NUTR 225 Ch. 4

• - One of three macronutrients
• - Sources include fruits and vegetables

• - Most abundant carbohydrate
• - produced by plants through photosynthesis

• - One or two molecules
• 1) Monosaccharides: contain only one molecule (glucose, fructose, galactose)
• 2) Disaccharides: contain two molecules (lactose, maltose, sucrose)

• Glucose + Galactose = Lactose (milk sugar)
• Glucose + Glucose = Maltose (starch molecules)
• Glucose + Fructose = Sucrose (sugar cane, beets, honey)

• Long chains of glucose molecules (polysaccharides)
• e.g.: starch, glycogen, most fibers

• Storage form of glucose in plants;
• - grains, legumes, and tubers

• Storage form of glucose in animals
• - stored in liver and muscles

• Forms the support structures of leaves, stems, and plants.
• 1) Dietary fiber: non-digestible part of plants (grains, rice, seeds, legumes, fruits)
• 2) Functional fiber: carbohydrate w/known health effects, which is extracted from plants and added to foods (cellulose, guar gum, pectin, psyllium)

• - Dissolves in water
• - Easily digested by bacteria in colon
• - Citrus fruits, berries, oats, and beans

• - Found in whole grains (wheat, rye, brown rice)
• - Promote regular bowel movements, alleviate constipation, reduce risk for diverticulosis

• 1) Energy
• - 4 kcal/g
• - Red blood cells only rely on glucose for energy
• - Prevents excessive ketones (can result in high blood acidity and ketoacidosis)

• 2) Fiber
• - May reduce risk of colon cancer and heart disease
• - Can enhance weight loss
• - Helps prevent hemorrhoids, constipation, diverticulosis

High-fiber diet = less cholesterol in blood

• -Mouth-> Chewing stimulates salivary amylase, which breaks down starch into maltose
• -Stomach-> Salivary amylase is destroyed; no carb digestion yet.
• -Pancreas-> Pancreatic amylase is secreted into small intestine
• -Small intestine-> Pancreatic amylase breaks down starch into maltose; Enzymes in small intestine break down disaccharides into monosaccharides; monos absorbed into blood stream
• -Liver-> Monos travel from blood stream to liver via portal vein, convert into glucose, transport to cell for energy; excess glucose is stored as glycogen in liver
• -Large intestine-> Some carbs pass into large intestine undigested; bacteria ferment carbs; remaining fiber is pooped out

• -Small intestine-> dietary carbs from stomach delivered into small intestine
• -Liver-> Glucose and other monos transported to liver; blood levels of glucose maintained for brain and other body cells
• -Muscle-> Glucose transported to muscle for energy expenditure

• - Hormone secreted by the pancreas that helps transport glucose from the blood into cells.
• - Stimulates the liver and muscles to take up glucose and convert it to glycogen

• -Hormone secreted by pancreas to stimulate breakdown of glycogen to glucose
• -Stimulates gluconeogenesis, the production of "new" glucose from amino acids.

• - Measure of a food's ability to raise blood glucose levels
• - Foods w/low glycemic index have more fiber, may reduce risk of heart disease, colon cancer, prostate cancer

• - RDA recommends 130g/day
• - 45-65% of daily calorie intake should be carbs
• - Focus on foods high in fiber and low in added sugars

• - Dental problems
• - increased levels of "bad cholesterol"
• - may contribute to obesity

Adequate Intake of fiber is 14g/1000kcal (25g women; 38g men)

• 1) Nutritive sweeteners: 4kcal/g (sucrose, fructose, honey, brown sugar)
• 2) Sugar alcohols: 2-3kcal/g
• 3) Non-nutritive sweeteners: little to no kcal/g

• Inability to regulate blood glucose levels
• -Three types: Type I, Type II, and gestational diabetes

1) Type I: frequent urination, unusual thirst, extreme hunger, unusual weight loss, extreme fatigue, irritability

2) Type II: Frequent infections, blurred vision, cuts/bruises slow to heal, tingling/numbness in hands or feet, recurring skin/gum/bladder infection, Type I symptoms

• - >10% of all cases
• - not enough insulin
• - high blood sugar levels
• - diagnosed in adults
• - may lead to kedoacidosis, coma, death

• - Develops progressively over time
• - unresponsive to insuline, impaired fasting glucose, pre-diabetes
• - Pancreas may become unable to produce insulin

• - Obesity, genetics, physical inactivity, poor diet
• - Metabolic syndrome (high waist circumference, high BP, high blood lipids/glucose)
• - Increased age, yet younger people and children are now commonly diagnosed