CARBOHYDRATES Learning Objectives: Understand the different classes of carbohydrates Understand the different classes of carbohydrates Understand the digestion and absorption of carbohydrates Understand the digestion and absorption of carbohydrates Learn about the function of carbohydrates in the diet, and how they relate to health issues Learn about the function of carbohydrates in the diet, and how they relate to health issues

WHAT ARE THE CARBOHYDRATES? Organic compounds that contain CARBON, HYDROGEN, and OXYGEN in the ratio of 1 carbon atom and 1 oxygen atom for every 2 hydrogen atoms Organic compounds that contain CARBON, HYDROGEN, and OXYGEN in the ratio of 1 carbon atom and 1 oxygen atom for every 2 hydrogen atoms Two Main Classes: Two Main Classes: SIMPLE (sugars) SIMPLE (sugars) COMPLEX (starches and fiber) COMPLEX (starches and fiber)

SIMPLE SUGARS MONOSACCHARIDES MONOSACCHARIDES Glucose (or Dextrose) Glucose (or Dextrose) Galactose Galactose Fructose Fructose

SIMPLE SUGARS DISACCHARIDES DISACCHARIDES Sucrose (glucose+fructose) Sucrose (glucose+fructose) Lactose (glucose+galactose) Lactose (glucose+galactose) Maltose (glucose+glucose) Maltose (glucose+glucose)

COMPLEX CARBOHYDRATES POLYSACCHARIDES Starch - long chains of glucose molecules in straight (AMYLOSE) or branching (AMYLOPECTIN) arrangement Starch - long chains of glucose molecules in straight (AMYLOSE) or branching (AMYLOPECTIN) arrangement Figure 4-8, page 106 Figure 4-8, page 106

COMPLEX CARBOHYDRATES POLYSACCHARIDES Glycogen – animal form of starch (highly branched and composed of multiple glucose molecules) Glycogen – animal form of starch (highly branched and composed of multiple glucose molecules)

COMPLEX CARBOHYDRATES FIBER – resembles starch, but cannot be digested FIBER – resembles starch, but cannot be digestedTYPES: Cellulose Cellulose Hemicellulose Hemicellulose Pectin Pectin Gums and Mucilages Gums and Mucilages Lignans (is fiber, but not a polysaccharide) Lignans (is fiber, but not a polysaccharide)

CLASSIFICATION of FIBER SOLUBLE – dissolve in water SOLUBLE – dissolve in water INSOLUBLE – cannot dissolve in water INSOLUBLE – cannot dissolve in water Table 4-3, page 123 Table 4-3, page 123 Daily recommendations? Daily recommendations?

B = 1 cup orange juice 2 scrambled eggs 1 slice white toast L =1 cup chicken noodle soup 1 cup iceburg lettuce 1 Tbsp blue cheese dressing D = 1 pork chop 1 cup white rice ½ cup canned corn 1 baked potato (no skin) 1 danish S = 1 oz. cheddar 4 saltine crackers

MOUTH - amylase MOUTH - amylase STOMACH STOMACH SMALL INTESTINE – pancreatic amylase, disaccharidases, maltase, sucrase, lactase SMALL INTESTINE – pancreatic amylase, disaccharidases, maltase, sucrase, lactase DIGESTION

all three travel to the liver through the portal vein; galactose and fructose are converted to glucose all three travel to the liver through the portal vein; galactose and fructose are converted to glucose

CARBOHYDRATES in the BODY USE OF GLUCOSE Energy – glucose is the primary fuel for most cells in the body. The brain MUST have glucose! Energy – glucose is the primary fuel for most cells in the body. The brain MUST have glucose! Sparing body protein – if glucose is scarce, the body will breakdown its own protein. Sparing body protein – if glucose is scarce, the body will breakdown its own protein. Preventing ketosis – with no carbohydrate, fat breakdown produces ketone bodies. Can lead to ketosis. Preventing ketosis – with no carbohydrate, fat breakdown produces ketone bodies. Can lead to ketosis. Storage as glycogen – liver stores are used to maintain blood sugar, while muscle stores are used to fuel activity. Storage as glycogen – liver stores are used to maintain blood sugar, while muscle stores are used to fuel activity.

REGULATING BLOOD GLUCOSE LEVELS Insulin – lowers blood glucose Insulin – lowers blood glucose Glucagon – raises blood glucose Glucagon – raises blood glucose Epinephrine – “fight-or-flight” hormone Epinephrine – “fight-or-flight” hormone

GLYCEMIC INDEX Classifies food or meals based upon their potential to raise blood glucose levels Classifies food or meals based upon their potential to raise blood glucose levels Expressed as a percentage of the response to a standard carbohydrate, usually white bread or pure glucose Expressed as a percentage of the response to a standard carbohydrate, usually white bread or pure glucose Useful? – decreased risk of NIDDM, heart disease, and colon cancer Useful? – decreased risk of NIDDM, heart disease, and colon cancer Useless? – complex, research may not support it Useless? – complex, research may not support it page 116 page 116

HIGH BLOOD SUGAR - Diabetes Type I – Insulin Dependent Diabetes Mellitus (IDDM) or Juvenile Onset Type I – Insulin Dependent Diabetes Mellitus (IDDM) or Juvenile Onset Type II – Non Insulin Dependent Diabetes Mellitus (NIDDM) or Adult Onset Type II – Non Insulin Dependent Diabetes Mellitus (NIDDM) or Adult Onset

HIGH BLOOD SUGAR - Diabetes RISK FACTORS Type I – genetics Type I – genetics Type II – genetics, >45 years old, overweight, sedentary, low HDL or high triglycerides, certain racial or ethnic groups, gestational diabetes Type II – genetics, >45 years old, overweight, sedentary, low HDL or high triglycerides, certain racial or ethnic groups, gestational diabetes

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HIGH BLOOD SUGAR - Diabetes CONSEQUENCES Peripheral vascular disease Peripheral vascular disease Deterioration of the eye Deterioration of the eye Kidney disease Kidney disease Progressive nerve damage Progressive nerve damage Heart disease Heart disease

CARBOHYDRATES in the DIET Recommendations Recommendations Current consumption Current consumption Increasing complex carbohydrate Increasing complex carbohydrate Moderating sugar intake Moderating sugar intake

CARBOHYDRATES and HEALTH - Sugar Sugar and nutrient intake: empty calories Sugar and nutrient intake: empty calories Sugar and dental caries: ex. baby- bottle tooth decay Sugar and dental caries: ex. baby- bottle tooth decay

Sugar Substitutes Saccharine (Sweet & Low)0 kcals/g Saccharine (Sweet & Low)0 kcals/g Sucralose (Splenda)0 kcals/g Sucralose (Splenda)0 kcals/g Aspartame (Nutrasweet)4 kcals/g Aspartame (Nutrasweet)4 kcals/g

Sugar Replacers Isomalt2.0 kcal/g Lactitol2.0 kcal/g Maltitol2.1 kcal/g Mannitol1.6 kcal/g Sorbitol2.6 kcal/g “Sugar-Free” does not necessarily mean free of calories!

High Fructose Corn Syrup? High Fructose Corn Syrup? Produced by milling corn to produce corn starch, then processing that corn starch to yield corn syrup (almost entirely glucose), and then adding enzymes which change the glucose into fructose Produced by milling corn to produce corn starch, then processing that corn starch to yield corn syrup (almost entirely glucose), and then adding enzymes which change the glucose into fructose Are all sugars the same? Page 118 Are all sugars the same? Page 118

CARBOHYDRATES and HEALTH – Complex Carbohydrates A diet rich in complex carbohydrates lowers the risk of: Obesity Obesity Type II Diabetes Type II Diabetes Cancer Cancer Cardiovascular Disease Cardiovascular Disease Gastrointestinal Disorders Gastrointestinal Disorders

Compared to Whole Wheat, White Bread is Missing: 96% of Vitamin E 96% of Vitamin E 78% of Fiber 78% of Fiber 72% of Magnesium 72% of Magnesium 62% of Zinc 62% of Zinc 78% of Vitamin B6 78% of Vitamin B6 Plus Phytochemicals Plus Phytochemicals

How Does Soluble Fiber Reduce Cholesterol?

Two Ways… Enterohepatic Circulation of Bile (page 149 “Bile’s Routes”) Enterohepatic Circulation of Bile (page 149 “Bile’s Routes”) Bacterial by-products of fiber fermentation in the large intestine inhibit cholesterol synthesis in the liver Bacterial by-products of fiber fermentation in the large intestine inhibit cholesterol synthesis in the liver

Fiber Supplements Benefits? Benefits? Risks? Risks?