11:709:255: Nutrition & Health - Study Guide
11:709:255: Nutrition & Health - Study Guide 11:709:255
Popular in Nutrition & Health
One Day of Notes
verified elite notetaker
Health Sport And Exercise Science
verified elite notetaker
verified elite notetaker
One Day of Notes
verified elite notetaker
One Day of Notes
verified elite notetaker
Popular in Nutrition and Food Sciences
This 30 page Study Guide was uploaded by Madison Notetaker on Thursday October 16, 2014. The Study Guide belongs to 11:709:255 at Drexel University taught by Sherman in Fall. Since its upload, it has received 86 views. For similar materials see Nutrition & Health in Nutrition and Food Sciences at Drexel University.
Reviews for 11:709:255: Nutrition & Health - Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/16/14
Glucose O2 fatty acid Amino acid Atpco2h2O Metabolism System of chemical reactions which release capture store amp use energy Covalent bonds brokerenergyATPheat Metabolic pathways The series of linked chem reactions that make up metabolism Catabolic Pathways breakdown Breakdown of the energy storing nutrients glucose amino acids and fatty acids Energy stores in the chem bonds of glucose amino acids and FA is transferred to oxidized coenzymes via catabolic pathways Start out with nutrients transfer the energy to the oxidized form of these coenzymes 3 major NAD FAD NADP All of these coenzymes are derived from vitamins As long as the body has tenough vitamin precursors then the body can make these coenzymes Can carry hydrogen ions and electrons The hydrogens are moving from the nutrients bond to the coenzymes and now the coenzymes are considered reduced NADHH FADH2 NADPHH In the process of transferring the hydrogens the nutrients are broken down C forms CO2 and water Anabolic Pathways synthesis Have reactions that result in the reverse process Reduced coenzymes transfer energy needed for anabolic pathways In order to synthesize the energy storing compounds the glucose amino acids FA and glycerol combine with the reduced coenzymes and the energy transfers from the reduced coenxymes to the nutrients to produce energy storing compounds glycogen proteins and TG Coenzymes give up their hydrogens so can do catabolic energy transfer once again ATP Made up of 3 units 5 carbon sugar ribose ribose bonded to the base Adenine when Adenine and ribose are bound together it forms Adenosine the a of atp attached to the Adenosine molecule are 3 phosphate groups tri phosphate the energy is stored in the chemical bonds that link the phosphate groups to each other when energy is needed to fuel a chem reaction in the body water comes in and atp is broken down one of the phosphate groups is thrown off so whats left is ADP adenosine diphosphate and one molecule of inorganic phosphate this releases energy because that broken bond is high energy breaking it releases that energy can be used to fuel a chem reaction in body the phosphate can reatacht to ADP if there is enough energy in the cell to recreate ATP ATP synthesis molecule of water is lost in this process we don39t have ability to store much energy in form of ATP We make it as we need it Rather we store it as glycogen protein etc The Basic Cell In cytoplasm 15 set of reactions occurs glycolysis start out with glucose and end up with pyruvate the resulting products of glycolysis move to mitochondria mitochondria citric acid cycle electron transport chain oxidated phosphorylation ADFATP Cytoplasm 6C molecule of glucose first step of glycolysis requires some ATP to get started generate ATP the reduced form of coenzymes that can go into mitochondira for electron transport C atoms glucose molecules split into 2 3C molecules called pyruvate Aerobic metabolism Pyruvate molecules move into mitochondria and in presence of oxygen pyruvate is broken down loses a C and forms a molecule of CO2 the remaining 2 carbons combine with CoA coenzyme A AcetylCoA is produced which goes into the citric acid cycle Anaerobic metabolism Pyruvate molecules are comverted into another 3C molecule called lactate Lactate is transported from cytoplasm to liver where it enters another metabolic pathway called the Cori cycle which recycles the carbons in the lactate to form more glucose Citric Acid Cycle AKA TCNKrebs Cycle Series of chem reactions that are cyclical There are several intermediate products that contain C atoms in the cycle Pyruvate comes from cytoplasm if theres enough Oxygen moves into mitochondria and coverted into AcetylCoA 2 carbons bound to coenzyme A For acetylcoa to enter cycle it needs to lose CoA 4 carbon molecule combines with these 2 carbons the 4C molecule is Oxaloacetate this combo forms a 6C molecule called citrate chem energy in this is released through a series of reactions that forms intermediate products the energy is transferred to the oxidized forms of coenzymes enter into electron transport chain the 6C molecule Citrate combines with O forming Co2 the oxidized enzyme NAD picks up 2 hydrogens NADHH goes to electron transport chain now we have 5C intermediate product can be used for synthesis of certain amino acids or it can contine releasing more carbons to form CO2 produces 4C intermediate product that can also be used to fomr certain amino acids or there can be a loss of 2 hydrogens picked up by FADgtFADH2gtelectron transport chainATP lose more H end product of citric acid cycle is Oxaloacetate Mitochondria NADHH and FADH2 pass along a series of protein complexes called the electron transport chain The reduced coenzymes enter into the protein complexes The electrons and hydrogens are released from the reduced coenzyme regerneating the oxidized form of the coenzyme The energy released used to move the electrons along and to pump the hydorgens from the mitochondrial matrix into the inner membrane space A the concentration of H ions ncreases in inner membrane space creates a force allowing H to move through a H channel This activates the enzyme responsible for the synthesis of ATP Enzyme ATP synthase catalyzes reaction that enables ADP to bond to inorganic phosphate to generate ATp ATP synthesisized by transferring energy creating a force that catalyzes an enzyme At completion of chain water is formed More metabolic Pathways proteolysis The process by which proteins are broken down to produce amino acids in the body glycogenolysis The breakdown of stored glycogen Requires a number of steps bc glycogen molecules are huge Glycolosis Break down of fat Amino acids Some can be used to generate pyruvate Some cannot be converted to pyruvate rather AcetylCoA Some are converted to oxaloacetate Triglycerides FA long molecules lose their carbons 1 at a time through a process by beta oxidation The net result is FA being broken down into either AcetyCoA or brokendown completely into CO2 Glycerol Easily converted into pyruvate Enters metabolism as pyruvate Ketogenesis Occurs during starvation or extremely low carb diet Body breaks down TG to release the FA and glycerol The FA are oxidized into acetylcoa Some of the amino acids also form acetalcoa These are referred to as ketogenic amino acids In order for acetylcoa to eneter citric acid cycle it must combine with oxaloacetate oxaloacetate is diverted from citric acid ccle and used for glucose synthesis via gluconeogenesis This happens because the cell does not have enough glucose in these conditions So now there is not enough oxaloacetate to combine with acetylcoa So acetyal coa cant enter citric acid cycle Instead enters ketogenesis Produces keytones 3amp4C molecules you can actually smell them on the breath of someone who is fasting diabetic etc Keytones are released into the blood where they are taken up by some tissues and metabolized for energy Toxic situation Alcohol Has 7kcalg Components of a Nutrition Assessment Background histories Med history including current disease past surgeries and unintentional weight loss Medications history some meds can interfere w absorption of nutrients food may influence abil of med etc Social history marital status cooking facilities Family history Economic status Education attainment this is time consuming Most physicians wont take this kind of time so its important to have dieticians in all types of settings so they can get this info Nutrition Parameters Anthropometric assessment height weight skinfold thickness very rough estimate of body fat arm muscle circumference and other parameters Biochemical laboratory assessment of blood and urine enzyme activities concentrations of nutrients or their byproducts Blood calcium levels are hormonally regulated Deposited from bone into blood under direction of hormones that resoind to blood calcium levels w goal of maintinaing a very constant level of blood calcium So has nothing to do w dietary calcium intake Clinical assessment physical examination general appearance of skin eyes and tongue rapid hair loss sense of touch ability to walk Diet history usual intake or record of previous days meals BMI weight in Kgheight in meters squared Bioelectrical impedence of body fat based on conduction of electricity Types of Diet Evaluations Food record Weight food record USED IN CLINICAL SITCH OR UN RESEARCH STUDY People actually weigh the food 3 day food record 7 day food record 24 hour recall some people better than others interviews food frequency questionnares great flexibility in terms of how they are conducted used most effectively to look for a particular trend if you are studying fat for ex identify high fat foods and see how often a person eats it Diet history The most vague Ask person to go back in time and tell you how they ate as a child a teen etc tell you if their diet has changed These are suggestive of adequacy NOT diagnostic of deficiency Water Soluble Vitamins Share some similar properties Vitamins in foods Typically bound to proteins that must be cleaved prior to absorption Many vitamins are not bioavailable bc they are bound to proteins The bonds need to be broken in order for them to become bioavailable and to be absorbed Easily destroyed during cooking Like if you chop and boil spinach all the vitamins are now in the water not the spinach Digestions Most digested in mostly the small intestine Absorption Absorbed mostly in small intestine but also in stomach Absorbed via simple diffusion when intake is high vitamin naturally moves from high concentration of lumen and naturally diffuse to lower concentration in enterocyte and active transport when intake is low carrier and ATP Bioavailability is influenced by many factors The protein bond may be resistant to cleavage the needed enzyme to do that could be low Circulation Transported via blood to liver Func ons Many coenzyme and other roles especially in energy metabolism Toxicity Effects Minimal although some exist Thiamin Riboflavin Niacin Involved in chemical reactions that release energy from CHO fat an protein producing ATP Thiamin Coenzyme TTP thiamin pyrophosphate Func ons 1 TTp acts as a coenzyme in reactions that remove a molecule of CO2 Decarboxylation reactions In order for the enzyme to be successful in removing this carboxyl group the coenzyme TTP must be present Pyruvate acetyl CoA Citric acid cycle 2 synthesis of DNA amp RNA 3 synthesis of NADPHH for TG synthesis 4 nerve function involved in synthesis of neurons Thiamin Deficiency Beri Beri I can39t I can t you feel unable to carry out aspects of daily living lack of neuromuscular control muscles nerves GI track affected Edema wet form the accumulation of fluid in interstitial spaces swelling Cerebral beri beri Alcoholism also called Wernike Korakoff syndrome Confusion memory problems Reason this deficiency affects nervous system CNS requires glucose wo thiamin glucose cannot be used Develops very quickly 10 days wo source of thiamin No such thing as thiamin stores Excess is always secreted through the urine Food sources look in textbook most grains are fortified w these vitamins Riboflavin Found in milk destroyed by light reason why mile contaniners are usually opaque Coenzyme FMN amp FAD Func ons 1 energy metabolism oxidationreduction reactions re dox 2 fat synthesis amp lipolysis 3 activates vitamin A folic acid pyridoxine vitamin K 4 needed for conversion of tryptophan to niacin tryptophan is an essential amino acid it takes a lot to make a little niacin rare to see these deficiencies in the US Usually due to some absorption disorders etc Our staple foods tend to be fortified with these major vitamins Prevalent in other places in the world Riboflavin Deficiency Aka ariboflavinosis Inflammation of tongue and mouth cracking corners of mouth eye disorders confusion Takes about 2 months for symptoms to develop Can be reversed when riboflavin is provided into diet Niacin Co enzyme NAD amp NADP Func ons 1 Niacin coenzymes Redox reactions in energy metabolism gt200 enzymes 2 coenzymes synthesis of hormones cholesterol amp DNA 3 coenzymes Repair of DNA Niacin can be synthesized in the body 60mg tryptophan 1 mg niacin costly process in body because then that tryptophan is not available for incorporation in protein can bring down cholesterol levels large doses of niacin can make you flush this mechanism is unknown Niacin Deficiency Aka Pellagra after about 50 days of no niacin Italian word that means rough skin Symptoms the 4 D39s Dermatitis rough skin esp in sun exposed areas of the body Diarrhea Dementia Death still a problem in poor countries esp in countries where dietary staple is corn in corn niacin is tightly bound by a protein that is not easily broken down by digestion Corn is often treated to facilitate this breakdown We see this in poorer countries because even if corn is a staple richer diets typ have more protein the tryptophan can be used from the protein to create niacin Dietary Needs Adequacy RDA is calculated based on kcal consumption The more kcal you consume the more of these vitamins you need because they all are involved in this energy metabolism Excesses of Thiamin Riboflavin and Niacin All secreted none stored Generally not toxic 1 exception is flushing due to Niacin in very high doses Thiamin influenced by alcoholism When alc consumption is excessive the GI track is damaged and influences the absorption of Thiamin Alc has no niacin Biotin Water soluble Uses Assists in carboxylation reactions CO2 Energy production amp fatty acid synthesis Only 23 essential FA but lots of others that can be synthesized from essential if there is enough or from biotin There are small amts absorbed in large intestine by micorbiota If taking antibiotics for a long time you can develop slight vitamin deficiencies if that vitamin is also synthesized by microbiota So if you re on antibiotics its helpful to take vitamin supplements the only reported case of deficiency in humans reported by someone who decided to consume only raw egg whites In raw egg whites there is a protein called avidim that binds biotin and makes it unavail to be absorbed cooked egg whites denatures the avidim though Pantothenic Acid Water soluble Very difficult to dvlp a deficiency of Pantos means everywhere component of Coenzyme A CoA needed in conversion of pyruvate to AcetylCoA Carried 2 C units The Acetyl in AcetylCoA is these 2 C units Energy production amp synthesis of FA hormones neurotransmitters Pyridoxine Aka Vitamin B6 pyridoxal the amine form called pyridoxamine The coenzyme is PLP pyrodoxal pyrophosphate Func ons 1 Transanimation reactions amp synthesis of NEAA the reactions where there is a transfer of the amino group NH2 from one carbon skeleton to another process by which we can synthesize the non essential amino acids in the body 2 Neurotransmitter synthesis depression confusion headache PMS type symptoms that can all be alleviates by pyridoxine supplementation too high levels can lead to nightmares and other symptoms keep supplement around RDA level 3 Glycogen breakdown and Gluconeogenesis requirement varies with protein intake 15 mgd a common supplement level is around 36 mgd which is assoc w neg side effects Pyridoxine Deficiency Microcytic hypochromic anemia anemia means there is something that weakens the blood makes it less capable many types of anemia this type the red blood cells are abnormally small they have a low amt of color they are very pale The paleness is related to the amt of hemoglobin in the cells pyrodoxin is required for the synthesis of the hem in hemoglobin also needed in helping the oxygen in bonding to the hemoglobin nerve damage individs at risk for deficiency oral contraceptive users if on it for a year or longer take a supplement w pyridoxine in it elderly prob related to changes in GI track that affects absoption alcoholics Toxic in megadoses gt200 mgd Know the food sources Folic Acid Aka folate folacin THFA is the coenzyme form Func on Coenzyme in reactions involving transfer of methyl groups CH3 Synthesis of amino acids Formation of heme of hemoglobin Synthesis of DNA needed to synthesize purine amp pyrimidine portions of DNA molecule Conversion of amino acid Homocysteine to amino acid methionine Folic Acid Deficiency Megaloblastic anemia Characterized by abnormally large red blood cells Red blood cells formed in bone marrow from precursor cells called stem cells If nutrition is adequate as cells mature they divide into normal red blood cells Flatter in the center which gives them greater flexibility to fold in and fit into capillaries This structure is called biconcave structure Mature red blood cells no longer have oxygen or organelles to make room for maximum hemoglobin Mycrocytic anemic cells divide into very small cells because they never get the message to stop dividing because they have enough hemoglobin before they are released Megaloblastic cells are unable to divide Normal maturation involves division and getting progressively smaller but these cant divide cant mature and not nearly as good at transporting oxygen and carbon dioxide Folic Acid RDA For adults 400 ug micrograms day UL upper limit 1000 pgday really high amounts can mask any B12 deficiency this has neurological effects even though the blood cells look normal Folic acid Foliage Dark leaved spinach kale chard Average Consumption of Folic Acid 180250 pgday a lot of people don t like foliage type foods so a lot of staple foods are now fortified in the US Who is at risk for deficiency Pregnant and young women Elderly Alcoholics Drugs some prescriptions can interfere w absorption of folic acid Folic Acid and Neural Tube Defects Insufficient folate intake genetic predisposition risk Neural tube does not close properly exposing neural tissue 15 3 weeks of pregnancy crucial before women skip their first period Vitamin B12 Aka Cobalamin Vitamin b12 can be stored in the body Non vegetarians have about a 7 year supply stored in the body vegetarians esp vegans have much lower reserves Need intrinsic factor to absorb adequate amount of B12 Intrinsic factor made in parietal cells of stomach and carries B12 thoughout GI track until it is absorbed Pernicious anemia stop manufacturing or manufactures defective intrinsic factor Func ons Essential or DNA synthesis Dvlp of Myelin sheath on nerve fibers Deficiency Leads to pernicious anemia All B12 is synthesized by microorganisms in the large intestine So meat eaters has b12 synthesized by microorganisms of a cow39s gut and incorp into beef for ex There is n o b12 in plant foods Vegans get very little b12 At most risk for deficiency Vegans Elderly Babies of vegans mother39s milk as too little b12 energy metabolism nutritional assessment vitamins all on the 3 exam Pyridoxine B12 Folic Acid Thought to be homocysteine lowering agents Homocysteine is a derivative of an amino acid found in the body Lower levels of this are associated with a decreased risk of heart disease When these leves are very high that this leads to a deposition of cholesterol from LDL in the arteries When adequate levels of B12PLP folic acid the homocysteine is converted into Methionine If one of these vitamins is limiting this reaction doesn t occur and the HC builds up in high levels and thought to contribute to increases levels of cholesterol build up and plaque in the arteries Vitamin C Aka ascorbic acid Easily destroyed by heat 02 high pH Func ons Antioxidant Accepts and donates electrons and Ht to other substances In redox reactions involving enzymes needing Cu or Fe vitamin C recharges mineral The enzyme needs the mineral in a specific state and so Vit C allows the mineral to repeatedly serve the same function 1 collagen formation Cu containing enzyme vitamin c is needed in conjunction with the process of changing 2 different amino acids to a unique form These AA are lysine and proline into hydroxyproline and hydroxylysine This requires a copper containing enzyme Collagen is a molecule that is important in connective tissue in the body Collagen is a 3 stranded helix shaped molecule These 3 strands are held together by corsslinks of hydroxyl groups Vitamin c is needed to recharge the copper in the enzyme that creates these hydroxyl groups and form the hyfroxylysine and hydroxyproline that attach to the carboxyl groups creating a very strong collagen molecule Without vitamin c you just have very disorganized strands of protein that are very weak and not really linkedto gether Collagen unable to crossline resulting in prro wound healing and ruptured capillaries 2 carnitine synthesis carnitine is a molecule important in fatty acid sedation In order to use fats for energy they need to be oxidized and carnitine is one of the molecules involved in this process 3 involved in converting the amino acid phenylalanine into tyrosine 4 Involved in neurotransmitter synthesis 5 Some hormone synthesis 6 Free radical scavenger Free radicals are formed continuously in the body A free radical is a molecule that is missing an electron in its outershell This makes it very unstable and they will go around look for other molecules and steal their electrons making the other molecule a free radical It creates this long chain reaction of free radcals in the body The reduced form of vitamin c has these electrons in its outsherll that can be donated to a free radical By donating an electron it makes the reactive free radical into an unreactive atom FR may be an underlying process in heart disease cancer and cataracts Vitamin c rich diets could help to protect against these things Helps prevent LDL cholesterol from being attacked and becoming a reative fr smoking and cancer is thought to be involving ree radical damage 7 improves absorption of Fe iron has poor bioavailability We absorb about 10 of the iron we eat in our diet Some dietary factors can improve the absorption Vitamin C Deficiency Scurvy Connective tissue collagen is affective Pinpoint hemorrhages Bleeding gumsteeth Unhealed wounds Bone pain 2040 days without vitamin C in diet RDA 75 mg women 90 mg men 35 mg Cigarette smokers UL2g Excreted in urine and high acid urine can help to precipitate calcium in the form of kidney stones General characteristics of Fat Soluble Vitamins Food sources Typically found in fatty portions of foods Except for Vit D easily destroyed by heat andor light Digestion Very little needed Absorption Occurs mostly in the small intestine Requires incorporation into micelles formed during fat digestion and the actions of bile Once transported into the intestinal cell vitamins are packaged with other lipids into chylomicrons which have a coating of protein molecules which makes them slightly soluble in water Circulation Away from the GI track Via lymph Func ons Gene regulation and carious other functions Regulate the expression of genes and determine which sections of DNA are transcribed and translated so specific proteins can be formed Toxicity Except for vitamin K toxicities are dangerous and sometimes fatal Vitamin A 2 forms retinoids preformed vitamin A animals carotenoids provitamin A beta carotene plants these are actually pigments in plant foods there are other forms of carotenoids but beta carotene is the most active and significant in terms of human health RAE retinol activity equivalent 1 RAE I pg retinol 12 ug Bcarotene Func ons 1 vision rhodopsin amp corneal health in the retina we have nerve tissue and then rod cells and cone cells Rod cells allow us to see in dim light and cone cells allow us to see in bright light In the rod cells is rhodopsin An Opsin portion which is a protein and that is bound to a very specific form of vitamin A called cisRetinal Light hits the rhosopsin which hits the cisretinal converting it to trans retinal Then the molecule splits The opsin goes one way and the transretinal causes a neural signal to be sent to the brain enabling a visual perception in dimly lit circumstances The trans retinal is then converted to part cis retina to allow this cycle to continue It also is converted into Retinoic acid This is another form of vitamin A that cannot join with Opsin to form Rhodpsin So every time this cycle occurs we are losing some of our usable vitamin A vitamin a deficiency night blindness cant see in the dark Early sign of vit a deficiency Leading cause of blindness world wide is vitamin a deficiency 2 cell differentiation regulation of gene expression all cells start out as immature undifferentiated cells Vitamin a comes in into this immature cell interacts with the DNA in the nucleus and up reguates specific genes that leads to synthesis of specific proteins causing the differentiation of the cell The cell will become a mature epithelial cell 3 growth and reproduction 4 immune function 5 cancer Mixed reports with regards to the possible protective features of vit a against the dvlpmt ofcancer 6 bone formation health benefits of carotenoids it serves as an antioxidant Vitamin A Deficiency Those at risk lndivids who don t eat fruitveg Poor Alcoholics Elderly Mild symptom Night blindness cant see in dark light Reversible Severe may not be reversible xeropthalmia affect cornea thin white cloudy tissue over eye bitot s spots affect cornea foamy looking areas on surface hyperkeratosis dry scaly lesions on skin infections can be cause of death measles for example vit a deficiency compromises the immune system so much that a relatively non dangerous infection can easily become lethal secondary to diseases of GI track liver pancreas alcoholism RDA stored in lever 700 RAE women 900 RAE men preformed vitamin a the animal form can be toxic and lead to a syndrome called hypervitaminosis A bone fracture loss of hair dermatitis fetal malformations UL 3000 RAE Hypercarotemia not dangerous You turn orange from eating carrots from excess beta carotene Vitamin K Phylloquinone plants Menaquinone animals intestinal bacterial fish oil meat Our microbiota absorb vitamin k in our bodies Antibiotics can result in vitamin k deficiency Func ons 1 blood clotting 2 carboxylation of glutamic acid in proteins of bone osteocalcin and teeth Vitamin K and Blood Clotting Blood clot formation very well regulated Involve a cascade of chemical reactions Inappropriate blood clot formation can be prevented by the presence of inactive clotting factors Inactive compounds need to be converted to their active forms Vitamin k an calcium in different activation reactions are involved in activating these inactive clotting factors in the body The series of reactions is triggered by some type of wound involving bleeding this involves a number of different clotting factors Once the clotting factors are active they are needed to convert another protein molecule This molecule Prothrombin is activated to form Thrombin In inactive states there is very little thrombin present Once thrombin is formed thrombin catalyzes the conversion of a precursor molecule called fibriniogen an inactive form of a water soluble protein into Fibrin Fibrin is active and water insoluble protein Water insoluble means its not soluble in the blood It forms this netting that traps the blood cells so they cant continue to leak out of the body This is the blood clot Vitamin K and carboxylation of glutamic acid in proteins of bone osteocalcin and teeth An important step in the synthesis of proteins involved in bone structure In order to build strong bones we need the right protein matrix for the minerals to be deposited in the bone Osteocalcin AI 90 ug women 120 ug men No UL nontoxic Vitamin K deficiency Excessive bleeding Rather rare because we have intestinal microbiotal synthesis of vit K Conditions in which we most often see vit K deficiencies Lipid malabsorption Long term use of antibiotics Vitamin E Aka alpha tocopherol Func ons Antioxidant Stops free radical chain reactions 1 Protects cell membranes against free radical compound damage free radicals damage oxidize fatty acids in the phospholipid bilayer vitamin e reduced free radicals stabilizing the so that they do not damage the cell membrane 2 cancer protects DNA thought that DNA is mutated by free radicals 3 cataracts protects against free radical damage that can lead to cataract formation 4 heart disease protects against free radical damage to fats in arteries and arteries themselves vitamin e from foods not supplements is protective RDA 15mg PUFA As the diet increses in PUFA content then body tissues incrs their levels UL 1000 mg The main problem with toxicity is that it can interfere with vitamin k levels in the body by inhibiting vitamin k activity in the body Vitamin E deficiency Hemolytic anemia An anemia brought about by the red blood cells being broken down abnormally Fat malabsorption Preterm infants Born with very low vit e stores Vitamin D Ergocalciferol plants Cholecalciferol animals We think of it as a hormone Synthesis in skin UV light It is a vitamin because there are a lot of people who cannot expose their skin to light Precursor is 7 dehydrocholesterol This is manufactured in the skin and it is exposed to UV light and it is converted into Previtamin D3 aka Precalciferol Previtamin D3 is converted to vitamin D3 aka cholecalciferol Cholecalciferol travels from the skin to the liver via the blood Activation liver and kidneys In order to function vit d must be activated The vit d that is synthesized by the skin is not very active Very well regulated 2 step process first in the liver then the kidney Cholecalciferol that has been transported to the liver from the skin must be activated The signal for this activation originated from the parathyroid glands These are 4 glands on the thyroid glands in the neck region They can sense blood calcium levels the active form of it D is needed to maintain normal blood Ca levels when these glands detect blood Ca levels that are too low they secrete parathyroid hormone PTH into the blood The PTH travels from parathyroid glands to he kidney via the blood The liver converts cholecalciferol to 25 OHD3 and transports it to kidney The kidneys convert it to 125OH2D3 aka calcitriol in response to the PTH Calcitriol is the hormone form or most active form of vitamin D We only synthesize what we need because if we have excess 125 Its going to continue on its mission increasing blood Ca levels and once that39s where we want it we don t want high blood Ca levels Func ons 1 calcium homeostasis 3 major target organs for the action of 125 Intestine Increased calcium absorption in the small intestine Kidneys Decreased calcium excretion by the kidneys Bones Increased calcium resorption in bones Ca relesased from bone to blood 2 cell differentiation bone amp intestinal cells there are vitamin d responsive genes 3 cancer May be protective against specific cancers esp prostate cancer Vitamin D Deficiency 1 osteomalacia inadequate mineralization of bone poor bone formation the mineral just isn t there leads bones to become soft In adults takes a long time to develop 2 osteoporosis demineralization of bone porous bones due to the loss of mineral from the bone more prevalent in adults esp in postmenopausal women because estrogen is protective against this 3 rickets occurs in children bones are so soft because there is so little mineral layed down in the bone matrix that when a child begins to stand their legs bow out poor diet and very little exposure to sunlight Vitamin D RDA 15 mg adults to 50 years 15 mg 5170 years 20 mg 71 years hypercalcemia vit d toxicity Ca levels in the blood are too high UL1OO ug from supplements At risk for Vit D Deficiency Breast fed infants Prob just not right Older adults Limited sun exposure Dark skin Fat malabsorption obese
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'