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Danny M.Pincivero

159 VITAMINS HISTORY OF VITAMINS • 3500 years ago, Arab and Egyptian physicians provided certain foods to help with star-gazing at night Hippocrates (≈ 400 B.C.E.) • Followed the practice of the Arab and Egyptian physicians • Prescribed beef liver to help see stars at night…..first documented discovery of vitamin A and treatment of “night blindness” James Lind • British physician • 1716-1794 • Discovered the health needs of vitamin C in British sailors • Scurvy….disease caused by vitamin C deficiency • Vitamin C necessary for collagen synthesis Signs and symptoms • Fatigue, anemia (low RBC count), hemorrhaging, teeth loosening, softening of bones KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 160 Christiaan Eijkman, Dutch scientist • Aug 11, 1858 – Nov 5, 1930 • Nobel Prize in Physiology or Medicine, 1929, "for his discovery of the antineuritic vitamin" (prevents neuritis – inflammation of nervous system) • Produced beriberi in chickens fed white rice…disease cured by feeding brown rice….due to the loss of a B-vitamin (thiamin) that occurs with rice polishing. • What is beriberi? • Beriberi…. “I can’t, I can’t” • Singhalese language (Sri Lanka) Signs and symptoms • Impairs glucose metabolism….nervous system problems (weakness, fatigue, depression). • Muscle wasting, uncoordinated movements Casimir Funk, Polish biochemist Feb 23, 1884 – Nov 20, 1967 Isolated an amine in rice…..nitrogen containing functional group. Discovered….providing an amine improved the health of thiamin deprived chickens. Referred to this “amine” as “vital” for life….therefore, we now have “vital” “amines”…or vitamins. WHAT ARE VITAMINS? • Organic molecules… carbon based • Required in small units (micrograms). • Individual units.. not chains like macronutrients • Do not contribute to the body’s energy needs ( in terms of kcals) • Classification: Fat-soluble (A,D,E,K) and water-soluble (B,C) • Enzymes supported by vitamins, enzymes required for energy KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 161 HOW ARE VITAMINS ABOSRBED? Water soluble vitamins: go straight from digestive system to CV system since they’re water-soluble, go straight into plasma of blood and can circulate through the body in that form Vitamin C 8 B-vitamins: B1– thiamin, B 2 riboflavin, B3– niacin, pantothenic acid, biotin, folat6, B12 B • Absorbed directly through intestinal cells and into CV system • Dissolves in blood so freely transported, kidneys function as blood cleaners • Susceptible to kidney filtration… beyond storage capacity • Vitamin B 12 is stored more than other water soluble vitamins • When you take more than needed, it just gets filtered out General rule: • Need daily ingestion of water-soluble vitamins (they’re not stored).. but not critical • Eating a large amt of raw egs impairs ability to absorb one of the B vitamins  deficiency • Example: vitamin C deficiency symptoms manifest after 20-40 days. • Toxicity: rare, but possible (B6) Fat soluble vitamins: • Absorbed with dietary lipids.. packaged into chylomicrons • Bioavailability = 40-90% of vitamins consumed • Efficiency decreases with greater caloric ingestion b/c vitamins are competing with other nutrients to get out of digestive system, some vitamins do better on an empty stomach.. but usually some fat intake is good with it Pathway? • Lacteal… lymphatic system.. CV system • Lipoproteins “broken up” • Chylomicron remnants taken up by liver.. stores vitamins Bears have very good storage capacity for vitamin A KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 162 B vitamins function largely as co-enzymes – become a component of other enzymes, activate enzymes, enable enzymes to do their job VITAMIN B1 - Thiamin • Part of the co-enzyme TPP (thiamin pyrophosphate) • Works with PDH (pyruvate dehydrogenase)  pyruvate to acetyl coA • B vitamins enable body to get energy eg ^ acetyl coA gets kreb cycle going to make ATP RDA: 1.1 mg/day (women), 1.2 mg/day (men) Deficiency • Caused by a reduction in food intake • Beriberi – (impairment of nervous system) chronic thiamin deficiency, chronic weakness, weight loss Food sources: whole grains, pork VITAMIN B2 - Riboflavin • Co-enzyme (FMN, FAD).. FADH2.. ETC.. ATP • B2 is necessary for reducing equivalent FAD to make ATP • Electron acceptor/transporter – krebs cycle • In order for cell to make 32 ATP, need electrons from cytoplasm inside mitochondrion, FAD required for glycolysis as well RDA: 1.1 mg/day (women), 1.3 mg/day (men) Deficiency • Ariboflavinosis, inflammation of membranes (mouth, eyes, gastrointestinal system, skin) • Accompanies other micronutrient deficiencies Food sources: milk and alternatives, whole grains, cereal products (fortified), white mushrooms VITAMIN B3 - Niacin • Nicotinic acid and nicotinamide….precursor for NAD and NADP (supports antioxidant functions of other vitamins) • Can be synthesized from tryptophan (EAA) RDA: 14 mg NE/day (women), 16 mg NE/day (men) NE = niacin equivalent KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 163 UL: 35 mg/day Deficiency • Pellegra (4 D’s, diarrhea, dermatitis, dementia, death) often afflicts those in developing countries; hard to get meat products to those countries Food sources: animal products (eggs, milk, meat, poultry, fish), whole grains Toxicity: • “Niacin flush” – supplement form (3-4x RDA), nicotinic acid form • Results in Blood vessel dilation, painful “tingling” sensation Pharmacological doses (3-4x RDA) • High doses to treat LDL cholesterol (must be monitored for side effects) BIOTIN • Co-enzyme, involved in the Kreb’s cycle • Part of pyruvate carboxylase (takes 3C pyruvate into 4C oxaloacetate which reacts with acetyl coA to form citric acid ) • Burning carbs increases fat metabolism which comes by way of this enzyme- burn carbs to make oxaloacetate which reacts with acetyl coA which comes from beta oxidation of fatty acids • Contributes to gluconeogensis, fatty acid synthesis AI = 30 micrograms/day Deficiency: caused by chronic consumption of raw egg whites - Avidin: protein in egg white that binds to biotin.. so it prevents body from absorbing biotin .. chronically high consumption will affect other biotin body contains in digestive system - To deactive avidin, cook le egg! Denatures proteins, makes biotin more bioavailable • Skin rash, hair loss, neurological symptoms Food sources: egg yolks, soybeans, fish, whole grains - Avidin in egg white affects biotin in egg yolks PANTOTHENIC ACID KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 164 • Part of co-enzyme A…..supports action of PDH to makes Acetyl CoA • Synthesis of lipids, neurotransmitters, hormones, hemoglobin AI = 5 mg/day Deficiency: fatigue, neurological symptoms Food sources: beef, poultry, whole grains, potatoes, tomatoes, broccoli Vitamin B 6 • Group of 6 compounds, operates as a co-enzyme Pyridoxal phosphate (active form) - PLP Pyridoxine provided in energy drinks Supports over 100 different enzymes • Protein metabolism • Blood cell synthesis • Carbohydrate metabolism • Neurotransmitter synthesis 1) Protein metabolism KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 165 • B 6art of aminotransferase (enzyme that transfers an amino group from one amino acid to another… formation of conditionally essential amino acids ) • Transamination: process of transferring one amino group from 1 amino acid to another • 11 non-essential amino acids • Without B ,6all amino acids become essential (won`t have ability to activate enzyme to make these conditionally essentials ) 2) Blood cell synthesis • Red and white blood cells • Assists with oxygen binding to hemoglobin Deficiency: Microcytic hypochromic anemia • Red blood cell is smaller than normal and lacks Hb (protein that binds oxygen and other molecules, without Hb, no O2 transport, no support for metabolism of cells) 3) Reduce risk of myocardial infarction (death of cardiac muscle tissue when blood supply has been disprupted) • High levels of homocysteine related to M.I. • PLP-dependent enzymes convert homocysteine to cysteine Homocysteine: homologue of cysteine • Causes proliferation of vascular smooth muscle (hardens blood vessels, makes them much less responsive to vasodilating) • Contributes to plaque formation • B6 enables enzymes to convert homocysteine to cysteine Homocystinuria: inherited disease, lack of enzyme metabolizing cysteine 4) Carbohydrate metabolism • Gluconeogenesis from amino acids • Facilitation of glycogen breakdown 5) Neurotransmitter synthesis • Serotonin, GABA, dopamine, NE (norepinephrine) KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 166 RDA • 1.3 mg/day (men and women) • Men (> 51 years) = 1.7 mg/day • Women (>51 years) = 1.5 mg/day • U.L. = 100 mg/day SOURCES: • Fortified ready to eat cereals • Meat, fish, poultry • Bananas, watermelon, potatoes DEFICIENCY • Rare……anemia, nervous system symptoms • General deficiency in micronutrients.. usually with low caloric intake TOXICITY: • 1000-2000 mg, leads to protein modification • Neurons affected….can lead to permanent nerve damage FOLATE • 3 parts….Glutamate, PABA, and pteridine • • Natural form: 3-11 glutamate molecules…only amino acid metabolized by brain neurons • Brain neurons rely preferentially on glucose but can also use glutamate or ketoacids which are generated from amino acid metabolism Small intestine: 1 glutamate remains…..becomes folic acid (most stable form used in supplements and fortification) Functions of folate: • Converted to a co-enzyme…..THFA (tetrahydrofolic acid) KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 167 • Accepts/donates 1-carbon groups (amino acid metabolism, DNA synthesis, cell division) • Important during periods of development , folate becomes important vitamin – ensures growing fetus continues to develop in the way that it should Recommendations • Empty stomach….100% absorption in supplement form….decreases with food intake. • Natural folate in food = 50-67% bioavailable • Most effective way is supplement on an empty stomach RDA: 400 micrograms DFE/day, DFE = dietary folate equivalents Pregnancy: 600 micrograns DFE / day due to basic function of folate of DNA synthesis and cell division Lactation: 500 micrograms DFE/day • Supplements recommended during childbearing age due to effect of ensuring proper cell division which occurs early on in pregnancy U.L. = 1000 mg/day, toxicity linked to B d12iciency (hives, altered RBC, and neurological symptoms) Folate sources • RDA = 400 micrograms • Dark green leafy vegetables, asparagus, broccoli, legumes • Fortified foods: cereal grains, bread, pasta, rice • Romaine lettuce (1.5 cups = 115 micrograms) – but only get 60% benefit of the folate Why the need to fortify foods? • Folate deficiency linked to birth defects (conception and early development) • Cooking easily destroys food sources of folate (steaming, stir-frying, microwaving) • Cooked carrots increases bioavailability of vitamin A.. its an exception Folate deficiency • Most prevalent vitamin deficiency…..why? 1. Inadequate intake (low intake of legumes, vegetables)….variety! 2. Inadequate absorption (not all bioavailable, we don’t access all of it) KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 168 3. Increased requirements (pregnancy, lactation) 4. B6 deficiency 5. Altered folate metabolism…..alcohol and drugs 6. Excessive excretion….diarrhea Folate deficiency (A) Heart disease….elevated homocysteine levels (B) Megaloblastic anemia: due to impaired DNA synthesis in developing RBC. (C) DNA synthesis impaired….RBC, WBC, and GI cells. (D) Neural tube defects • Incomplete closure of spinal canal (spina bifida) • Anencephaly: part or all of brain missing.. infant doesn’t survive Body can store folate for 1-4 months but people tend to still be deficient B 12obalamin, cobalt-containing compounds) • Key role in folate metabolism • B12eficiency….can lead to folate deficiency • Cobalt containing compounds • Water-soluble vitamin stored more than the other ones Function: helps to maintain myelin sheath Absorption • B12bsorbed in ileum and binds to a protein transporter • Taken to liver (primary storage site), bone marrow, and developing cells • GI disorders can reduce absorption, occurs as we age B 12A • 2.4 micrograms/day (men and women) KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 169 • Suggested to be higher in older adults • 30% will experience age-related atrophic gastritis (decrease in size of certain tissues, hypertrophy – growth of skeletal muscle, atrophy – muscle injury or disease where muscle fibers decrease in size, reuptake and breakdown of muscle protein) • If mucosal cells get smaller, microvilli get smaller, GI loses SA and thus absorptive capability decreases SOURCES • Fortified foods (cereals, soy-milk)….not normally in plant food. • Animal products (including diary) most abundant • Dietary sources approximately 50% bioavailable • Crab, clams, shrimp, beef all high sources (> 20% DV) Toxicity: None established, no U.L. , no toxicity risk Deficiency • Due to impaired absorption….may require monthly injections (B12 stored in liver) • Vegetarians at risk?....supplements or fortified cereals • Vegan mothers nursing…..recommended to take supplements • Pernicious anemia….abnormal development of red blood cells • Myelin sheath breakdown…..nerve degeneration….fatal if untreated. - B12 enables folate to work so without b12 can’t use folate which is necessary for mommies! B12 supplements recommended since it’s not found in plants. B12 bioavailability - Decrease with increased caloric ingestion - Target: approx. 1.5 mg/meal - Fish = 40% - Chicken = 60% - Eggs 9% KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 170 WHAT IS VITAMIN C? 2 biological active forms Ascorbit acid (reduced) dehydroascorbic acid (oxidized) 2 e- VITAMIN C FUNCTIONS: 1) Anti-oxidant • Stabilizes superoxide to peroxide • Oxidative damage – when oxygen molecule binds an electron – superoxide anion (produced during natural course of oxidation) disrupts integrity of other tissues.. DNA… cell membranes.. vitamin C neutralizes those effects 2) Collagen synthesis • Vitamin C involved in synthesis (part of connective tissue) • Tissue injury increases need for collagen • Inflammation when injured; part of inflammatory response is to make new collagen as an important component of new tissue o 3 stages of injury acute, subacute, chronic  Subacute – month or two, don’t seem to be getting better, collagen isn’t being synthesized at a fast enough rate or its getting broken down at the same rate its being made .. could be due to /affected by lack of vitamin C 3) Enhances non-heme iron absorption (plants); need Fe in blood. Less bioavailable but vitamin C enhances bioavailability of non-heme iron. When you cook with cast-iron, iron atoms on surface.. the heat energy breaks them off and they enter food sources. Healthiest type of cooking instrument due to extra iron you get from cooking process. 4) Synthesis of carnitine (made from lysine and methionine)….beta-oxidation (found on membranes of mitochondria inside cells, in order to get fatty acids from fat storage to get energy out, fatty acid has to bind to carnitine on membranes of mitochondria which activates the fatty acid and makes it unstable) 5) Supports immune function KIN 1F03 – Human Nutrition in Exercise and Health D.M. Pincivero, 2012 171 VITAMIN C DIETARY RECOMMENDATIONS: • Men = 90 mg/day • Women = 75 mg/day, 85 mg during pregnancy, 120 mg lactation (new other needs for mom and baby) • Tolerable upper intake = 2000 mg (very water soluble, very high dosages if not used by cells) • Sources (examples): citrus fruits, red/green peppers, broccoli, cauliflower, spinach If needs are not elevated and you take extra, it just gets filtered out by kidney. Toxicity • Megadose: Ingesting 10x RDA • 2000 mg, abdominal cramps, nausea, nosebleeds • Existing kidney disease……kidney stone development Hemochromatosis: metabolic disorder, excess iron deposits in body • Due to action of vitamin C enhancing iron absorption WHAT IS VITAMIN E? • Fat-soluble vitamin • 90% stored in adipose tissue, remaining in cell membranes • Exists as 2 sets of 4 different compounds (each) • Tocopherol and tocotrienol (alpha, beta, gamma, delta) • Alpha-tocopherol is the active form biologically • Need to digest and absorb dietary lipids to get vitamin E (up to 80% bi
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