Chapter 7- Explain the origin of dietary carbohydrates. - Categorize the different carbohydrates as either mono- , di- or polysaccharidesMonosaccharaides(one sugar): Fructose, glucose, galactose Disaccharides (two sugars): Sucrose (glucose and fructose), Maltose (glucose and galactose), Lactose (Galatose and glucose). Polysaccharides: long chains of monosaccharides chained together.1. Starch – straight or branched chains of glucose like rice, pasta, bread, and potatoes. 2. Fiber – not digestable, but important (no ezyme to digest)Dietary fiber – found naturally in foodsFunctional fiber – Added to food for digestive benefit Psyllium added to cerealDietary and Functional – total fiber you eatSome foods can be both dietary and functional ex: pectin to yogurt (texture) and in citrus fruitsSoluable fiber – dissolves in water, viscous Can have thickening propertiesFermented in large intestine by bacteriaInsoluable fiber – doesn’t dissolve in water, branflakesLess readily fermented by bacteria Fiber and solubility are not exact effects Soluable fiber generally moves slower through tract and can have laxative effect in absorbing H20Insoluable fiber generally moves rather fast Humans store limited amounts, important source of glucose Can’t access glycogen in meat and poultry, breaks down when animal die.- Identify carbohydrate storage both in plants and animalsAnimals store carbohydrates as glycogen in the liver and muscles. Plants store them as starch. Amylose is a straight chain and amylopectin is a branched chain. - Explain the dietary differences between whole and enriched grains3 parts of single kernel of grain Bran (outer shell) - rich in fiber, B vitamins phytochems, minerals (Chromium and zinc)Germ (seed) – nutritional powerhouse. Vitamin E, heart –healthy fats, phytochemicals, B vitamins.Endosperm (starchy part) – Protein, B vitamins, some fiber (not as much as bran) Enriched grains attempt to restore some of the nutrients lost in refinement by adding back folic acid, thiamin, niacin, riboflavin and iron. Improves nutritional quality, fiber still lostWhole grains – whole wheat, brown rice, oatmeal. Contain all three parts of kernel. 3 servings daily recommended. It may reduce risk of heart disease, stroke, and diabetes. - Describe lactose intolerancePeople without enzyme lactase cannot digest lactose.Lactose maldigestion: natural part of aging process. It is the inability to absorb the milk sugar lactose properly due to a decrease in the amount of the enzyme lactase in your digestive tract. 25% americams and 75% of aduls wordlide do not digest lactose well.Europe, central Africa, Middle East are less likely to have it. Dairy products provide over 70% calcium needed.Lactose intolerance: severe lactose deficiency. Undigested lactose draws water into digestive tract causing diarrhea. Bacteria ferment lactose to produce gases. Bloating gas, cramps. Not the same as milk allergy. Some dairy foods better tolerated. Whole easier than skim. Hard aged cheeses easier. Yogurt better. - Describe carbohydrate digestion, where chemical digestion begins and is completedChemical digestion of carbohydrates begin in the mouth. Salivary amylase intakes hydrolysis in the mouth. Breaks down starch into maltose (disaccharide) no carbohydrate digestion in stomach. Hydrochloric acid in stomach destroys salivary amylase. Chemical digestion mostly occurs in the small intestine. Pancreatic amylase is produced in the pancreas and secreted into small with the enzyme, salivary amylase, during a hydrolysis. Breaks starch down to maltose in the small intestine. Disaccharides to monosaccharide. Disaccharide digestion – Intestinal cells make disaccharides enzymes – sucrose, lactase, maltase.Disaccharides digestion takes place on surface of brush board of small intestine. Hydrolyzed into monosaccharide. Which are transported into enterocytes. - Identify the two hormones that control blood glucose and describe their function and originInsulin – released by pancreas to lower blood glucose level. Directs glucose into cells and determines whether it will be used immediately as energy or stored for later use. If amount of glucose in blood exceeds body’s immediate energy needs, insulin directs it to be stored as glycogen. When glucose storage reaches limit, it stores as fat. Glycogen storage in muscles and liver. Glucagon – used when blood glucose levels dip too low. It directs release of glucose from stored glycogen in liver. Glucagon signals liver to start manufacturing glucose from noncarbohydrate sources (protein – Proteins have amino aids to generate glucose.Epinephrine – acts on liver and muscle cells to slow breakdown of glucose. Released from stress and low glucose levels. - Explain the consequences of not getting enough carbohydrates in the dietFasting – after 18 hours glycogen stores depleted. In burning fat without glucose, ketone bodies released which make blood acidic. Ketosis after 2 day fast. Protein breakdown from muscles and organs for glucose. Protein levels dangerously low. Chapter 8- Explain the difference between natural and added sugarNatural sugars: nutrient dense, lots of fruit. Fruit can contain more than 15% sugar by weight. It satisfies urge for sweetness and makes you full. Fruit also contains fiber and H20. Difficult to over consume calories from fruits and vegetables.Added sugars – can lower HDL levels. Empty calories. Honey and fructose not nutritionally superior to sucrose. #1 source added sugars in US = sweetened soft drinks. Recommended no more than 25% of total calories by DRI. Who recommends less than 10%. 30 tsp added sugar daily in USA. - Identify the ‘aliases’ of sugar on food labelsCorn sweetener, corn syrup, dextrose, sucrose, brown sugar, fructose, lactose, honey, syrup, high-fructose corn syrup, fruit juice concentrate invert sugar, raw sugar, malt syrup, maltose, molasses. - Explain where most of the sugar in the diets of Americans comes from33% soft drinks.Over 15% sugars / candy12-13% cakes/cookies/pies9% fuitades (lemondaes and fruit punch)6% grains (cinnamon toast, sweetened waffles) - Differentiate between the sugar substitutesSugar substitutes – as sweet or sweeter than sugar with less cals. Must be FDA approved. Polyols – sugar alcohols. Chem structure has added alcohol component. Sorbitol, mannitol Xylitol. Naturally found in plants and produced in gum and candies. May be sugar free but may not be calorie