Chapter 4 Exam 2 NUSC 1165

refined carbs

cause the greater glycemic response and rise in insulin, because they leave the stomach quickly

parts of the whole grain

endosperm- largest portion of grain kernel, contains starch and protein, some vitamins and minerals

bran- outermost layer, concentrated source of dietary fiber, vitamins, and minerals. loss of bran with refined carbs

germ- kernel base, embryo where sprouting takes place, source of vegetable oils and vitamin E

less than ____% of calories should come from added sugars, <___ calories or ___ teaspoons

10%, 200, 12

types of carbs

simple: mono and disaccharides

complex: oligosaccharides, glycogen, starch and fiber

glucose: blood sugar

galactose: component of lactose

fructose: fruit sugar

galactose

milk sugar

monosaccharide simple sugar

provides energy, brain health, cell signaling

disaccharides

simple carbs

maltose: glucose + glucose. formed when starch is broken down in the intestines

sucrose: table sugar. glucose + fructose. sugar cane, sugar beets, honey, maple syrup

lactose: milk sugar. glucose + galactose. occurs naturally in animal foods

photosynthesis

Sun → energy → CO2 + H2O → O2 and glucose → starch

hydrolysis

breaking down complex carbohydrates by adding water, disaccharides into monosaccharide

oxygen in disaccharides bonds to hydrogen bond to hydroxyl group

condensation reaction

one glycerol molecule binds with up to three fatty acid chains to form triglycerides

OH and H releases H2O

complex carbs

polysaccharides

oligosaccharides, starch, glycogen, fiber

oligosaccharides

some are formed during polysaccharide breakdown in the gut

beans, onions, bananas, garlic, artichokes (prebiotics)

not digested by enzymes

nutrient source for bacteria in the gut

starch

amylose: linear, unbranched chain of glucose units

amylopectin: highly branched, readily broken down by enzymes

potatoes, grains, rice

glycogen

storage form of carbs in animals comprised of highly branched chains of glucose molecules

stored in muscle and liver

carb loading

soluble fiber

pectins, gums, some hemicelluloses

broken down by intestinal microflora

may lower blood cholesterol

insoluble fiber

cellulose, some micro cellulose, lignin

cell wall in plants

wheat and rye bran

pectin

gels or jams used as a thickening agent

xanthan and locust bean gum

prevents solutions from separating. gravies, pudding, reduced fat dressing, frozen desserts

wheat bran

breads and muffins to increase fiber and reduce caloric contents

lactose intolerance

lactase available in minimal amounts

undigested lactose goes to the large intestine, which draws water and metabolized by bacteria producing acids and gas leading to symptoms

foods to help meet calcium needs for those with lactose intolerance

fortified plant milks, leafy greens, canned fish with bones, tofu, nuts/seeds, legumes

benefits of indigestible carbs (fiber, oligosaccharides, resistant starch)

increase amount of water or bulk in intestine

stimulate GI motility

promotes growth of healthy microflora

slows nutrient absorption

galactose role in the body

energy delivery

supports brain development

boosts mitochondrial function for energy production

role of fructose in the body

metabolizing it in the liver to convert into glucose for energy, stored as glycogen, or converted into fat

glycemic response

how quickly and how high blood glucose rises after carbs are consumed

affected by the amount and type of carbs eaten and amount of fat and protein in the food

glycemic load

index of glycemic response that occurs after consuming certain foods

glycemic index x grams of carbs per serving

20 or more = high

<11=low

feasting state

after a high carb meal

immediately after a meal, blood glucose level increases. insulin is released, stimulating the uptake and storage of glucose

increase of blood glucose in pancreas —> insulin —> glucose —> glucose —> muscle glycogen/glycogen in liver/glucose in fat storing cells —> blood glucose levels reduced

fasting state

when glucose levels are low in the blood

decreased blood glucose —> pancreas senses this, release glycogen —> promotes glucose release from the liver through glycogen or gluconeogenesis —> glucose released into blood

insulin

released in response to a high carb meal

a hormone secreted by the pancreas that allows the uptake of glucose by muscle and adipose tissue

stimulates protein and fat synthesis

stimulates synthesis of glycogen in liver and muscle

glucagon

hormone secreted by the pancreas that stimulates the breakdown of liver glycogen and the synthesis of glucose to increase blood sugar

glucagon signals liver cells to break down glycogen into glucose

stimulates gluconeogenesis

cellular respiration

the reactions that break down carbs, fats, and proteins in the presence of oxygen to produce carbon dioxide, water, and ATP

uses 6 molecules of O and 1 molecule of glucose

glycolysis

occurs in the cytoplasm of the cell. it is an anaerobic process

starting material: one 6-carbon molecule of glucose

end products: 2 pyruvate, 2 net ATP, and 2 NADH

acetylene CoA

occurs in the mitochondrial matrix. it’s an aerobic process

starting material: pyruvate

end products: acetyl CoA, CO2, and NADH

citric acid cycle

occurs in the mitochondrial matrix. aerobic metabolic pathways

electron transport chain

located on the inner mitochondrial membrane in eukaryotes

starting material: NADH and FADH_2, O2, and ADP

end products: ATP, H2O, NAD+, and FAD

starting and end products of gluconeogenesis

pyruvate, which is converted from lactate, amino acids, or glycerol

end product: glucose

why does gluconeogenesis occur during the fasting state?

when carbs are limited, glucose can be obtained from the breakdown of glycogen and the synthesis of new glucose by gluconeogenesis

ketones

molecules formed in the liver when the amount of carb is not sufficient to completely metabolize the two carbon units produced from fat breakdown

can be used as an energy source in tissues

why are ketones used in fasting state?

because the body has exhausted its glucose stores and must turn to fat for fuel

fatty acid breakdown without carbs

ketones are used for energy, excreted in urine, and accumulate in blood

used for energy in heart, muscle, kidney, and brain

type 1 diabetes

autoimmune destruction of insulin producing cells in pancreas, usually leading to absolute insulin deficiency

type 2 diabetes

when the body doesn’t produce enough insulin to keep blood glucose in the normal range

lifestyle and genetics

hypoglycemia

low blood glucose, accompanied by symptoms such as anxiety, sweating, tremor palpitations can result in overmedication of people with diabetes

treatment: carbs to raise blood sugar such as juice, honey, hard candy

reactive hypoglycemia

occurs in response to high carb foods

rise in glucose stimulates overproduction and release of insulin

glucose drops rapidly to abnormally low levels

fasting hypoglycemia

abnormal insulin secretion not related to food intake

related to hormone deficiencies, tumors, and excess alcohol intake

diverticulosis

pouches develop on the intestinal wall due to excessive pressure. accumulation of fecal matter in the pouches

diverticulitis

inflammation occurring in the pouches of the small intestine

low FODMAP diet

lean proteins, lactose free dairy, fruits like strawberries and oranges, veggies like carrots and cucumber, grains such as rice and oats

RDA for carbs

130g/day. minimum amount required to provide adequate glucose for brain

aspartame

equal

not heat stable

not recommended for those w PKU because phenylalanine hydrozylase is not available for use, so phenylalanine breakdown products will build up in the blood and the brain

PKU

inherited condition attributed to a defected gene, resulting in phenylalanine hydrozylase being unavailable for use

saccharin

sweet n low

not linked to cancer in humans, but in rats

stevia

truvia

used in baked foods to contribute to texture

sucralose

splenda

contains chlorine in its chemical structure

used in beverages and chewing gum

heat stable

sugar alcohols

sorbitol, mannitol, lactitol, and xylitol

no digested, absorbed, or metabolized

provides very little energy, which can cause GI stress

can be labeled as sugar free

can carry the health statement does not promote tooth decay

gum, candy, ice cream, baked goods