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The Vitamins David L. Gee, PhD Professor of Food Science and Nutrition Central Washington University FCSN 245 - Basic Nutrition Dietary Supplement Use (USA) $ 4,300,000,000 for vit/min in 1995 $ 1,400,000,000 for herbs 35-40% adults regular users females > males 66% multi-vit/min 37% vitamin C 19% vitamin E Calcium supplements Dietary Supplement Use: Pros Supplements dietary deficiencies calcium folic acid Amounts used in some studies not attainable with dietary sources antioxidants Relatively low cost Dietary Supplement Use: Cons False sense of security folic acid and pregnancy Does not contain all potentially useful chemicals in foods Example: compounds found in plants that may be health promoting (phytochemicals) Toxicity almost only due to supplement use Costs significant low income Heavy users of supplements (athletes) Certain supplements are expensive Chondroitin sulfate – bone/cartilage: $30-50/mo SAMe – depression: $40-50/mo Exam 3 – Tuesday, March 6 Proteins and Amino Acids (chap 6) EAA, RDA, functions, athletes Genetically modified foods (p 472-480) Vegetarian diets Protein quality Protein deficiency (kwashiorkor/marasmus) Energy and Weight Loss (chap 9) Energy, TEE, BMR, factors affecting BMR, activity, TEF Calorimeters (bomb, direct, indirect) Weight loss, obesity risks, QOL, prevalence, high risk groups Healthy weight, assessment Calculate BMI, know cutpoints for blood pressure, sugar, lipids Dietary approaches (Balanced, Lo-Carb, restrained CHO, non-diet Exercise Drugs/Surgery Vitamin & Mineral Deficiency: A Global Progress Report UNICEF, 2004 80 developing countries studied Accounts for 80% of world population 1/3rd of world population do not reach their physical and intellectual potential because of vitamin/mineral deficiency Vitamin & Mineral Deficiency: A Global Progress Report UNICEF, 2004 Vitamin A deficiency 40% of children <5yrs with mild to severe deficiency Compromised immune deficiency blindness stunted growth Contributes to 1 million deaths of young children/yr A Solution: supplementation with betacarotene, 2x/yr, fortification of foods Vitamin & Mineral Deficiency: A Global Progress Report UNICEF, 2004 Iodine deficiency Goiter: enlarged thyroid gland, lethargy Cretinism: severe mental and physical retardation in infants of deficient mothers Reduces IQ by 10-15 points 80% of developing countries have goiter rates of > 10% A Solution: iodized salt (use declined from 75% to 65% in last decade!) Woman with iodine deficiency resulting In a goiter. Myxedematous endemic cretinism in the Democratic Republic of Congo : Four inhabitants aged 15-20 years : a normal male and three females with severe longstanding hypothyroidism with dwarfism, retarded sexual development, puffy features, dry skin and hair and severe mental retardation. Vitamin & Mineral Deficiency: A Global Progress Report UNICEF, 2004 Iron deficiency Anemia: fatigue, apathy in adults, poor academic performance in children (7-10pt drop in IQ) ~45% of children between 6mo-2 yrs 20 countries over 70% A solution Supplementation (bad taste, constipation) Fortification • Salt with iodine and iron • Vitamin/mineral mixes added to foods • Fortified foods The Discovery of Vitamins The Germ Theory of Disease Scurvy: Disease of sailors Beri-Beri: Disease of poor Asians The Discovery of Vitamins The Germ Theory of Disease Rickets: Disease of poor Northern European children Pellagra: Disease of poor corn eating cultures The Discovery of Vitamins The Vitamin Theory of Disease Scurvy: Disease of sailors Vitamin C deficiency Beri-Beri: Disease of poor Asians Thiamin deficiency Rickets: Disease of poor Northern European children Vitamin D deficiency Pellagra: Disease of poor corn eating cultures Niacin deficiency Vitamins: Definition Organic compound found in foods Required in small amounts Required in the diet (dietary essential) Proven to be required for health, growth, and reproduction deficiency syndrome identified Vitamin Nomenclature Fat soluble “A” & Water soluble “B” “Vital amines” vitamines = vitamins Vitamin B “complex” collection of water soluble vitamins that function as enzyme co-factors Vitamin C Vitamins D and E Mistaken Vitamins Fat and Water Soluble Vitamins Fat Soluble Vitamins (A, D, E, K) Soluble in lipids and solvents Excess stored and not excreted Excess may be toxic Deficiency slow to develop Fat and Water Soluble Vitamins Water Soluble Vitamins B vitamins, C Soluble in water excess excreted in urine, little stored generally less toxic deficiency develops quickly General Functions of Vitamins Hormones Vitamin D calcium homeostasis Vitamin A cell division and development General Functions of Vitamins Non-specific chemical reactions Vitamin E antioxidant Vitamin C chemical reducing agent General Functions of Vitamins Coenzymes or Cofactors chemicals that assist enzymes to function as catalysts B vitamins Vitamin C, A, K Vitamin A: types and sources Retinoids retinol, retinal, retinoic acid animal foods, milk fortification Carotenoids beta-carotene plants vitamin A precurser Vitamin A: functions Visual pigment: rhodopsin “night blindness” Maintenance of epithelial cells regulation of keratin protein synthesis Xeropthlamia intestinal malabsorption Bone and Immune System Development Vitamin A: Deficiency Common in developing countries 3 million children with severe deficiency blindness, poor growth and appetite 275 million children with mild deficiency impaired immunity Vitamin A: Toxicity 10 times RDA chronically 100 times RDA acute dose hair loss, joint pain, birth defects carotenoids are non-toxic toxicity due to vitamin supplement overdose Vitamin D: Types and Sources Dietary sources: animal foods, fortified milk Human Synthesis of Vitamin D Skin: cholesterol + sunlight “Sunshine Vitamin” – UV-B rays Vitamin D3 5-10 minutes, arms and legs, mid-day sun Liver & Kidney for activation 1,25-di-OH-D3 Final Exam – Winter 2007 Tuesday, March 15, noon 25% vitamins and minerals Lecture materials General info on vitamins/minerals Developing world vitamin/mineral deficiencies Required reading Chapter 7 (vitamin C ; vitamin A/carotenoids ) Chapter 8 (nutrients involved in bone health) Chapter (iron ; folate & B-12 ) Final Exam – Winter 2006 75% comprehensive “questions that you should know the answers to one or two years from now.” Study class notes Review old exams Vitamin D: Functions Helps regulate blood calcium levels When blood calcium levels are low, vitamin D (and other hormones): Increases dietary calcium absorption Decreases urinary calcium excretion Increases bone calcium mobilization Vitamin D: Deficiency Rickets bone deformities in children Osteomalacia weak bones due to low calcium content Vitamin D deficiency Calcium deficiency multiple pregnancies Vitamin D: Toxicity 5 times the RDA chronically calcification of soft tissue toxicity due to excessive vitamin supplementation Calcium Functions Bone Structure (99%) Regulator of Metabolism (1%) nerve impulse transmission muscle contraction blood clotting etc. Calcium Regulation of Blood Calcium 10 mg/dl of blood hypocalcemia & hypercalcemia abnormal muscle cramping nerve irritation Controlled by: vitamin D, parathyroid hormone, calcitonin Calcium RDA 1998 RDA’s (AI) 1300 mg/d : children & teens 1000 mg/d : adults 1200 mg/d : older Americans Usual intakes are low Osteoporosis Brittle, weak bones due to loss of total bone mass (minerals and protein) Prevalence 11% of > 65 yrs 22% of > 65 yrs in 20 yrs 24 million fractures/yr 200,000 hip fractures, 1/6 fatal 3D Visualization of data obtained by x-ray microtomography of the bone structure of the vertebrae of a 50 year old (left) and a 70 year old (right) This graph shows rates in the USA in 1984-87, adapted from Jacobsen, SJ in American J Public Health 80:872, 1990. An illustration of the consequence of osteoporosis on the spinal column. Elderly woman with dowagers hump, a marked abnormal curving of the spine caused by osteoporosis Other osteoporosis fact: National Osteoporosis Foundation - 2003 10 million with osteoporosis 18 million with low bone density 1 in 2 women will develop osteoporosis sometime in their life (1 in 8 men) Osteoporosis Risk Factors Genetics Family History Ethnicity Caucasian > Asian > Blacks Osteoporosis Risk Factors Gender associated with declines in estrogen production post-menopause anorexia, female athletes Undertreatment of Osteoporosis in Men with Hip Fracture. Arch. Int. Med. (Oct. 2002) 10 million Americans with osteoporosis 2 million are men Of 110 men hospitalized with hip fracture 4.5% received treatment for osteoporosis 1 year mortality was 32% Average age 80 yrs Of 253 women hospitalized with hip fracture 27% received treatment for osteoporosis 1 year mortality was 17% Average age 81 yrs Osteoporosis Risk Factors Chronic Calcium Deficiency Lack of Exercise Prevention of Osteoporosis Exercise Dietary Calcium “Rule of 300” 300 mg/d from plant sources 300 mg/d from each serving of dairy Prevention of Osteoporosis Other factors that may increase calcium loss high caffeine intake high protein intake high alcohol intake cigarette smoking Prevention of Osteoporosis Calcium Supplements Calcium carbonate least expensive Tums poor absorption Calcium citrate/malate (CCM) expensive, well absorbed Prevention of Osteoporosis Adequate amounts of vitamin D avoid excesses Hormonal replacement in high risk women http://www.mhhe.com/biosci/ap/mediacentral/nutrition_animations/osteoporosis_final.swf Folic Acid DRI (RDA): 1998 400 ug/d (180-200 old RDA) 600 ug/d pregnancy (400) Typical folate intake: 200 ug/d Dietary Sources foliage: fruits & vegetables Folic Acid Functions “single carbon metabolism” DNA synthesis (cell division) other reactions Folic Acid Deficiency Megaloblastic Anemia large abnormal red blood cells Elevated blood homocysteine CHD risk factor Folic Acid Deficiency Neural Tube Defects spina bifida - lower body paralysis required early in pregnancy Grain fortification (1998) will add 100-200 ug/d to diet Vitamin B-12 Cobalamine contains cobalt DRI (1998) : 2.4 ug/d (old 2 ug/d) Dietary sources: animal foods fortified cereals Vitamin B-12 Functions “single carbon isomerization” synthesis of DNA (folate interaction) nerve fiber sheath synthesis Vitamin B-12 Deficiency Pernicious Anemia megaloblastic anemia nerve injury peripheral weakness and numbness progressive degeneration to death concern among the elderly Vitamin B-12 Digestion and Absorption Requires functioning stomach “intrinsic factor protein” acid production B-12 and Folic Acid Excessive folic acid can mask nerve degeneration of pernicious anemia FDA regulates dosage of folate supplements FDA limited amount of folate fortification in grains Nutritional Antioxidants Oxidative Tissue Injury Oxygen free radicals unpaired electrons superoxide O2-. hydroxy free radical OH. hydrogen peroxide Oxidative Tissue Injury Causes chain reactive damage to: Cell membranes (hi PUFA) Proteins DNA Oxidative Tissue Injury Associated with: Coronary Heart Disease oxidized LDL-cholesterol Carcinogenesis Chemical Toxicity Auto-immune dieseases Aging Sources of Oxygen Free Radicals Normal energy metabolism nutrient + O2 --> CO2 + H2O + energy Electron transport system O2 --> H2O + energy but: O2 --> O2-. --> H2O + energy Sources of Oxygen Free Radicals D-amino acid metabolism D-AA --> C-skeleton + ammonia + H2O2 Metabolism of foreign chemicals drugs, pesticides, toxins, etc... Ozone, nitrogen oxides, UV light, smoke, radiation, etc... Cellular Antioxidants Antioxidant Enzymes Catalase (iron) removes hydrogen peroxides Superoxide Dismutase (Cu, Zn) removes superoxide radicals Cellular Antioxidants Antioxidant Enzymes Glutathione Peroxidase (Se) removes peroxides Mineral supplements are ineffective and may be toxic Cellular Antioxidants Nutritional Antioxidants Vitamin E Carotenoids and other plant phytochemicals Vitamin C Vitamin E Tocopherols Dietary sources: widespread, highest in plant oils Deficiency: rare in adults premature infants: hemolytic anemia Vitamin E Function: free radical scavenger in membranes RDA: 8-10 mg/d “Research dosages”: 400-800 mg/d Toxicity: rare, may be non-toxic below 1000 mg/d Plant Phytochemicals Beta-carotene & carotenoids Plant polyphenols garlic green tea grape skins cruciferous vegetables Antioxidants with “specific niches” Vitamin C Ascorbic Acid Food Sources fruits vegetables Deficiency: Scurvy poor wound healing impaired immune system Vitamin C Functions Antioxidant water soluble free radical scavenger Collagen synthesis connective tissue protein Synthesis of neurotransmitters, thyroxine, etc. Aids in absorption of dietary iron Vitamin C RDA : 60 mg/d RDA (smokers): 100 mg/d typical intake 100 mg/d “Effective research dosages” : 100-500 mg/d Vitamin C “Toxicity” > 1000 mg/d diarrhea kidney stones promotes “iron overload” toxicity Interfers with important lab tests blood in stools (colon cancer) urinary and blood glucose (diabetes) Iron Functions: Hemoglobin Myoglobin Iron enzymes catalase electron transport system Iron Deficiency Iron deficiency anemia fewer, smaller, paler red blood cells fatigue 5-10% of US premenopausal women up to 40% of population in developing countries Iron Deficiency Causes Blood loss menstrual blood loss parasites and bleeding ulcerations Inadequate dietary intake RDA men = 10 mg/d RDA women = 15 mg/d US usual intake 6 mg/1000 Cal Dietary Sources of Iron Heme Iron meats (Hb & Mb) 20-30% absorbed Non-heme Iron plants inorganic iron 1-10% absorbed vitamin C increases absorption iron cookware Iron Overload Toxicity Children (accidental poisoning) Men and post-menopausal women Genetic “defect” improved iron absorption Excess iron is a pro-oxidant. oxidized LDL-C tissue injury Iron Overload Toxicity May occur in 10% of men Treatment avoid iron containing supplements avoid excess vitamin C supplements bleeding or blood donation
