Nutrition Lecture Notes QUIZ 2 1 30 14 CARBOHYDRATES Carbs simple carbs n CH2O C6H12O6 all plant foods and milk monosaccharides C6H12O6 disaccharides Glucose sucrose glucose fructose maltose glucose glucose lactose glucose galactose reactions complex carbs polysaccharides glycogen fructose most sweet glucose galactose least sweet hydrolysis breakdown disaccharide into monosaccharide add water digestion dehydration rxn form dissacharide from monosaccharides take out H2O animal storage not considered dietary carb CHO negligible source long highly branched glucose chain o digestive enzymes attack ends stored in humans o liver uses glycogen to regulate blood glucose 1 3 o skeletal muscle glucose reservoir for strenuous muscle activity 2 3 body storage capacity 200 500 g starch fiber plant storage found in grains legumes tubers glucose mol s linked via dehydration rxns o amylase long unbranched chains o amylopectin branched chains structure in plants o vegetables fruits legumes whole grains indigestible linkages are different than starch two types based on solubility and hence actions within the body soluble fiber dissolves in water to form a gel pectins gums mucilages and some hemi celluloses found in citrus fruits legumes grains oat rye barley psyllium husk cholesterol lowering effects eta glucans found in oats barley claim soluble fiber and risk of chronic heart disease 3 g of soluble fiber daily from whole grain oat foods like honey nut cheerios in a diet low in sat fat and chol May reduce risk of heart disease Insoluble fiber Cellulose some hemi cellulose and lignins actually not CHO Commonly found in vegetable whole grains bran Absorbs water and increases bulk Increases GI motility reducing transit time through colon Benefits alleviate constipation lower risk of diverticulosis and hemorrhoids promotes colon health Also phytic acid Carb digestion Mouth salivary amylase Stomach effects of fiber Small intestine 1 4 hours pancreatic amylase sucrose maltase lactase Large intestine Attract H2O soften stool Fermentation by bacteria of some fiber produces Gas Few short chain fatty acids o Metabolized by cells of the colon for E and by liver Lactose intolerance Lactase activity declines w age Lactose intake available lactase can handle Bloating abdominal discomfort diarrhea Most handle up to 6 g lactose 1 2 cup w o symptoms Adaptation depends on bacteria Dietary change Manage don t restrict General strategies Continue calcium vitamin D riboflavin intake Spread intake throughout day Consume with other foods in a meal Increase intake of milk products gradually Yogurt with live bacteria appears to improve Lactaid Enzyme tablets drops Carb absorption Glucose and galactose active transport Fructose facilitated diffusion Travel to liver via portal vein Galactose and fructose metabolized converted to glucose Glucose mostly released into bloodstream for use by cells Glucose Provides E Protein sharing Preferred fuel in brain developing RBCs nervous system fetus placenta When carbs not available or during starvation Some amino acids can provide glucose to brain gluconeogenesis Fat metabolism and ketone bodies Incomplete break down of fat Alternative fuel source Can lead to ketosis Regulating blood glucose levels Insulin response to elevated levels Increase glucose uptake in cells Simulate glycogen production in liver muscle Stimulate conversion of extra glucose to fat Glucagon response to low levels Stimulate liver cells to break down glycogen Stimulate gluconeogenesis from protein in liver Epinephrine adrenaline Secreted by adrenal glands in response to sudden stress danger sympathetic hormone Similar to glucagon stimulates the breakdown of glycogen Diabetes and hypoglycemia Type 1 and type 2 Hypoglycemia Symptoms weakness rapid heartbeat sweating anziety hunger trembling Occurs in poorly managed diabetes Rare in healthy people o Switch to fiber rich carbohydrates o Consume adequate protein each meal o Smaller more frequent meals may help Glycemic response and glycemic index GI Effect of a food on blood glucose levels o low glycemic response slow absorption modest rise in blood glucose and a smooth return to normal Glycemic index o Incremental area under the glucose response curve 2 hrs after consumption of 50 g of a test food relative to that of white bread or glucose o Affected by type of carb cooking process and presence of fat dietary fiber o Glycemic load may be more important o Eating small frequent meals may offer similar metabolic advantages o Decrease risk of developing type 2 DM o Improve blood sugar control of diabetics 2010 Dietary Guidelines states that Consistent evidence shows that glycemic index and or glycemic load are not associated with body weight and do not lead to greater weight loss or better weight maintenance Recommended CHO intake RDA 1 years old minimum Based on average minimum amt of glucose used by the brain Pregnant 175 g d Lactating 210 g d 130 g d AMDR 45 65 225 325 g d for 2000 kcal Daily Value 60 of 2000 kcal d 300 g d Recommended fiber intake AI Based on level of intake that provides greatest risk reduction for heart disease 14 g 1000 kcal Age 19 50 y Men 38 g Women 25 g CHD Soluble fiber and cholesterol reduce risk of Coronary heart disease Daily Value 25 g No UL Diabetes Controls blood glucose levels GI Insoluble fiber asorbs water creastes softer stools and thus promotes GI health and fxn with lower risk of hemorrhoids constipation and improved health of colon muscle Obesity High fiber diet tends to pair with lower BMIs high fiber foods have low fat content more food for fewer calories Add fiber to diet Eat more whole grains f v legumes Substitute meat for legumes pinto navy black beans lentils Brown rice High fiber cereals 5g fiber serving Whole fruits not juice Eat fruit peel potato skin Increase gradually over several wks while drinking plenty of water Add fiber too quickly increased abdominal discomfort gas and bloating If don t consume enough water hard and compacted stools Keep intake reasonable 40 g d and mineral intake adequate Added sugars Don t consumer more than 25 of day s total E from added sugars 50 added sugar comes in sugar sweetened beverages Influenced by prevalence of high fructose corn syrup vs table sugar Bacteria ferment sugar producing acid that erodes tooth enamel causing dental caries Non sugary food helps remove sugar from tooth surfaces Milk and cheese help stimulate saliva production rinsing teeth and re Factors length of
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