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118 Cards in this Set
- Front
- Back
What type of fat is the most prevalent in our diet and in our body?
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triglycerides
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What are triglycerides composed of?
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Three fatty acid (C + H) molecules and One glycerol (3-C alcohol) molecule
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What are fatty acids composed of?
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C + H molecules
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What are three ways can fatty acids differ?
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Short-, medium-, or long-chain fatty acids
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What is the shape effect of a double bond?
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The fatty acid bends wherever there is a double carbon bond (point of unsaturation)
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The hydrogen atoms at the unsaturated region can be arranged in different positions
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Cis: same side of carbon chain
Trans: opposite sides of chain |
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Saturated fatty acids
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have hydrogen atoms surrounding every carbon in the chain. solid at room temperature, Predominant type in animal foods and coconut oil
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Monounsaturated fatty acids
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lack hydrogen atoms in one part (“one” double bond)
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Polyunsaturated fatty acids
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lack hydrogen atoms in multiple sites (“more than one” double bond)
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Define oxidation.
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Stable atom with even number of electrons loses an electron à unpaired electron or free radical
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Which fatty acids are most susceptible to oxidation?
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polyunsaturated fatty acids
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Define rancidity
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decomposition of fats, oils and other lipids by hydrolysis or oxidation, or both
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Oxidative stress:
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an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage
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Which conditions are associated with oxidative stress?
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Cancer, Heart disease, Diabetes, Arthritis, Cataracts, Macular degeneration, Kidney disease, Alzheimers disease, Senile dementia, Parkinson’s disease
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What are trans fats?
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Hydrogenated oils, Processed foods
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In what process are trans fats created?
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Hydrogenation
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What are dietary sources of trans fats?
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Fried foods, commercial baked goods, processed foods and margarine
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What fatty acids are trans fats similar to in structure and function?
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polyunsaturated
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What are essential fatty acids, and what is their function?
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Linoleic (omega-3) and alpha-linolenic (omega-6) acid are:
Incorporated into cell membranes, Precursors of longer-chain fatty acids, Converted into regulatory compounds called eicosanoids- blood pressure, platelet aggregation, immune response (intensity, duration of inflammation) |
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Define eicosanoids.
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regulatory compounds called eicosanoids- blood pressure, platelet aggregation, immune response (intensity, duration of inflammation)
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What is the differing effect of omega-3 and omega-6 eicosanoids?
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Omega-3: anti-inflammatory omega-6: pro-inflammatory
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How do you optimize your EPA availability?
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Direct intake of EPA/DHA
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Review slide on different fat/oil types. What are the major sources of each type at the top of the slide (different colors)?
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Omega-6, omega-3, monounsaturated, and saturated fats
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What are phospholipids and their main role?
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Are composed of glycerol backbone and two fatty acids + phosphate, Are soluble in water, Are manufactured in our bodies so not required in our diet, Important component of cell membranes
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What are sterols?
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Lipids containing multiple rings of carbon atoms, Manufactured in our bodies (2:3 of requirement) so not essential components of our diet, In animal foods
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How do fats enter the mucosal cells?
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micelle (fatty acids, monoglycerides, phospholipids, sterols)
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Which fats need to be transported by the lymphatic system?
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Long chain fatty acids
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What are the roles of fat?
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Energy - primary during rest; aerobic activity: after glycogen depletion; energy storage
Transporter of fat-soluble vitamins, Cell membrane structure, Nerve cell transmissions, Protection of internal organs, Insulation to retain body heat, Provides flavor and texture to foods, Contributes to satiety - more energy dense; takes longer to digest |
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What are chylomicrons?
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a water-soluble lipoprotein produced by cells lining the small intestine that is composed of triglycerides surrounded by phospholipids and proteins
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What are the other three lipoproteins, and what is their transport role?
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VLDL: very low density lipoprotein-transports endogenous lipids (triglycerides) to body tissues
LDL: low density lipoprotein-transports cholesterol to body cells HDL: high density lipoprotein- transports cholesterol from tissues back to the liver |
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What is atherosclerosis, and how does it begin?
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When arteries block from Deposition of fats, cholesterol, platelets, cellular debris, calcium begins from dysfunction of the heart or blood vessels
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What is the major blood lipid involved in the process of atherosclerosis?
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cholesterol
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What are the risk factors for atherosclerosis?
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Being overweight
Physical inactivity Smoking High blood pressure *High blood glucose/insulin Abnormal blood lipid profile *inflammatory conditions High blood *homocysteine Western dietary pattern - high intake of grain-fed meat, *simple carbohydrates |
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What is the effect of the different types of fatty acids on LDL and HDL?
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Saturated- Can raise *LDL, contribute to formation of plaques monounsaturated- Lower LDL cholesterol, raise HDL cholesterol polyunsaturated- Lower *LDL cholesterol
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Which fish are highest in the omega-3 fats, EPA and DHA?
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salmon
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What are the (2) special effects of EPA/DHA compared to ALA?
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Reduces *Blood Triglycerides
Raises *HDL cholesterol |
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Which fish (4) should be avoided or reduced due to mercury contamination?
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king mackerel, tilefish, *swordfish, shark
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What is the recommendation for fish consumption?
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Adults should eat fish *greater than or equal to 2X wk.
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What is the saturated fat, trans fat, and n-6/n-3 ratio recommendations for heart health?
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* less than 7% total calories from saturated fatty acids
‘Keep trans fatty acid consumption as low as possible (probably should be limited to <0.5% of daily kcals (~1g) 0.6 to 1.2% of total kcals for linolenic (ω3) fatty acids 5-10% of total kcals for linoleic acid (ω6) fatty acids |
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What are other dietary recommendations for heart health (antioxidants, etc.)?
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Increase *antioxidant intake to prevent LDL oxidation-nutrients, polyphenols, resveratrol
Increase fiber intake to 20-30 g/d, particularly soluble, to lower cholesterol Intake of 400 ug/d of *folate to keep blood *homocysteine levels low Maintain blood sugar / insulin in normal range to prevent increased blood *triglycerides Increase intake of plant sterols to lower blood cholesterol |
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lifestyle recommendations?
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Lowers *VLDL raises HDL
Improves *insulin sensetivity Helps maintain healthy weight and normal blood pressure Maintain healthy body weight |
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What are the three chemical groups of an amino acid?
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Glycine, leucine, aspartic acid
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Which amino acids are essential?
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Histidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
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What is the structure of a protein dictated by?
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DNA of a gene
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Define transcription
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mRNA leaves the nucleus and attaches itself to the ribosome
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translation
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mRNA binds with rRNA which signals tRNA to carry AA to mRNA from the cytoplasm which dictates the sequence
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mRNA
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the template for protein synthesis; the form of RNA that carries information from DNA in the nucleus to the ribosome sites of protein synthesis in the cell
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ribosomes
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attach to mRNA and move down it one codon at a time and then stop until tRNA brings the required amino acid; when it reaches a stop codon it falls apart and releases the completed protein molecule for use by the cell
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Primary structure
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- sequential order of amino acids
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Secondary structure
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- spiral shape due to chemical bonding between the amino acids
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Tertiary and quaternary structure
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- further folding into a unique 3-dimensional shape that may be globular or fibrous
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Define denaturation and its effect on protein function.
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Proteins uncoil and lose their shape, Protein function is lost
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What are agents of denaturation?
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Caused by heat, acid, base, enzymes, metals, alcohol, whipping/beating
Protein is denatured during digestion, Denatured enzyme cannot do its job, May occur during high fever or when blood pH out of normal range |
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Define limiting amino acid.
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Essential AA that is missing or in the smallest supply, slows down or halts protein synthesis
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Incomplete protein:
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does not contain do not contain all essential amino acids
Not sufficient for growth and health Considered a “low quality” protein |
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Complete protein:
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contains sufficient amounts of all 9 essential amino acids
Derived from animal and soy protein Considered a “high quality” protein |
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Mutual supplementation:
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two or more incomplete proteins eaten together to make a complete protein
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Complementary proteins:
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two or more foods that together supply all 9 essential amino acids for a complete protein
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What is the limiting amino acid in legumes?...in grains?
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Legumes: methionine
grains: lysine |
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Chemical score
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– compares amount of limiting amino acid in food with amount in reference food LAA / LAA in reference food
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Protein digestibility corrected amino acid score (PDCAAS)
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– adjusts for digestibility of source
Animal, soy, legumes, grains |
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Biological value
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– comparing amount of N retained with amount N consumed
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Protein efficiency ratio
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– compares weight gained by lab animal on test protein vs reference protein
Used in labeling infant foods |
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What is the RDA for protein? How do you calculate it?
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0.8 gram per body weight
Take ur weight divided by 2.2=protein needed daily |
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Why is amino acid supplementation unwise?
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can cause absorption imbalance, toxicity
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Name the functions of proteins.
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Cell growth, repair, maintenance
Enzymes and hormones *fluid and electrolyte balance- prevent edema *pH balance- side chains attract H Antibodies Nutrient transport and storage Energy source |
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What is the main role of carbohydrates in the body?
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SOURCE OF ENERGY IN BODY
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What are the general carbohydrate classifications?
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Simple-contain one or two molecules (sugars)
Complex- polysaccarides |
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Name the monosaccharides and which disaccharides they form in combination.
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Glucose, fructose, and galactose are the three most common monosaccharides
three most common disaccharides found in foods are lactose, maltose, and sucrose |
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Name the monosaccharides and which disaccharides they form in combination.
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Glucose, fructose, and galactose are the three most common monosaccharides
three most common disaccharides found in foods are lactose, maltose, and sucrose |
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What are food sources?
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White bread, soft drinks, cookies/cakes, sugars, syrups, jams, potatoes
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Define oligosaccharides. How are they digested?
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carbohydrates that contain 3 to 10 monosaccharides, most common found in raffinose and stachyose. fermented by bacteria that produce gases such as carbon dioxide, methane, and hydrogen.
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What are three polysaccharides?
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Starch, glycogen, and fiber
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Which are complex carbs?
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any carbohydrates with three or more monosaccharides
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What is glycogen, and where is it stored?
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Storage form of glucose in animals and stored in liver and muscles
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What is starch, and what are food sources?
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Storage form of glucose in plants…food sources include grains, legumes, and tubers
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What is resistant starch, and how is it digested?
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Resistant starch is due to high amylase content or accessibility to amylases –intact whole grains, legumes, unripe bananas, cooked cold starches – fermented by microflora
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What does total fiber refer to on a food label?
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Dietary + functional fiber…food labels only list dietary fiber
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What is functional fiber?
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Difficult to digest or nondigestible forms of carbohydrates that are extracted from plants or manufactured
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Which two hormones are mostly involved in blood sugar regulation, where are they produced, and what effect do they have in terms of blood sugar levels?
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Insulin-produced in beta cells of the pancreas, stimulates glucose transporters to help take glucose from the blood across the cell membrane
Glucagon- produced by alpha cells in pancreas, stimulates the liver to breakdown glycogen to glucose making glucose available to body cells |
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What other hormones affect blood sugar?
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Epinephrine and norepinephrine, cortisol, growth hormone
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Define gluconeogenesis. When does gluconeogenesis occur?
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Synthesis of glucose from non carbohydrate sources, occurs when there is an insufficient carbohydrate intake level
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Describe the glycemic index.
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Ranks food’s potential to raise blood glucose and insulin levels
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What is glycemic load?
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Amount of carbs in a food is multiplied by glycemic index…portion size how much your eating
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Ketosis
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- process by which fat breakdown during fasting states results in ketones
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Ketones
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- Substances produced during the breakdown of fat when carbohydrate intake is insufficient to meet energy needs. Provide an alternative energy source for the brain when glucose levels are low
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Ketoacidosis
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- A form of metabolic acidosis caused by elevated serum levels of ketone bodies
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How much carbohydrate is recommended daily to avoid ketosis?
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130 grams per day
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List the roles of fiber in reducing risk of disease.
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Fiber is important for movement for digestion
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Insufficient fiber can cause what disease condition?
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obesity, heart disease, and type 2 diabetes
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What are the possible effects of a diet high in simple carbohydrates?
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Dental caries, diarrhea, diabetes
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Which added sugar has increased the most in the last forty years?
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splenda
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Soluble fiber
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dissolves in water, viscous and gel-forming, fermentable. Bind with fatty acids. Associated with lower cholesterol, preventing glucose surge, sources are citrus fruits, berries, oats/oat bran, legumes, nuts
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Insoluble fiber
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- does not dissolve in water, nonviscous, nonfermentable. Promotes regular bowel movements due to greater gut motility sources: whole wheat, seeds, legumes, fruits, vegetables
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What factors influence a food’s ranking in terms of the glycemic response?
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Food’s fat, fiber, acid and type of starch affect absorption
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Which types of foods generally have low glycemic index values?
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Beans whole wheat fruits
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Which types of foods generally have low glycemic index values?
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Beans whole wheat fruits
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What is the value of eating lower glycemic index foods?
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Less dramatic fluctuations in blood glucose, insulin output
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What are two effects of its metabolism that increase the risk of obesity?
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diabetes, hypoglycemia, and lactose intolerance
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What is the AMDR for added sugars?
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< 25% of total kcals as added sugars
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How much fiber is recommended daily?
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At least 25 grams per day
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Nutritive sweeteners
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Contain 4 kcal energy per gram
Sucrose, fructose, honey, brown sugar Slow-absorbing sugar alcohols: *2-3 kcal/g |
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Sugar alcohols
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- mannitol, sorbitol, etc.
Do not promote *dental caries, half the kcals Too much causes *diarrhea |
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What is diabetes?
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Inability to regulate blood glucose levels between normal range of 80-120
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What are the risks of uncontrolled diabetes?
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Cause nerve damage, kidney damage, blindness, heart disease and can be fatal
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What are the major symptoms?
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Excessive urination, thirst, hunger
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Type I
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- the body cannot produce enough insulin
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Type II
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- body cells become resistant, or less responsive to insulin. Middle age and above, most prevalent type
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What is pre-diabetes?
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Insulin resistance, 126mg/dl
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What is the main risk factor of pre-diabetes, and how is it measured?
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abdominal fat, measured by waist circumference and waist to hip ratio
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What is metabolic syndrome, and what risks does it increase?
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Cental obesity, high blood pressure, high triglycerides, low HDL cholesterol, insulin resistance
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What are lifestyle and dietary strategies for type 2 diabetes that can help prevent and bring about remission?
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Balanced diet and regular excerise, achieveing and maintaining healthy body weight
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What is lactose intolerance? What are possible cause and strategies for management?
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Insufficient enzyme lactose to digest the lactose containing foods, find alternate sources of calcium, reduce lactose intake to <6g/d, fortified lactase products, fermented products
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Which foods contain dietary cholesterol?
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butter, egg yolks, whole milk, meats, and poultry
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Which contains the nitrogen?
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amine group
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Nitrogen balance
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(nitrogen consumption = nitrogen excretion) is the normal state of protein equilibrium
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positive nitrogen balance
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needed for peroids of growth, pregnancy, recovery from illness, or protein deficiency
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negative nitrogen balance
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results from starvation, comsumption of very-low-energy diets, severe illness, infections, serious burns, or injuries
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