Front Back
Nutrition
the study of the effect of food and nutrients on the health of living organisms
What are essential nutrients
nutrients that cannot be made in the body in a sufficient quantity, and therefore must be provided by a persons diet
What are the six classes of nutrients?
minerals, water, carbs, fats, proteins, vitamins
Minerals
inorganic simplest nutrient: single elements identity never changes
Water
inorganic next simplest made of two elements (H and O)
Carbohydrates
organic C,H,O
Fats
organic C,H,O
Proteins
organic C,H,O,N
Vitamins
organic C,H,O,N,S
What is the basic unit of energy?
kilocalories (kcal)
Kilocalories
the amount of heat energy required to raise one kilogram of water one degree celsius
Calories
the amount of energy needed to raise one gram of water one degree celcius
How do you measure energy?
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
Amount of kcals per 1 gram of CHO, protein, and fats
CHO: 4 Kcal/gram Protein: 4 Kcal/gram Fat: 9 Kcal/gram
How to calculate the % of kcals in a food or meal that come proteins, fats, and carbs
divide the amount of kcals by the total kcal count
How do we assess nutritional status?
by looking at anthropometric measurements, biochemical measurements, clinical trials, and dietary analysis's
Anthropometric Measurements
physical measurement of body broad picture of nutritional status; does not give specific information about nutrients EX: height&weight, skin-fold measurement, BMI
Biochemical Measuremnts
direct measurement: a nutrient EX: albumin - determination of protein status in blood functional measurement: a nutrient metabolite, enzymes
Clinical Tests
signs of nutrient deficiency: hair, nails, skin, tongue, etc. physical signs of dehydration and fluid retention
Dietary Analysis
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
Identify key components of the Nutrition Facts panel on a food label
identity net contents of package name and address of manufacturer/packer/distributor list of ingredients nutrition information
Daily Values (DV)
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
How can you evaluate your body weight?
by looking at your BMI
What is Body Mass Index (BMI) ?
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
What is the food guide pyramid?
a dietary guideline for healthy people - not a rigid prescription
What is the dietary reference intake?
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)
EAR
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
What is nutrient density?
...
AI
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
UL
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
RDAs
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…
Parts of the GI tract
1. Mouth 2. Esophagus 3. Stomach 4. Small Intestine 5. Large Intestine 6. Rectum
What happens in the mouth?
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
What happens in the esophagus?
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
What happens in the stomach?
where food is partially digested (chyme), churned, and stored until released into SI very little absorption Digests proteins
What happens in the small intestine?
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
What happens in the large intestine?
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
What are the parts/structure of the small intestine?
Duodenum Jejunum Ileum structure: folds, villi, microvilli
What are the part of the large intestine?
cecum colon rectum anal canal
Site/function of salivary amylase
site: mouth function: starch hydrolysis
Site/function of lingual lipase
site: mouth function: hydrolysis of fat
Site/function of gastrin
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
Site/function of hydrochloric acid
site: stomach function: to provide an optimum pH for the enzyme protease to work and also to kill pathogenic organisms in the stomach.
Site/function of stomach mucus
site: stomach function: to protect stomach cells from autodigestion by gastric juices (HCL)
Site/function of pepsin
site: stomach function: begins the breakdown of proteins into shorter polypeptide chains and single amino acids
Site/function of gastric lipase
site: stomach function: minor role - hydrolysis of short chain triglyceride (TG) to free fatty acid (FFA)
Duodenum
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
CCK
contracts gallbladder to release bile (~500 mL/day)
Bile
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
Jejunum
middle region of SI ~4 ft. 85% of water absorbed water soluble vitamins (thiamine, folate, ascorbate) amino acids
Ileum
last part of SI ~5 ft. water soluble vitamins and vitamin B12 bile acids
Pyloric Sphincter
the sphincter muscle of the pylorus that separates the stomach from the duodenum regulates flow of food into small intestine
Epiglottis
flap of tissue that protects the trachea while swallowing
Chyme
partially digested food in stomach
Micelle
A water-soluble spherical structure formed in the small intestine via emulsification.
Constipation
slow movement of fecal matter causes: ignoring normal urge, antacids, calcium/iron supplements treatment: plenty of dietary fiber/fluids, laxatives
Hemorrhoids
dilated or enlarged veins in the lower portion of the rectum or anus (internal or external)
Diverticulosis
small buldging pouches (diverticular) that buldge outward in the colon affects 50% of all americans aged 60-80 causes: low fiber diet
3 common monosaccharides
glucose, fructose, galactose
Glucose
blood sugar - dextrose (natural) not much in food comes from starch and surcrose
Fructose
fruit sugar - levulose converted to glucose in liver more lipogenic than glucose converted to lactic acid
Galactose
not much in nature converted to glucose in nature
3 common dissacharides
sucrose, lactose, maltose
Sucrose
glucose + fructose table sugar, fruits, veggies, grains
Maltose
glucose + glucose malt sugar big in alcohol
Lactose
glucose + galactose milk sugar
Oligosacchrides
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
Polysacchrides
many monosacchrides linked together depending on their linkage: starch: digestible dietary fiber: indigestible 2 forms of starches: amylose, amylopectin
Amylose
long straight chain wheat flour 20% of starch
Amylopectin
a long branched chain, making food thicker (e.g. cornstarch) 80% of starch
Glycogen
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
Simple carbohydrates
mono and disacchrides sugars referred to as empty calories
Complex carbohydrates
oligosaccharides: raffinose and starchyose polysaccharides: starch and glycogen dietary fiber
Major storage organ for glucose
liver
Effect of too much CHO intake
stored as fat
What happens with too little CHO intake?
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
Dietary Fiber
provides structure to plant cell walls - found in fruits, vegetables, legumes, whole grains different chemical bonding - not digested or absorbed insoluble and soluble fibers
Insoluble fiber
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
Soluble fibers
absorbs water and dissolves in it increases transit time - slow movement EX: apples, oat bran, vegetables reduces risk of diabetes
Functions of glucose in the human body
source of energy for the brain and the cells most abundant sugar molecule - monosaccharide
Glycemic Index
system of ranking foods according to how much they raise blood glucose relative to a reference food
Effect of high GI
rapidly digested or absorbed CHOs faster rise in blood glucose caused by refined CHO - e.g. potatoes
Effect of low GI
slowly digested or absorbed CHO slower rise in blood glucose caused by complex CHO or high soluble fiber - e.g. beans, oats, wheat
Glycemic Load
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
Effect of high GL
stimulates the release of insulin returns to hunger quicker muscle may become resistant to insulin insulin increases fat synthesis increased risk for CVD
Effect of muscle glycogen, plasma glucose, plasma free fatty acids, and muscle triglycerides on low, moderate, and high density exercise.
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
Lipids
a family of compounds that do not readily dissolve in water
Lipid Class
fatty acids tri(acyl)glycerides phospholipids seterols
Fatty Acids
simplest form of lipids a chain of C with H attached have methyl and acid group characterized by # of C and double bonds
Short chain fatty acid
2-4 carbons liquid in cold temp butyric acid EX: milk fat
Medium chain fatty acid
6-10 carbons solid in cold but liquid in room temp EX: coconut oil
Long chain fatty acid
12 or more carbons beef fat - solid at room temp plain origin - liquid at room temp
Saturated fatty acid (SFA)
all carbons are saturated with H usually solid at room temp mostly from animal sources except tropical oils
Unsaturated fatty acids (USFA)
have double bonds usually liquid at room temp mostly plant and fish sources more chemically active - spoil faster
Omega 3 FA
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
Omega 6 FA
essential FA first double bond at carbon 6 from the methyl end mostly in plants - corn, safflower oil linoleic acid - C18:2 n-6
Biological functions of Omega-3
EPA & DHA - produces eicosanoids dilates blood vessels, decreases blood clotting, reduces inflammatory response
Biological functions of Omega-6
most common in our diet produces eicosanoids constricts blood vessels, increases blood clotting, increases inflammatory response
Deficiency of fatty acids
dry, flaky, itchy skin liver abnormalities diarrhea poor wound healing infection growth retardation in infants impaired vision and hearing
Consequences of hydrogenation of FA
yields trans configuration
Commercial hydrogenation
increases stability by solidifying oils problem: acts more like SFA - increasing blood cholesterol
Monounsaturated FA
oleic acid - canola oil
Polyunsaturated fatty acid
linoleic acid - safflower, corn oil
Triglycerides
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
Phospholipids
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
Sterols
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
Cholesterol in food
high in brain, liver, and other organ meats (ex shrimp) high in egg yolks high in breast milk - important for infants
Fat intake and heart disease
#1 killer 60% more than cancer death men to women 2:1
Atherosclerosis
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
Blood cholesterol
elevated LDL increases risk elevated HDL decreases risk
High blood pressure
increases risk damages blood cells
Benefits to alcohol
some improve HDL and reduce CVD risk
Moderate drinking
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
Binge drinking
consumption of 5 or more alcoholic drinks on one occasion
Chemistry of alcohol
an organic compound that has one or more OH groups
Forms of alcohol
ethanol, methanol
Alcohol as organic solvent
dissolves fats and other lipophillic substances
Alcohol absorption
no digestion required both lipid and water soluble crosses blood brain and placental barriers 20% absorbed in stomach - 80% in SI

Access the best Study Guides, Lecture Notes and Practice Exams

Login

Join to view and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?