Secreted in response to low blood calcium

Stimulates inactive form of vitamin D to calcitriol

Both increase blood calcium by small intestines, increasing bone breakdown, and decreasing calcium excretion in the urine

stimulates blood clotting

muscle contractions

transmission of nerve impulses

cofactor for energy metabolism

Bones - provide structure; site of red and white blood cell production

5th week of gestational development growth starts (fetal bones made of cartilage)

7th week - ossicication

Periosteum - outer covering of bone; made of connective tissue, blood vessels, nerves

Cortical Bone - provides strength

Trabecular bone - contains bone marrow

Core of each bone contains: blood vessels, lymphatic vessels, nerves

Bone-forming cells responsible for depositing minerals and proteins; bone maintenance, growth, repair

Growth - increase in size; complete by age 14 (F) and 17 (M)

Modeling - shaping of bone; complete by early adulthood; exercise and overweight increase thickness

Remodeling - recycling of bone tissue

Bone mass and mineral density decline after age 30

calcium absorption and vitamin D production, absorption, and metabolism decreases with age

Estrogen - important for bone strength

Menopause - loss of 1-3% bone mass/year

initial stage of osteoporosis

Bone minerals are lost, but overall matrix remains intact

Chronic Disease

Loss of bone mineral and matrix

Gender - females at greater risk

Age - increase after 40yo

Body size: BMI<19

Ethnicity - northern european and asians at more risk

Genetics - children of parents with osteoporosis

Influenced by: geneticcs, nutritional status, nutrient interactions, aging

Deficiencies and toxicities rare - typically from a failure to trive and grow

Heme iron - shellfish, beef, poultry, organ meats; makes up hemoglobin, myoglobin, cytochromes

Nonheme iron (85%) - green leafy vegetables, mushrooms, legumes, enriched grains

Vitamin C and stomach acid: convert ferric to ferrous iron

Chelators: phytates, polyphenols (some veggies, tea, coffee, red wine), calcium and phosphorous in milk

transferrin - in blood stream delivers iron to body cells

ferritin - in intestinal cells, main storage form

absorption dependent on storage of iron

hemosiderin - insoluble iron-protein stored in the liver, long term storage

oxygen transport: hemoglobin

Iron reservoir: myoglobin

cellular energy metabolism

Most common

Groups most at risk: infants, growing children, pregnant women

Mild deficiency: fatigue, impaired work performance, behavioral abnormalities

Severe deficiency: microtic hypochromic anemia

small, pale red blood cells

decreased ability to carry oxygen

decreased ATP synthesis

Hemoglobin conc: M<13g/L ; F<12g/L

Hemotocrit (%red cell volume): M<39% ; F<36%

Ferrous Iron - best absorbed

Other terms: ferrous fumarte, ferrous sulfate, ferrous, gluconate

Medicinal or supplemental iron

Most common cause of childhood poisoning

excess deposited in liver, heart, muscles

Symptoms: vomiting, diarrhea, constipation, black stools, death due to resspiratory collapse

Higher requirements for pregnant women, periods of rapid growth/development

RDA: men = 8mg/day; F=18mg/day; pregnant=27mg/day

UL: 45mg/day

Vegans - 80% higher, iron supplements

Athletes - increased blood loss in feces/urine, chronic rupture of red blood cells in feet; needs are 70% higher

Essential trace mineral

acts as a cofactor for nine enzymes involved in redox rxns

2 forms: Cupric (oxidized) and Cuprous (reduced)

Best sources - organs, shellfish, whole-grains, mushrooms, nuts, legumes

bioavailability decreases with antiacids, iron

Absorbed in small intestine and stomace (influenced by Cu status)

Ceruloplasmin - protein that transports copper in blood

Excess copper incorporated into bile (eliminated in feces)

Cytochrome c oxidase - copper-containing enzyme needed in ETC for ATP production

Superoxide dismutase - copper-containing enzyme that reduces superoxide free radical (O2-) to hydrogen peroxide; antioxidant function

Usually a consequence of high zinc supplements

Normocytic, hypocromic anemia

Rare genetic disorder affect Cu status: menkes disease

Not common (storage of Cu is tightly regulated)

Wilson's disease - accumulates copper in the liver, brain, kidneys, and cornea leading to premature death if lead undetected

Forms: iodine (form in food); iodide (form in body)

Absorbed in small intestine and stomach

Taken up by thyroid gland

Thyroid-stimulating hormone regulates uptake

Synthesis of T4

T4 is converted to T3 (active hormone)

T3 regulates basal metabolic rate, production of body heat energy, human growth

Development in the CNS

Cretinism - affects babies of iodine-deficient mothers; severe retardation

Goiter - enlarged thyroid gland

1920s - "Goiter Belt"

Statewide Campains

Started providing iodized salt to children

Goider almost eliminated

Current - public health working to eradicate goiter internationally

Essential trace mineral involved in gene expression, immune function, and cell growth

Chocolate is a good source

Absorption requires 2 proteins: One transports Zn into enterocyte; metallothionine binds zinc within cell

Excess excreted in feces

Cofactor: zinc containing 3D structures allows proteins to regulate gene transcription

Wound healing

Antioxidant

Tast acuity

sexual development

Acrodermatits Enteroathica

Genetic abnormality - defective transport protein decreases zinc absorption

growth failure, red/scaly skin, diarrhea

fatal if untreated

upper limit is 40mg/day

inhibits copper absorption, reduces HDL, increased risk of heart disease, nausea, vomiting, loss of appetite

RDAs: men = 11mg/day

women = 8mg/day

vegetarians/vegans = 50% more zinc than non

Not an essential nutrient

Dietary fluoride strengthens bones and teeth

foods provide little fluoride (poatoes, tea, legumes, fish)

Communities add fluoride to tap water

American dental association recommends water fluoride at 0.7 to 1.2ppm

Almost all fluoride consumed is absorbed by small intestine and circulates in blood

taken up by teeth and bone

excess excreted in urine

strengthens bone and teeth matrix

stimulates maturation of osteoblasts

topical application decreases bacteria in mouth, reduces dental cavities

GI upset, excessive production of saliva, watery eyes, heart problems, coma

dental fluorosis and skeletal fluorosis

special concern for children who swallow toothpaste