Chapter 5 Carbohydrates Objective 1. Describe the three types of carbohydrates

What comes to mind when you think of carbohydrates?

Carbohydrates carbohydrates: one of the six classes of nutrients that includes sugars, starches and fibers. The body’s main source of energy Except for the natural sugar in milk, nearly all carbohydrates come from plant sources.

Three Types of Carbohydrates Monosaccharides Disaccharides Polysaccharides

Carbohydrates are made of three common chemical elements: Carbon Hydrogen Oxygen These elements are bonded together to form saccharides, or sugar units These elements can be combined in several ways—the arrangement of the elements determines the type of sugar unit.

Monosaccharides Three Types of Monosaccharides Carbohydrates composed of single sugar units Are the smallest carbohydrate molecules Three Types of Monosaccharides Glucose Fructose Galactose

Monosaccharides Glucose Fructose Galactose Also known as blood sugar because it circulates in the bloodstream It is the body’s source of energy Fructose Has the sweetest taste Occurs naturally in fruits and honey Galactose Does not occur alone as a monosaccharide in foods It is bonded to glucose—together these 2 monosaccharides form the sugar in milk

Disaccharides Made up of two sugar units The body splits disaccharides into monosaccharides during digestion Three Types of Disaccharides Sucrose Maltose Lactose

Disaccharides Sucrose Sugar you use in recipes or add to foods Made up of one glucose molecule and one fructose molecule that are bonded together Examples: beet sugar, cane sugar, molasses and maple sugar

Disaccharides Lactose Maltose Found in milk Made up of one glucose molecule and one galactose molecule bonded together Serves as a source of energy for breastfed infants Maltose Made up of two glucose molecules that are bonded together Formed during the digestion of starch Can also be found in certain grains such as malt

All the mono-and disaccharides are collectively referred to as sugars. Note: All the mono-and disaccharides are collectively referred to as sugars.

Polysaccharides Carbohydrates that are made up of many sugars Must be broken down during digestion Types of Polysaccharides Fibers Starches

Polysaccharides Starch Storage form of energy in plants Made of many glucose molecules that are bonded together Examples: grain products (breads & cereals), starchy vegetables (corn, potatoes & legumes)

Found only in plant foods Examples: cellulose, gums and pectin Polysaccharides Fibers Polysaccharides that are make up the tough, fibrous cell walls of plants Found only in plant foods Human digestive enzymes cannot digest fibers, but bacteria in the digestive tract can break down some fibers—therefore, fibers provide almost no energy Examples: cellulose, gums and pectin

Simple vs. Complex Carbohydrates Simple Carbohydrates Mono-and disaccharides Foods that are high in simple sugars Examples: table sugar, candy, syrups and soft drinks

Simple vs. Complex Carbohydrates Polysaccharides Foods that are high in starch and fiber Examples: breads, cereals, rice, pasta & vegetables

Simple vs. Complex Carbohydrates Choosing food sources of complex carbohydrates and fewer sources of simple carbohydrates has health and nutrition benefits. Stayed tuned to learn why!!!

Hint…… Pop Quiz STUDY!!!!!!!!!!!!!

Objectives List the functions of carbohydrates. Explain how the body uses carbohydrates.

Review Take 5-10 minutes to review your notes from yesterday for a pop quiz!!!

Objectives List the functions of carbohydrates. Explain how the body uses carbohydrates.

Four Key Functions of Carbohydrates Provide energy Spare proteins Assist in the breakdown of fats Provide bulk in the diet

Functions of Carbohydrates: Provide Energy your body’s top priority is to provide enough energy for all cellular activities needed to sustain life carbohydrates are the preferred source of energy WHY? Because your body can use them efficiently as a fuel supply If your diet does not provide enough carbohydrates, your body will draw mainly upon proteins for fuel needs

Functions of Carbohydrates: Spare Proteins Background Information: if needed, your body can use proteins as an energy source your body is less efficient in using proteins if you eat too little carbohydrates, your body will use proteins for its major functions By eating adequate amounts of carbohydrates, you spare the proteins—this means you allow the proteins to be used for their more vital roles

Functions of Carbohydrates: Break Down Fats If the diet is too low in carbohydrates, the body cannot completely break down fats Incompletely broken down fats form compounds called ketone bodies Ketone bodies collect in the blood stream and become acidic—causing damage to cells and organs (ketosis)

Functions of Carbohydrates: Provide Bulk in the Diet fiber is the carbohydrate responsible for this task fiber helps promote normal digestion and elimination of body wastes fiber swells and makes you feel full fiber also slows the rate at which the stomach empties

Functions of Carbohydrates: Provide Bulk in the Diet Benefits of Fiber in the Diet: Prevent appendicitis Decrease risk of heart and artery disease Lower risk of colon cancer Controls diabetes soluble fiber: dissolves in water and develops a gel-like consistency—it helps lower blood cholesterol levels Example: oat bran, legumes insoluble fiber: does not dissolve in water—it helps reduce the risk of certain cancers Example: wheat bran and whole grains

How Your Body Uses Carbohydrates all carbohydrates must in the form of glucose for your cells to use them as energy sources to get them in this form, your digestive systems first breaks down all poly-and disaccharides into monosaccharides

How Your Body Uses Carbohydrates The monosaccharides are small enough to move across the intestinal wall into the blood They travel via the blood to the liver Any fructose and galactose in the blood is converted to glucose in the liver

Objectives 2. Use food labels to meet your carbohydrate needs. 1. Explain how your body uses carbohydrates. 2. Use food labels to meet your carbohydrate needs.

Pop Quiz Besides providing energy, name 1 function of carbohydrates. T/F All carbohydrates must in the form of glucose for your cells to use them as energy sources. T/F Your digestive systems does not have to break down all poly-and disaccharides into monosaccharides to use as energy. Monosaccharides travel via the blood to the _____. Any fructose and galactose in the blood is converted to _____ in the liver. Bonus: Why are carbohydrates the preferred source of energy?

How Your Body Uses Carbohydrates When the amount of glucose in the blood rises, a hormone called insulin is released from the pancreas. hormones: chemicals produced in the body and released into the bloodstream to regulate specific body processes insulin: helps the body decrease blood glucose back to a normal level

How Your Body Uses Carbohydrates Insulin triggers body cells to burn glucose for energy Insulin also causes muscles and the liver to store energy If the cells do not have immediate energy needs, they store the glucose—the glucose is converted to glycogen

How Your Body Uses Carbohydrates glycogen: the body’s storage form of glucose 2/3 is stored in your muscles for using during muscular activity 1/3 is stored in the liver for use by the rest of the body

How Your Body Uses Carbohydrates your liver can store only a limited amount of glycogen if you eat more carbohydrates than your body can immediately use or store as glycogen, your liver will convert the excess carbohydrates into fat Note: fat stores cannot be converted back into glucose

Meeting Your Carbohydrate Needs Two Categories of Sugars Sugars that occur naturally in foods Sugars added to foods at the table or during processing

Meeting Your Carbohydrate Needs: Sugars Sugars that occur naturally in foods Generally accompanied by other nutrients in foods—therefore they do not cause great concern among nutrition experts Examples: lactose in milks and fructose in fruit

Meeting Your Carbohydrate Needs: Sugars Sugars added to foods at the table or during processing Sometimes called refined sugars They come from such sources as sugar cane, sugar beets and corn Refined sugars function as more than sweetening agents—they are added to increase bulk or aid in browning refined sugars: carbohydrate sweeteners that are separated from their natural sources for use as food additives

Meeting Your Carbohydrate Needs: Sugars What foods are full of refined sugars? Many processed foods are high in added sugars—an excellent source of simple carbohydrates, but contributes no other nutrients to foods (increases calories without increasing nutrients). Reduced fat and fat-free products are high in added sugars **Manufacturers add sugar when removing fat

Meeting Your Carbohydrate Needs: Starches Starches are the preferred source of fuel for your diet. Your body can burn them efficiently for energy and they have greater satiety value than simple sugars. Many starchy foods are also excellent sources of vitamins, minerals and fiber.

Meeting Your Carbohydrate Needs: Fiber Determining fiber needs Take your age and add 5 to determine how many grams of fiber you should include in your diet daily Example: if you are 15 years old, 15+5= 20 grams of fiber per day Use this formula to age 20, then aim for 25 to 35 grams of fiber per day

Meeting Your Carbohydrate Needs: Fiber How to increase your fiber intake Choose whole grain products Use fiber supplements supplement: a concentrated source of a nutrient, usually in a pill, liquid or powder form Increase your intake of fiber slowly and drink plenty of water.

Using Food Labels to Meet Your Carbohydrate Needs Grams of sugars listed on a Nutrition Facts panel include both naturally occurring and added sugars—you need to do some further reading to identify foods that are high in refined sugars. Read list of ingredients on label—ingredients are listed in order of weight, with the most predominant ingredient being listed first. Only added sugars will be listed as ingredients. Check to see if more than one type of sugar is listed—these are both indications that a product is high in refined sugars.

Using Food Labels to Meet Your Carbohydrate Needs Examples of refined sugars brown sugar corn sweetener corn syrup dextrose fructose glucose invert sugar sucrose lactose maltose honey molasses sugar

Health Questions Related to Carbohydrates Are starchy foods fattening? Gram per gram, carbohydrates have the same amount of calories (4) as protein and less than half the calories of fat (9) People think starchy foods are fattening because how they are served Example: potato, pasta

Health Questions Related to Carbohydrates Is sugar a hazard to your teeth? There is a clear connection between sweets and dental caries (tooth decay). People who eat more sugar are likely to have a higher incidence of tooth decay HOWEVER starches can promote tooth decay also. Bacteria in the mouth feed on carbohydrates to form a sticky substance called plaque that clings to teeth—as the bacteria grows, they produce acid that eats away the protective tooth enamel, forming pits in the teeth. In time, these pits can deepen into cavities.

Health Questions Related to Carbohydrates The risk of tooth decay depends on two main factors: the type of food you eat when you eat it Sticky foods tend to cling to teeth making them more harmful than foods that are quickly swallowed and removed from contact with the teeth. Sugars and starches eaten between meals tend to be more harmful because they tend to remain in the mouth for longer periods.

Objective 1. Evaluate the role of carbohydrates in a variety of health issues.

Review What are supplements? What is another word for tooth decay? Your liver will convert excess carbohydrates into _____. What is the body’s storage form of glucose? What are supplements? What hormone is released when glucose levels in the blood rise? What foods are full of refined sugars? Why? What is another word for tooth decay?

Health Questions Related to Carbohydrates Does sugar cause hyperactivity? hyperactivity: a condition in which a person seems to be in constant motion and is easily distracted Researchers have conducted many studies but have found NO proof that consuming sugars causes behavior changes in most people. Sugar only gives children energy needed to fuel activity.

Health Questions Related to Carbohydrates Is sugar addictive? Some people seem to crave sweets all the time—some believe this type of craving qualifies as an addiction, or habitual need. Experiments have shown that if animals have a poorly balanced diet, they will eat excessive amounts of sugar. Research has shown people are born with a preference for sweet-tasting foods. Researchers think the need for sugar is more psychological than physiological—in other words, people eat sweets because they enjoy them, not because they are addicted to them.

sugar and starch convert to glucose which enters the bloodstream Diabetes diabetes mellitus: a lack of or an inability to use the hormone insulin sugar and starch convert to glucose which enters the bloodstream insulin regulates the blood glucose level by stimulating cells to pull glucose from the bloodstream when the body does not make enough insulin or fails to use insulin correctly, glucose builds up in the bloodstream

Diabetes Two types of diabetes Type I or insulin-dependent diabetes—the pancreas is not able to make insulin Occurs most often in children and young adults must use insulin injections Type II or non-insulin-dependent diabetes—body cells do not respond well to the insulin the pancreas makes More common Occurs in adults over 40 Can be controlled with diet

Numbness in legs, feet or fingers Diabetes Symptoms of Diabetes Excessive hunger and thirst accompanied by weakness, irritability and nausea Changes in eyesight Slow healing of cuts Drowsiness Numbness in legs, feet or fingers

the CNS depends on a constant supply of glucose from the blood Hypoglycemia hypoglycemia: a low blood glucose level an overproduction of insulin causes blood sugar to drop sharply 2-4 hours after eating a meal the CNS depends on a constant supply of glucose from the blood when sugar is too low, physical symptoms appear—sweating, shaking, headache, hunger and anxiety

Lactose Intolerance lactose intolerance: an inability to digest lactose, the main carbohydrate in milk This condition is caused by a lack of the digestive enzyme lactase, which is needed to break down lactose. People who are lactose intolerant may experience gas, cramping, nausea and diarrhea when they consume dairy products. Occurs more often among nonwhite populations and tends to develop as people age.