NUTRITN 130: Midterm Exam
118 Cards in this Set
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Nutrition
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the study of the effect of food and nutrients on the health of living organisms
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What are essential nutrients
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nutrients that cannot be made in the body in a sufficient quantity, and therefore must be provided by a persons diet
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What are the six classes of nutrients?
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minerals, water, carbs, fats, proteins, vitamins
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Minerals
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inorganic
simplest nutrient: single elements
identity never changes
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Water
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inorganic
next simplest
made of two elements (H and O)
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Carbohydrates
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organic
C,H,O
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Fats
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organic
C,H,O
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Proteins
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organic
C,H,O,N
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Vitamins
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organic
C,H,O,N,S
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What is the basic unit of energy?
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kilocalories (kcal)
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Kilocalories
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the amount of heat energy required to raise one kilogram of water one degree celsius
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Calories
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the amount of energy needed to raise one gram of water one degree celcius
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How do you measure energy?
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Food + O2 ---> CO2 + Energy
* 40% ATP & 60% Heat*
Direct Calorimetry: measures the amount of heat released from foods using the bomb calorimeter (measures the energy stored in the chemical bonds in food)
Indirect Calorimetry: measures the amount of oxygen a person uses
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Amount of kcals per 1 gram of CHO, protein, and fats
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CHO: 4 Kcal/gram
Protein: 4 Kcal/gram
Fat: 9 Kcal/gram
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How to calculate the % of kcals in a food or meal that come proteins, fats, and carbs
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divide the amount of kcals by the total kcal count
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How do we assess nutritional status?
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by looking at anthropometric measurements, biochemical measurements, clinical trials, and dietary analysis's
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Anthropometric Measurements
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physical measurement of body
broad picture of nutritional status; does not give specific information about nutrients
EX: height&weight, skin-fold measurement, BMI
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Biochemical Measuremnts
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direct measurement: a nutrient
EX: albumin - determination of protein status in blood
functional measurement: a nutrient metabolite, enzymes
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Clinical Tests
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signs of nutrient deficiency: hair, nails, skin, tongue, etc.
physical signs of dehydration and fluid retention
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Dietary Analysis
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quality of information relies on peoples memories/honesty
methods: 24 hour recall,food records (3-7 days),food frequency questionnaires
evaluating dietary intake: dietary standards (RDA or AI), food pyramid, dietary guidelines for Americans
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Identify key components of the Nutrition Facts panel on a food label
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identity
net contents of package
name and address of manufacturer/packer/distributor
list of ingredients
nutrition information
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Daily Values (DV)
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compares the amount of one serving to the amount recommended for daily consumption (2,000 kcal)
DRIs not used on food labels because they are age and gender specific
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How can you evaluate your body weight?
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by looking at your BMI
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What is Body Mass Index (BMI) ?
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an index of a persons weight in relation to their height that correlates with total body fat content
weight (kg) / height (m)^2
weight (lb) / height (in)^2 X 750
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What is the food guide pyramid?
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a dietary guideline for healthy people - not a rigid prescription
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What is the dietary reference intake?
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a set of nutritional reference values that apply to healthy people
varies by age, gender, pregnancy, and lactation
has 4 different reference intakes (EAR, RDAs, AI, UL)
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EAR
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Estimated Average Requirement
average daily nutrient intake value that is estimated to meet the requirement of 50% of the population in a particular life stage or gender group
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What is nutrient density?
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...
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AI
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Adequate intake
a recommended average daily nutrient intake level based on observed/experimentally determined estimates of nutrient intake by a group of healthy people
used when EAR and RDA cannot be established
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UL
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tolerable upper intake level
the highest level of daily nutrient intake that is unlikely to pose health risks to almost all of the individuals in the general population
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RDAs
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Recommended Dietary Allowances
the average daily nutrient intake level that meets the nutrient requirements of 97-98% of healthy individuals in a particular life stage and gender group and uses the ear as a base
does not define individual requirements
set at a level at which most peopl…
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Parts of the GI tract
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1. Mouth
2. Esophagus
3. Stomach
4. Small Intestine
5. Large Intestine
6. Rectum
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What happens in the mouth?
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primary area for mechanical subdivision
moistens and lubricates food
tongue - mixing and maceration of food
has salivary and lingual serous gland
salivary amylase: starch hydrolysis
lingual lipase: fat hydrolysis
moistened lump of food is called Bolus
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What happens in the esophagus?
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tube to the stomach
has esophageal (cardiac) sphincter
peristaltic muscular contractions prevents food from coming back up (reverse peristalsis)
*Epiglottis: closes off the air passage and prevents choking
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What happens in the stomach?
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where food is partially digested (chyme), churned, and stored until released into SI
very little absorption
Digests proteins
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What happens in the small intestine?
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longest portion of GI tract; 10 ft. long - empty in 3-10 hrs.
mucosa cells renewed every 2-5 days
most digestion and absorption occur here
digests: everything but water
absorbs: everything
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What happens in the large intestine?
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where most water is absorbed and feces are formed; takes 18-24 hours; 5 ft. long in length
bacterial digestion of fibers
absorbs: vit./min, water
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What are the parts/structure of the small intestine?
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Duodenum
Jejunum
Ileum
structure: folds, villi, microvilli
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What are the part of the large intestine?
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cecum
colon
rectum
anal canal
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Site/function of salivary amylase
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site: mouth
function: starch hydrolysis
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Site/function of lingual lipase
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site: mouth
function: hydrolysis of fat
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Site/function of gastrin
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site: stomach
function: stimulates parietal cells/chief cells to secrete HCI and pepsinogen (inactive) ---> converted to an active pepsin by HCI
acid kills many pathogenic bacteria
helps partial digetion of protein
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Site/function of hydrochloric acid
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site: stomach
function: to provide an optimum pH for the enzyme protease to work and also to kill pathogenic organisms in the stomach.
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Site/function of stomach mucus
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site: stomach
function: to protect stomach cells from autodigestion by gastric juices (HCL)
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Site/function of pepsin
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site: stomach
function: begins the breakdown of proteins into shorter polypeptide chains and single amino acids
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Site/function of gastric lipase
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site: stomach
function: minor role - hydrolysis of short chain triglyceride (TG) to free fatty acid (FFA)
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Duodenum
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first part of SI - 10-12 inches
most digestion/absorption (95%) occurs here
secretes digestive enzymes, hormones, and mucus
dietary fat stimulates the release of CCK
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CCK
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contracts gallbladder to release bile (~500 mL/day)
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Bile
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not an enzyme - an emulsifier made in liver and stored in gallbladder
allows oil and water to mix and used as food additives
90% reabsorbed in the ilium
forms micelles
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Jejunum
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middle region of SI
~4 ft.
85% of water absorbed
water soluble vitamins (thiamine, folate, ascorbate)
amino acids
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Ileum
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last part of SI
~5 ft.
water soluble vitamins and vitamin B12
bile acids
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Pyloric Sphincter
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the sphincter muscle of the pylorus that separates the stomach from the duodenum
regulates flow of food into small intestine
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Epiglottis
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flap of tissue that protects the trachea while swallowing
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Chyme
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partially digested food in stomach
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Micelle
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A water-soluble spherical structure formed in the small intestine via emulsification.
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Constipation
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slow movement of fecal matter
causes: ignoring normal urge, antacids, calcium/iron supplements
treatment: plenty of dietary fiber/fluids, laxatives
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Hemorrhoids
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dilated or enlarged veins in the lower portion of the rectum or anus (internal or external)
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Diverticulosis
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small buldging pouches (diverticular) that buldge outward in the colon
affects 50% of all americans aged 60-80
causes: low fiber diet
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3 common monosaccharides
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glucose, fructose, galactose
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Glucose
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blood sugar - dextrose (natural)
not much in food
comes from starch and surcrose
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Fructose
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fruit sugar - levulose
converted to glucose in liver
more lipogenic than glucose
converted to lactic acid
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Galactose
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not much in nature
converted to glucose in nature
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3 common dissacharides
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sucrose, lactose, maltose
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Sucrose
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glucose + fructose
table sugar, fruits, veggies, grains
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Maltose
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glucose + glucose
malt sugar
big in alcohol
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Lactose
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glucose + galactose
milk sugar
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Oligosacchrides
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raffinose and starchyose
3-10 monosacchrides
not digested but metabolized by gut bacteria - gas and byproducts in the LI causing bloating, cramping, and discomfort
EX: beans, legumes, human milk
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Polysacchrides
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many monosacchrides linked together
depending on their linkage:
starch: digestible
dietary fiber: indigestible
2 forms of starches: amylose, amylopectin
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Amylose
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long straight chain
wheat flour
20% of starch
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Amylopectin
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a long branched chain, making food thicker (e.g. cornstarch)
80% of starch
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Glycogen
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a storage form of glucose in animals
stored mostly in liver and skeletal muscle
liver cells regulate blood glucose levels
highly branched chains of glucose
readily available
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Simple carbohydrates
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mono and disacchrides
sugars referred to as empty calories
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Complex carbohydrates
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oligosaccharides: raffinose and starchyose
polysaccharides: starch and glycogen
dietary fiber
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Major storage organ for glucose
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liver
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Effect of too much CHO intake
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stored as fat
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What happens with too little CHO intake?
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body cannot convert fat to sugar - makes more ketones (ketosis)
the body breaks down protein and converts to glucose to make energy (creating and filtering more waste)
liver and kidneys work harder
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Dietary Fiber
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provides structure to plant cell walls - found in fruits, vegetables, legumes, whole grains
different chemical bonding - not digested or absorbed
insoluble and soluble fibers
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Insoluble fiber
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do not dissolve in water - hold on to it
enlarges stools and softens it
decreases transit time - natures broom
EX: banana, whole grains, wheat bran, vegetables
too little intake: constipation, hemorrhoid, IBS, and diverticula
protects against colon cancer and helps weight
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Soluble fibers
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absorbs water and dissolves in it
increases transit time - slow movement
EX: apples, oat bran, vegetables
reduces risk of diabetes
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Functions of glucose in the human body
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source of energy for the brain and the cells
most abundant sugar molecule - monosaccharide
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Glycemic Index
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system of ranking foods according to how much they raise blood glucose relative to a reference food
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Effect of high GI
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rapidly digested or absorbed CHOs
faster rise in blood glucose
caused by refined CHO - e.g. potatoes
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Effect of low GI
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slowly digested or absorbed CHO
slower rise in blood glucose
caused by complex CHO or high soluble fiber - e.g. beans, oats, wheat
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Glycemic Load
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takes into account the amount of CHO in a common serving in addition to its glycemic index - a better reflection of food's effect on blood glucose
GL = (GI of CHO) (grams of CHO per serving) / 100
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Effect of high GL
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stimulates the release of insulin
returns to hunger quicker
muscle may become resistant to insulin
insulin increases fat synthesis
increased risk for CVD
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Effect of muscle glycogen, plasma glucose, plasma free fatty acids, and muscle triglycerides on low, moderate, and high density exercise.
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low: plasma FFA, muscle triglycerides, plasma glucose, muscle glycogen
med: muscle glycogen, plasma FFA, muscle triglycerides, plasma glucose
high: muscle glycogen, plasma FFA, plasma glucose, muscle triglycerides
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Lipids
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a family of compounds that do not readily dissolve in water
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Lipid Class
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fatty acids
tri(acyl)glycerides
phospholipids
seterols
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Fatty Acids
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simplest form of lipids
a chain of C with H attached
have methyl and acid group
characterized by # of C and double bonds
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Short chain fatty acid
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2-4 carbons
liquid in cold temp
butyric acid
EX: milk fat
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Medium chain fatty acid
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6-10 carbons
solid in cold but liquid in room temp
EX: coconut oil
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Long chain fatty acid
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12 or more carbons
beef fat - solid at room temp
plain origin - liquid at room temp
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Saturated fatty acid (SFA)
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all carbons are saturated with H
usually solid at room temp
mostly from animal sources except tropical oils
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Unsaturated fatty acids (USFA)
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have double bonds
usually liquid at room temp
mostly plant and fish sources
more chemically active - spoil faster
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Omega 3 FA
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essential FA
first double bond at carbon 3 from the methyl end
mostly in cold water fish (EPA, DHA), and in some plants (rapeseed oil, nuts seeds)
linolenic acid - C18:3 n-3
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Omega 6 FA
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essential FA
first double bond at carbon 6 from the methyl end
mostly in plants - corn, safflower oil
linoleic acid - C18:2 n-6
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Biological functions of Omega-3
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EPA & DHA - produces eicosanoids
dilates blood vessels, decreases blood clotting, reduces inflammatory response
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Biological functions of Omega-6
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most common in our diet
produces eicosanoids
constricts blood vessels, increases blood clotting, increases inflammatory response
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Deficiency of fatty acids
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dry, flaky, itchy skin
liver abnormalities
diarrhea
poor wound healing
infection
growth retardation in infants
impaired vision and hearing
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Consequences of hydrogenation of FA
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yields trans configuration
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Commercial hydrogenation
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increases stability by solidifying oils
problem: acts more like SFA - increasing blood cholesterol
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Monounsaturated FA
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oleic acid - canola oil
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Polyunsaturated fatty acid
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linoleic acid - safflower, corn oil
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Triglycerides
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most fats and oils in foods are in the form of TG (98-99%)
glycerol is the backbone of TG - glycerol + 3 fatty acids
synthesized in liver, adipose, and intestine
functions: energy source, satiety value, energy reserve, insulation and protection, micronutrient carrier, sensory qualities
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Phospholipids
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structure: diglyceride with FA attached at C1 and C2
ideal emulsifier -keeps fats suspended in water
function: structural element for cell membranes, temporary store of fatty acids, transports lipids
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Sterols
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structure: 4 aromatic hydrocarbon rings
present only in animal foods
most tissues can synthesize it
no dietary requirement
liver and intestinal cells can supply ~90% of endogenous cholesterol
major structural component of membranes
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Cholesterol in food
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high in brain, liver, and other organ meats (ex shrimp)
high in egg yolks
high in breast milk - important for infants
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Fat intake and heart disease
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#1 killer
60% more than cancer death
men to women 2:1
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Atherosclerosis
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build up of cholesterol and other materials forming plaque in blood vessel walls
restricting blood flow and increasing arterial blood pressure
inadequate blood supplies to the heart and brain
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Blood cholesterol
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elevated LDL increases risk
elevated HDL decreases risk
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High blood pressure
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increases risk
damages blood cells
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Benefits to alcohol
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some improve HDL and reduce CVD risk
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Moderate drinking
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12 oz beer
10 oz wine cooler
4-5 oz wine
1.5 oz of 80 proof distilled spirits
all contain ~15g of pure alcohol - 1 oz pure alcohol = 210 kcals
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Binge drinking
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consumption of 5 or more alcoholic drinks on one occasion
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Chemistry of alcohol
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an organic compound that has one or more OH groups
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Forms of alcohol
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ethanol, methanol
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Alcohol as organic solvent
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dissolves fats and other lipophillic substances
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Alcohol absorption
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no digestion required
both lipid and water soluble
crosses blood brain and placental barriers
20% absorbed in stomach - 80% in SI
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