Transcript Vitamin C
NS 315 Unit 7: Water Soluble Vitamins Jeanette Andrade MS,RD,LDN,CDE Kaplan University Objectives • What are we going to learn about tonight? – – – – – Vitamin C Vitamin B1 Riboflavin Niacin Pantothenic Acid – – – – Biotin Folate Vitamin B12 Vitamin B6 Vitamin C • Also known as ascorbic acid • We have to obtain vitamin C through the diet • RDAs: – Males 19-70 years old 90 mg/day – Females 19-70 years old 75 mg/day – Smokers males 19+ 125 mg/day – Smokers females 19+ 110 mg/day • What foods contain Vitamin C? Functions of Vitamin C • Required for the synthesis of collagen • Required for the synthesis of neurotransmitter; norepinephrine • Required for synthesis of carnitine (fat oxidation) • Effective antioxidant Deficiency of Vitamin C • The more severe deficiency- scurvy occurs with lack of vitamin C in the diet • Scurvy: – Rare in United States, but can occur in malnourished and alcoholics – Bruising, bleeding gums and dental problems, anemia and dry hair http://www.merck.com/mmhe/sec12/ch154/ch154i.html Toxicity of Vitamin C • Up to 2 gm of vitamin C per day causes no adverse effects • Most common problems are abdominal pain and osmotic diarrhea (due to unabsorbed vitamin C) • At risk populations: Renal disease patients, hemochromatosis, thalassemia and sideroblastic anemia patients Vitamin B1 • Also known as Thiamin or Aneurine • Phosphorylated forms: Thiamin monophosphate (TMP), Thiamin triphosphate (TTP), and Thiamin pyrophosphate (TPP) • RDAs for Thiamin: – Males 19-70 years old 1.2 mg/day – Females 19-70 years old 1.1 mg/day • What foods contain Thiamin? Functions of Thiamin • Coenzyme function as TPP • Assists in pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and branched-chain ketoacid dehydrogenase • Coenzyme needed in Pentose Phosphate Pathway, an alternate for glucose oxidation Thiamin Some Thiamin Containing Enzymes http://pubs.niaaa.nih.gov/publications/arh27-2/IMAGES/Page138.gif Deficiency of Thiamin • Primary deficiency: people consuming white rice or highly refined carbohydrates in developing countries (Beriberi) and alcoholics (Wernicke- Korsakoff Syndrome) • Secondary deficiency: Increased demand, impaired absorption, impaired metabolism • 3 common Beriberis: – Dry – Wet – Infantile http://www.merck.com/mmpe/sec01/ch004/ch004f.html Beriberi • Dry: – Peripheral neurologic deficits – Effect mainly lower extremities and with continued deficiency will effect the arms • Wet (cardiovascular): – Vasodilation, tachycardia and lactic acidosis – Heart failure develops • Infantile – Occurs in infants (3-4 weeks old), breastfed by thiamin deficient mothers – Heart failure- may occur suddenly http://www.merck.com/mmpe/sec01/ch004/ch004f.html Riboflavin • 2 coenzyme derivatives: – Flavin mononucleotide (FMN) – Flavin adenine dinucleotide (FAD) • RDAs for males 19-70 years: 1.3 mg/day • RDAs for females 19-70 years: 1.1 mg/day • What foods contain riboflavin? Functions of Riboflavin • Flavoproteins provide most roles in the body: – Electron Transport Chain – PDHC – Beta oxidation – Various mineral and vitamin metabolism Riboflavin http://www.3dchem.com/molecules.asp?ID=63 Deficiency of Riboflavin • No clear deficiency, but can occur – Alcoholics – Congenital Heart disease – Some cancers http://www.wrongdiagnosis.com/phil/html/riboflavin-deficiency/3990.html Vitamin B3: Niacin • Water soluble vitamin B3 • Nicotinamide is a derivative of niacin and used to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) • RDAs – Males 19-70 years old 16 mg/day – Females 19-70 years old 14 mg/day • What foods contain Niacin? Functions of Niacin • Oxidation- Reduction Reactions – Krebs or TCA cycle – Glycolysis – Beta oxidation • Non-redox reactions – Mainly occurring in bacteria Niacin or Vitamin B3 Deficiency of Niacin • Usually occurring in developing countries • Primary deficiency: Pellagra – Extreme deficiency in both niacin and tryptophan – Most common physical attributes are dermatitis, diarrhea and dementia – Can be cured with supplements • Secondary deficiency: Alcoholism, Diarrhea and Cirrhosis http://www.merck.com/mmpe/sec01/ch004/ch004d.html Toxicity of Niacin • Sometimes used in large amounts to reduce LDL cholesterol and triglyceride levels and to increase HDL cholesterol • General symptoms are flushing Pantothenic Acid • Once referred to as Vitamin B5 • No RDAs, but AI or Adequate intake – Males and females >19 years: 5 mg • What foods is pantothenic acid found in? Pantothenic Acid • Functions: – Component of CoA – Participates in Cellular Metabolisms: • Carbohydrate • Protein • Lipid Pantothenic Acid http://commons.wikimedia.org/wiki/File:Pantothenic_acid_structure.svg Deficiency of Pantothenic Acid • Burning Feet Syndrome • Malnourished population: – Alcoholism – Diabetes – Inflammatory Bowel Disease Biotin • Also known as vitamin B7 • No RDAs, but Adequate Intake (AI) – Men and women >19 years of age: 30 µg • What foods contain Biotin? Functions of Biotin • Considered a coenzyme with: – Pyruvate Carboxylase – Acetyl CoA carboxylase – Propionyl CoA carboxylase Biotin http://www.chm.bris.ac.uk/webprojects2002/schnepp/biotin.html Deficiency of Biotin • Usually occurs when consuming raw eggs in excess amounts • Gastrointestinal disorders • Pregnancy • Genetic defects http://mark.asci.ncsu.edu/Nutrition/NutritionSlides/38.jpg Folate • Water soluble B-complex vitamin • Folic acid is the more stable form and not found in foods or humans, but in supplements and fortified foods • Folate containing molecules are found in foods and humans • RDA for folate: – Males and Females 14 years old+ 400 µg/day • What foods contain folate? Functions of Folate • Reproduction and maintenance of cells • Needed to make DNA and RNA • Needed to make red blood cells to prevent anemia in adults and children Folic acid http://healthlink.mcw.edu/article/984001430.html Fig. 9-28, p. 350 Folate Deficiency • What can happen with folate deficiency? – For pregnant women, can give birth to low weight, neural tube defect infants – Infants and children can have slow growth – What type of anemia may occur with both folate and vitamin B12 deficiency? Toxicity • Very uncommon in both foods and supplements due to it is a water soluble vitamin and can be excreted in the urine, but it can happen Vitamin B12 • Methylcobalamin and 5-deoxyadenosyl cobalamin are the forms of vitamin B12 used in the human body • RDA for males and females 19-70 years old 2.4 mcg/day • What foods contain Vitamin B12 ? Functions of Vitamin B12 • Cofactor for methionine synthase • Cofactor for L-methylmalonyl-CoA mutase – Cobalamin is the cofactor for this enzyme Vitamin B12 Vitamin B12 Necessary for Folate Function • Methylcobalamin is required for the function of the folate-dependent enzyme, methionine synthase • This enzyme is required for the synthesis of methionine from homocysteine Vitamin B12 Deficiency • Pernicious anemia • Food bound vitamin B12 malabsorption • Atrophic gastritis • Who may be more affected with vitamin B12 deficiency? Toxicity • None has been seen with food or supplements even as high as 1000mcg/day Vitamin B6 • 3 forms of vitamin B6 – pyridoxal (PL) – pyridoxine (PN) – pyridoxamine (PM) • The principal coenzyme factor, pyridoxal-5phosphate (PLP) has the most important function in humans • Must be obtained from the diet • RDAs for males and females 19-50 years old is 1.3 mg/day • What foods contain vitamin B6 ? Functions of Vitamin B6 • PLP is the main cofactor in multiple enzyme reactions for humans to function: – Nervous System: Neurotransmitters are synthesized with PLP- dopamine, serotonin – Red blood cell formation: Synthesis in heme – Niacin Formation: PLP synthesizes tryptophan to niacin – Hormone function: PLP binds to steroid receptors to inhibit the binding of steroid hormones – Nucleic Acid Synthesis: Coenzyme for mobilization in a single one carbon metabolism Vitamin B6 Deficiency • Uncommon, unless you are an alcoholic Toxicity • Usually when taking the form of B6 : pyridoxine in supplements over an extended period of time