Chapter 7 Vitamins. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 1

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Chapter 7 Vitamins Copyright 2009, by Mosby, Inc.

2 Key Concept Vitamins are noncaloric essential nutrients necessary for many metabolic tasks and the prevention of associated deficiency diseases. Certain health problems are related to inadequate or excessive vitamin intake. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 2

3 Key Concepts Vitamins occur in a wide variety of foods that are packaged with the energy- and tissue-building macronutrients (carbohydrate, fat, and protein). The body uses vitamins to make coenzymes required for some enzymes to function. The need for particular vitamin supplements depends on a person s vitamin status. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 3

4 Discovery: Early Observations Discovered (first vitamin) while searching for cures for classic diseases Dr. James Lind and scurvy Sailors dying on long voyages without fresh food Lemons and limes provided, no one became ill British soldiers got the nickname limeys Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 4

5 Discovery: Early Animal Experiments Dr. Frederick Hopkins of Cambridge University Two groups of rats Group 1: Fed synthetic mix of protein, carbohydrate, fat, mineral salts, and water All rats died Group 2: Fed same ration but with purified milk All rats grew normally Proved that accessory factors are present in natural foods that are essential to life Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 5

6 Era of Vitamin Discovery Most vitamins were discovered in the first half of the 1900s At first scientists assigned letters of the alphabet to each vitamin A, C, D, E, K This practice was abandoned in favor of more specific names based on structure and function Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 6

7 Definition of Vitamin 2 characteristics to define: It must be a vital, organic substance that is only necessary in extremely small amounts It cannot be manufactured by the body in sufficient quantities to sustain life, so it must be supplied by diet Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 7

8 Function of Vitamins Metabolism: Enzymes and coenzymes Coenzymes are derived from vitamins and are integral parts of some enzymes Example- B vitamins are part of coenzymes Enzymes act as catalysts Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 8

9 Functions of Vitamins, cont d Tissue structure and protection Vitamin C- involved in synthesis of collagen Antioxidants- protect cell structures Prevention of deficiency diseases Scurvy- C Beriberi- B 1 Pellagra- B 3 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 9

10 Vitamin Metabolism Fat soluble Vitamins incorporated with absorbed fat and transported by chylomicrons Best absorbed when eaten with fat May be stored for long periods A, D, E, and K Water soluble Easily absorbed and transported by the portal circulation Not stored, so must be eaten on regular basis (exceptions: B 12 and B 6 ) Vitamin C and all the B vitamins Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 10

11 Fat-Soluble Vitamins: Vitamin A (Retinol) Functions Vision Tissue strength and immunity Skeletal and soft tissue growth Deficiency disease: Xerosis- itching, burning, inflamed eyelids Xerophthalmia- blindness, severe deficiency Toxicity symptoms- joint pain, thickened bones, hair loss, jaundice Food sources (page 97)- milk, eggs, meat, sweet potato, carrots, cabbage Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 11

12 Vitamin D (Cholecalciferol) Functions Absorption of calcium and phosphorus Bone mineralization Deficiency disease: Rickets -bone malformation Osteoporosis Toxicity symptoms- calcification of soft tissues, reduced kidney function Food sources- yeast & fish, fortified milk and cereal (page 99) Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 12

Child with Rickets Copyright 2009, by Mosby, Inc.

14 Vitamin E (Tocopherol) Functions Antioxidant function- prevents changes in cell membrane structures Protects RBCs- prevents lysis Deficiency disease: Hemolytic anemia- premature infants disrupts normal myelin production in adults Toxicity symptoms- food-none, supplementsinterferes with blood clotting Food sources- page 101- bread, almonds, oils Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 14

15 Vitamin K Functions Blood clotting Bone development Deficiency disease: unlikely, except in clinical conditions related to clotting, malabsorption, intestinal bacteria Toxicity symptoms- no UL Food sources- page 102- green leafy veggies Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 15

16 Water-Soluble Vitamins: Vitamin C (Ascorbic Acid) Functions Connective tissue- collagen General body metabolism- increased need when sick Antioxidant function Deficiency disease: Scurvy (joint and tissue bleeding) Toxicity symptoms- rare, diarrhea Food sources- citrus, melons, veggies, page 105 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 16

17 Thiamin (Vitamin B1) Functions energy extraction from glucose fat synthesis for energy storage Deficiency disease Beriberi- paralyzing, Asian countries Wernicke s encephalopathy- alcohol inhibits absorption Toxicity symptoms- no UL Food sources- page 106- lean pork and beef, enriched grain Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 17

18 Riboflavin (Vitamin B2) Functions Energy production Tissue protein building Deficiency disease- ariboflavinosis- tissue breakdown and poor wound healing, cracked lips Toxicity symptoms- no UL Food sources- page 107- milk, meats, green veggies Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 18

19 Niacin (Vitamin B3) Functions Energy metabolism Healthy Skin Deficiency disease: Pellagra- dermatitis, diarrhea, dementia, death (corn-staple food) Toxicity symptoms- none from food, but from supplements- burning, itching of skin Food sources- fortified cereals and grains Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 19

Niacin Deficiency: Pellagra Copyright 2009, by Mosby,

21 Vitamin B6 (Pyridoxine) Functions Protein metabolism Neurotransmitter synthesis Deficiency disease- unlikely, CNS Toxicity symptoms- none from food, but supplements- nerve damage and lack of coordination Food sources- widespread, but grains and meats, page 110 Can be stored in muscle Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 21

22 Folate Function DNA synthesis Hemoglobin synthesis Amino acid synthesis Deficiency diseases: pregnancy Megoblastic anemia Neural tube defects- spina bifida Toxicity symptoms- not from foods; supplementsmask B 12 deficiency Food sources- widespread- green leafy veggies, liver, legumes, page 111 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 22

23 Cobalamin (Vitamin B12) Functions Synthesis of nonprotein heme portion of hemoglobin Proper nervous system functioning Deficiency disease: Pernicious anemiarare, but vegans susceptible Toxicity symptoms- no UL Food sources- mostly animal productsmeat and dairy, page 113 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 23

24 Pantothenic Acid Functions Needed to extract energy from all macronutrients- Acetyl CoA Deficiency disease: Unlikely Toxicity symptoms- no UL Food sources- all plants and animal cells, page 114 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 24

25 Biotin Functions Synthesis of fatty and amino acids Deficiency disease: No natural deficiency known Toxicity symptoms- no UL Food sources- widespread- egg yolk, liver, eggs, nuts Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 25

26 Choline Data insufficient to determine its essentiality to the diet Functions Structural integrity of cell membranes Neurotransmission- acetylcholine Deficiency disease: Liver damage Toxicity symptoms- excessive supplementslow growth rate, lowered BP Food sources- milk, eggs, liver, peanuts Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 26

27 Phytochemicals Bioactive molecules with health benefits Act as antioxidants or hormones Some researchers believe there are more than 25,000 phytochemicals, many of which have yet to be identified. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 27

28 Phytochemicals, cont d Functions Reduced risk of chronic disease Protection against coronary heart disease Improved overall colon function Prevention of age related macular degeneration Cancer prevention Increased antioxidant status Recommended intake- NCI, 5-9 servings/day Food sources Seven colors with corresponding phytochemicals Veggies, fruits, nuts, seeds, grains, soy, legumes Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 28

29 Vitamin Supplementation Ongoing debate Biochemical individuality- body s chemical composition is not the same for everyone Life cycle needs Pregnancy and lactation Infancy Children and adolescents Aging Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 29

30 Vitamin Supplementation, cont d Lifestyle Oral contraceptive use- lowers serum levels of C and several B vitamins Restricted diets- vegetarian needs B 12 Exercise programs- riboflavin (B 2 ) Smoking- C Alcohol- thiamin, folate, B 6 Caffeine- B s and C Disease Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 30

31 Vitamin Supplementation, cont d Megadoses Toxic effects- GI and kidney problems Artificially induced deficiencies Toxicity higher in fat soluble vitamins Supplementation principles Read labels carefully Vitamins CAN be harmful in large amounts Keep individual needs in mind Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 31

32 Summary Vitamins are food substances required in very small amounts. Body cannot make vitamins, but a well-balanced and varied diet usually supplies sufficient intake. Fat-soluble vitamins are A, D, E, K. Water-soluble vitamins are C and B- complex. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 32

33 Summary, cont d Possibility of toxicity is increased for fatsoluble vitamins compared with watersoluble vitamins. Water-soluble vitamins ascorbic acid (C) and pyridoxine(b6) in megadoses can be harmful. Phytochemicals are found in whole and unrefined plant foods. Nutrition supplementation is a controversial subject. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 33

35 Key Concepts The human body requires a variety of minerals in different amounts to perform numerous metabolic tasks. A mixed diet of varied foods and adequate energy value is the best source of the minerals necessary for health. Of the total amount of minerals a person consumes, only a relatively limited amount is available to the body. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 35

36 The Nature of Body Minerals Classes of body minerals- amount in body Major minerals (in take of >100 mg/day) Trace elements (in take of <100 mg/day), no less important, just less in the body Functions of minerals- metabolism Digestion Absorption Transport Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 36

38 Calcium Functions Bone and tooth formation Blood clotting: fibrinogen à fibrin Muscle and nerve action Metabolic reactions Absorption B12 Insulin secretion Activate pancreatic lipase Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 38

39 Calcium, cont d Requirements 1000 mg/day Deficiency states Osteoporosis Cardiac arrhythmia (if severe) Toxicity symptoms- kidney stones, interference Food sources Milk is the major food source Green vegetables, fish with bones, fortified food Page 129 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 39

Osteoporosis Copyright 2009, by Mosby, Inc.

41 Phosphorus Functions Bone and tooth formationhydroxyapatite in matrix Energy metabolism- phosphate (It s the P in ATP!) Acid-base balance- buffer Important building block in DNA/RNA Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 41

42 Phosphorus, cont d Requirements 700 mg/day Deficiency states- (Rare) bone loss, weakness Toxicity symptoms- bone breakdown-rare Food sources- all plants and animals, high protein foods Milk, milk products, fish, eggs Page 131 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 42

43 Sodium Functions Water balance- major extra-cellular ion, osmosis Action Potential! Acid-base balance- salt Muscle action Nutrient absorption- glucose transporters in intestine are sodium dependent Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 43

44 Sodium, cont d Requirements AI: 1.5 g/day UL: 2.3 g/day Deficiency states- rare, heavy sweating Toxicity symptoms Salt sensitivity and hypertension, edema Food sources Table salt, cured meat, canned soups, processed food Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 44

45 Potassium Functions Water balance- major intracellular ion, keeps water inside cells Metabolic reactions- glucose to glycogen Muscle action- heart is sensitive, relaxant Action Potential (Repolarization) Insulin release Blood pressure- if K = Na, may prevent Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 45

46 Potassium, cont d Requirements AI: 4.7 g/day Deficiency states- not from intake, but vomiting or diarrhea, diuretics (potassium sparing) Toxicity symptoms- no UL, weak heart Food sources- page 134 Fruits, vegetables, whole grains, fresh meats Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 46

47 Chloride Functions Digestion Key element in hydrochloric acid secretion Respiration Helps RBCs move CO 2 for release, maintains negative charge balance (bicarbonate ion, HCO 3- ) Counterbalances HCO3- (Anion Gap) Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 47

48 Chloride, cont d Requirements AI: 2.3 g/day Deficiency states- excessive fluid loss through vomiting Toxicity symptoms- no UL, severe dehydration (causes high concentration) Food sources Table salt Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 48

49 Magnesium Functions General metabolism- cofactor for 300+ enzymes Protein synthesis Muscle action Basal metabolic rate- secretion of thyroid hormone Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 49

50 Magnesium, cont d Requirements ~300 to 400 mg/day Deficiency states- rare, vomiting, diarrhea Toxicity symptoms- rare, but would cause vomiting, diarrhea Food sources Nuts, soybeans, cocoa, seafood, peas, green vegetables Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 50

51 Sulfur Functions Hair, skin, and nails (Building block of some amino acids!) General metabolic functions Vitamin structure- thiamin(b1), biotin Collagen structure- connective tissue Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 51

52 Sulfur, cont d Requirements Not stated (in foods with protein) Deficiency states- none reported Toxicity symptoms-no UL, unlikely Food sources Meat, nuts, soy, fish, cheese, eggs Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 52

53 Trace Elements Iron Iodine Zinc Selenium Fluoride Copper Manganese Chromium Molybdenum Cobalt Boron Vanadium Nickel Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 53

54 Iron Functions Hemoglobin synthesis- 70% General metabolism- glucose, antibodies, liver Requirements 8 to 11 mg/day for males 8 to 18 mg/day for females Deficiency states Anemia- 2 billion worldwide Toxicity symptoms- large dose, UL is 45 g/day Food sources- page 140, meat, cereal (fortified) Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 54

56 Iodine, cont d Deficiency states Goiter Cretinism- dwarfism, retardation Hypothyroidism- myxedema, weight gain from not enough T4 Hyperthyroidism- excessive T4, Graves disease, exopthalmic goiter Toxicity symptoms UL of 1100 mcg/day Food sources Iodized table salt, seafood Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 56

58 Zinc Functions Enzyme constituent Immune system- lymphocytes Other functions Taste/smell, wound healing Protects RBCs Requirements 11 mg/day for males 8 mg/day for females Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 58

59 Zinc, cont d Deficiency states Poor wound healing Impaired taste and smell Toxicity symptoms- nausea, vomiting, decreased immunity Food sources Meat, seafood, legumes, whole grains Page 143 Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 59

60 Selenium Functions Aids in protection from free radicals Requirements RDA: 55 mcg/day Deficiency states- may decrease ability to fight infection, cancer Toxicity symptoms- brittle hair/nails, GI upset, rash, UL- 400 mcg/day Food sources Seafood, kidney, liver; depends on soil content Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 60

61 Other Trace Elements Fluoride Functions by preventing dental caries Copper Iron twin, energy production & hemoglobin Manganese Enzymes, inhalation toxicity Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 61

62 Other Trace Elements, cont d Chromium Previously thought to reduce insulin resistance- no evidence Molybdenum- catalyst Inadequate dietary intake improbable Other essential trace elements Aluminum, arsenic, boron, nickel, silicon, tin, vanadium, cobalt Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 62

63 Mineral Supplementation Life cycle needs Pregnancy and lactation Adolescence Adulthood Clinical needs Iron-deficiency- anemia Zinc deficiency- observed in alcoholics, vegans, elderly, children Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 63

64 Summary Minerals are single, inorganic elements. Minerals are classified according to their relative amounts in the body. Major minerals make up 60% to 80% of all inorganic material in the body. Trace elements make up less than 1% of the body s inorganic material. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 64

65 Summary, cont d RDAs have not been set for all minerals. Als or ULs have been set for almost all essential minerals without RDAs. Mineral supplementation is still under much debate. Copyright 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved. 65

Vitamins are noncaloric essential nutrients necessary for many metabolic tasks and the prevention of associated deficiency diseases.

Chapter 7 Vitamins Chapter 7 Lesson 7.1 Key Concept Vitamins are noncaloric essential nutrients necessary for many metabolic tasks and the prevention of associated deficiency diseases. Dietary Reference