiber, fat, or protein

Diverticulitis

Inflammation of the diverticula caused by acids by bacterial metabolism inside the diverticula

Lignin

Insoluble fiber made of a multi-ringed alcohol (noncarbohydrate) structure

Polysaccharides

Large carbohydrates containing from 10 to 1000 or more monosaccharide units; also known as complex carbohydrates. The polysaccharides include some that are digestible, such as starch, and some that are largely indigestible, such as fiber. Their digestibility is determined mainly by whether the glucose units are linked together by alpha or beta bonds

When a person does not consume enough dietary carbohydrates, the metabolism of fats is ____.

Less efficient

When a person does not consume enough dietary carbohydrates, the metabolism of fats is _______

Less efficient

Fasting Hypoglycemia

Low blood glucose that follows about a day of fasting.

Reactive Hypoglycemia

Low blood glucose that may follow a meal high in simple sugars, with corresponding symptoms of irritability, headache, nervousness, sweating, and confusion; also called postprandial hypoglycemia.

Hypoglycemia

Low blood glucose, below 50 mg/100 ml (dl) of blood.

Primary Lactose Intolerance

May occur in up to 75% of the world's population. Those who have Asian, African, or Latino/Hispanic backgrounds are more likely to experience lactose intolerance than Caucasians. Many are able to consume moderate amounts of lactose with little or no intestinal discomfort because bacteria in the large intestine break down the lactose

Fructose

Monosaccharide with 6 carbons that forms a 5-membered or 6-membered ring with oxygen in the ring; found in fruits and honey

Hemicellulose

Mostly insoluble fiber containing galactose, glucose, and other monosaccharides bonded together