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Nutrients in Bone Health Calcium, vitamin D supplements good for bones – if you take them Bone Health • Bone structure – Provides strength to support the body – Allows for flexibility – Contains about 65% minerals providing the hardness of bone – Contains 35% organic structures for strength, durability, flexibility – Collagen: fibrous protein in bone tissue Bone Health • Bones develop through three processes: – Bone growth – increase in bone size; completed by age 14 in girls and age 17 in boys – Bone modeling – shaping of bone; completed by early adulthood – Bone remodeling – reshaping of bone Bone Health • Bone remodeling involves: – Resorption – surface of bones is broken down • Osteoclasts – cells that erode the surface of bones – Formation of new bone by cells called osteoblasts • Osteoblasts produce the collagen-containing component of bone Bone Health Calcium • Roles: – 99% in bones and teeth – 1% • Cell membranes: regulates transport of ions into and out of cells – Nerve to nerve transmission » Nerve to muscle transmission • Helps hold cells together • Blood Clotting • Co-factor for several enzymes Calcium: Blood Levels Highly Regulated: 4 ways • 1. Protein-bound Ca released to become available for use by cells • 2. Increased Calcium absorption from gut through activation of Vitamin D • 3.Increased Calcium released from the bone through parathyroid hormone activation of Vitamin D • 4. Kidneys conserve Calcium Calcium RDA 1000-1200 mg/day for Adults • Foods rich in Calcium: – – – – – 1 cup milk: 1 oz cheese: 1/2 cup spinach: 1 orange 1 cup Yogurt (fat free or low fat) 300 mg 200 mg 106 mg 52 mg 350-400mg Calcium Deficiency • Rickets: in children. Same as Vitamin D deficiency – Bow legs, poor bone formation • Osteomalacia: in adults. Same as Vitamin D deficiency – poor bone formation • Osteoporosis: Multiple causes Calcium and Osteoporosis • • • • • • • Low Calcium intake Poor Vitamin D status female family history small skeleton menopause smoking high animal protein drinking alcohol bed rest white/Asian MerckMedicus Modules: Osteoporosis - Pathophysiology Does your child have a drinking problem? Fruit and veg boosts bone strength during teenage years Vitamin D Functions • Works in three ways: – 1. Increases Calcium Absorption from the G.I. tract – 2. Helps to withdraw calcium from bone – 3. Increases calcium retention in the kidney. Sources of Vitamin D • Body makes it own: – Dehydrocholesterol in the skin exposed to sunlight • Energy transforms it into a pre-vitamin D molecule • Body heat provides energy to change pre-vitamin D into inactive Vitamin D • Inactive Vitamin D activated in two steps – First, in the Liver – Second in the Kidney Netrition Home Page Vitamin D Sources of Vitamin D RDA = 5 ug-15 ug • In foods: – – – – – Fortified milk: 2.5 mcg/cup 1 egg = 0.7 mcg 3 oz shrimp = 3 mcg 1 tsp margarine = 0.5 mcg USATODAY.com - How to get vitamin D? Vitamin D Deficiencies • In children: Rickets – malformed bones, bow legs • In adults: osteomalaciaVitamin D improves symptoms of knee osteoarthritis • most often occurs in women with low Ca intake, repeated pregnancies, low sun-exposure, and long breastfeeding with infants – loss of Calcium from bone and change of shape • USATODAY.com - Vitamin D reserach may have doctors prescribing sunshine Rickets: Vitamin D deficiency in Children Vitamin D Toxicity: • Most potentially toxic of all vitamins!!!! – As little as 4 to 5 X RDA can be associated with toxic symptoms • minor: diarrhea, headache, nausea • major: calcium deposits in soft tissues of heart, kidney, arteries – Major concern: those who take Vitamin D supplements • If some is good, more is NOT better!!!!! Vitamin K • Blood coagulation – coenzyme • Deficiency • Toxicity Phosphorus • Bone formation • Deficiency • Toxicity Fluoride • Becomes part of crystalline deposits in bones and teeth – In teeth, resistant to tooth decay (dental caries) – 1 part per million in water supply optimum resistance – Higher than that can result in tooth mottling • Brown coloration on teeth – Much higher (18 ppm) can result in fluoridosis • Bone malformation Tracking Fluoride in the National Food Supply / November 9, 2004 / News from the USDA Agricultural Research Service Nutrients in energy metabolism and blood health B Vitamins • • • • • • • Correct names and common names Thiamin B1 Riboflavin B2 Niacin nicotinic acid B6 pyridoxine folacin folate, folic acid B12 cobalamin B vitamins: Correct names • pantothenic acid • biotin no other no other • B vitamins act as coenzymes – Help to complete the correct shape of the molecule – Many help to metabolize glucose to release energy B Vitamins • Coenzyme function – Prosthetic Group: physically become part of an enzyme complex – Others are more loosely attached – May be part of the active site in the enzyme. Vitamins and Metabolism B Vitamins • • • • Thiamin Riboflavin Vitamin B 6 (pyridoxine) Folate B vitamin deficiencies • Thiamin: beriberi – symptoms: mental confusion, muscle weakness and wasting, edema, enlarged heart • Riboflavin: – symptoms: personality changes, cracks at the corners of your mouth(cheilosis), tender tongue(glossitis) • Folacin: – Symptoms: megaloblastic, macrocytic anemia, Niacin • Part of NAD+ – helps metabolize glucose – without Niacin, this breakdown of glucose stops – Slows energy release: 4 D’s of Niacin deficiency (called pellagra: • • • • Dermatitis: skin inflammation Diarrhea: poor absorption Dementia: no energy to think Death: if untreated Vitamin B 12 • • • • Blood formation Homocysteine Nerve damage Deficiency – Atrophic gastritis – Pernicious anemia Megaloblastic anemia Vascular Disease • Folate and vitamin B12 are required for the breakdown of the amino acid homocysteine. • Low folate and vitamin B12 intake may cause an increased level of homocysteine. • High homocysteine levels are associated with greater risk of cardivascular and cerebrovascular disease. B vitamin Toxicities: Rare • B6 – Symptoms: with very high doses sensory nerve disorders; may interfere with nerve impulses and heart beat • Niacin – Symptoms: skin flushing, nausea, jaundice, liver dysfunction • Some individuals with high serum cholesterol are treated with pharmacological doses of niacin Iodine • Regulator – Thyroid hormones • Deficiency • Toxicity Iodine Deficiencies http://www.forbes.com/forbeslife/he alth/feeds/hscout/2006/06/28/hscout 533494.html Blood Health Trace Minerals: Micro minerals • One definition: less than 0.1 gram(100 mg/day) need in the diet – Some trace minerals: • Iron (Fe) • Zinc (Zn) • Copper (Cu) Iron • Component of hemoglobin and myoglobin – hemoglobin carries oxygen in blood – myoglobin stores oxygen in muscle cells • Deficiency: – RDA set at 18 mg/day for females and 8 mg/day for males – If iron stores exhausted, iron deficiency anemia • microcytic, hypochromic anemia • reduced Hemoglobin synthesis, RBCs are small and Iron Iron Absorption • Most iron we eat doesn’t get absorbed – What helps? • vitamin C • MFP factor: some factor in meat, fish and poultry helps absorb iron • need for iron – What hurts absorption? • tea coffee • Calcium and Phosphorus • phytates and fiber and oxalates Factors Affecting Iron Absorption • Increase • Decrease • • • • • • • • • • • • • Gastric Acid Heme iron Demand Low body stores MPF Vitamin C Phytic Acid Oxalic Acid Polyphenols Full body stores Excess of other min. Reduced gastric acid Some antacids Iron: Method of Absorption • Iron in food – Absorbed into cells that line GI tract – If blood levels of iron are low • iron picked up from cells by the blood and carried to places where RBCs are made – If blood levels of iron are ok • iron stays in cells lining the GI tract – In 3 to 5 days the cells are worn out and fall into the lumen of the GI tract and mix with the remains of digestion Iron Absoption Iron Overload • 2 Types of Overload – 1. Hereditary Defect: Hemochromatosis • Very efficient absorption • High circulating Fe which is laid down in tissues of liver, heart and causes damage – 2. High Iron ingestion: Hemosiderosis • Even with control of absorption, high intake can result in toxic side effects • We don’t have a good mechanism of getting rid of absorbed iron Iron Sources • • • • • • 4 oz of lean roast = 3 mg 4 oz liver = 7 mg 1/2 cup beans = 4.15 mg 1 cup broccoli = 1.12 mg 1 slice mixed grain bread = 0.8 mg 1 cup raisins = 3.12 mg Zinc • Part of nearly 100 enzymes • Role in immune function • Absorption affected by zinc status, phytates, iron • Hinders absorption of copper and iron • Sources: red meats, eggs, vegetables Zinc Deficiency • • • • • • • Growth delay Altered digestive function Impairs immune response Vitamin deficiencies Loss of appetite Slow wound healing Dry, scaly skin Copper • Coenzyme – Part of ceruloplasmin • Deficiency • Toxicity