nutrients in bone health calcium, vitamin d supplements good for bones – if you take them calcium,...
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Nutrients in Bone HealthCalcium, 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: 300 mg– 1 oz cheese: 200 mg– 1/2 cup spinach: 106 mg– 1 orange 52 mg– 1 cup Yogurt 350-400mg
(fat free or low fat)
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: Rickets: Vitamin D Vitamin D deficiency deficiency
in in ChildrenChildren
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 no other• biotin 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 Deficiencieshttp://www.forbes.com/forbeslife/health/feeds/hscout/2006/06/28/hscout533494.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
pink
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• Gastric Acid• Heme iron• Demand• Low body stores• MPF• Vitamin C
• Decrease• 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
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