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