Micronutrients involved in Bones and Blood Flashcards Preview

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Flashcards in Micronutrients involved in Bones and Blood Deck (51):

Why Are Bones Important?

-Support for the body
-Protects our organs (ribs, skull, vertebrae)
-Support for muscles- muscles attach to bones
-Storage reservoir for calcium, phosphorus and fluoride
-Blood cells are produced in the marrow of our bones

Nutrients involved in bone health: calcium, Vitamin D, Phosphorus, magnesium, fluoride, Vitamin K


Bone Composition

-Minerals calcium & phosphorus
*Comprises majority of bone- 65%
*Crystallize to hydroxyapatite crystals → hardness of bone
-Protein fibers made of collagen
*Comprises 35% of bone
*Strength & flexibility of bone


Bone Development

Remodeling: building & breaking down of bone
- Continuously occurring in adults
-Allows for release of Ca and P in the blood
-Allows for repair of damaged areas


Bone Growth

- Determines bone size
- Begins in the womb
- Continues until early adulthood


Bone Modeling

- Determines the bone shape
- Begins in the womb
- Continues until early adulthood


Bone Remodeling

- Maintains integrity of bone
- Replaces old bone with new bone to maintain mineral balance
- involves bone resorption and formation
- occurs predominately during adulthood


Cells Involved in Bone Remodeling

-Osteoclasts: dissolve bone, resorption, “crushing”
-Osteoblasts: bone “building” cells
-Osteocytes: fully matured osteoblasts, bone cells


Phases of Bone Development Throughout Life

-Teens: bone growth achieved ~14 yo for girls & ~17 yo for boys

-Early adulthood: add bone density but max. reached by 30
~ 90% of body density reached by the age 17 for women and 20 for men
-35 & older: bone density begins irreversible decline



-Most abundant mineral in our body

- provide structure to bones and teeth
-acid-base balance (Ca basic)
-transmission of nerve impulse
-muscle contraction
-regulation of hormones & enzymes
-blood clotting


Calcium Absorption

-Absorption via passive & active transport (Vitamin D)
-Acidic environment
*Older adults with atrophic gastritis (~10-30% in 50s, 40% 80s), reduced HCL, consume with a meal
-↑ absorption in times of greater need
*Absorption ~30% for healthy adults, ~60% in pregnancy, infants, children, adolescents
-↑ intake ↓ absorption (and the reverse)
*Maximum absorption ~ 500mg at a time
-Dietary binders but not enough to cause deficiency
*Phytates (legumes, rice, grains), oxalates (spinach, teas), minerals (iron)


Blood Levels of Calcium Are Tightly Regulated

Think for a minute, how might our bodies regulate calcium?
-Storage: bones
-Excretion: kidneys
-Absorption: GI


RDA & Food Sources for Calcium

-RDA established in 2010
*9-18 yo = 1,300 mg/day
*19-50 yo = 1,000 mg/day
*Older men & women: 1,200 mg/d for

-Many women & adolescents are below the RDA

-Nutrient of concern in the U.S.


Calcium Toxicity

-Supplemental form
*Increase the risk of calcification of soft tissues
~Meta-analysis of 12,000 people from 15 studies found supplemental calcium (without D) increased the risk of heart attack by 30%. (BMJ. 2010 Jul 29;341)
~WHI data reanalyzed and found same association (with or without D) (BMJ. 2011 Apr 19;342)
*Mineral imbalances: iron, zinc, magnesium
*Kidney stones: calcium deposits


Calcium Deficiency

-↓ bone density (mineralization)
-Children: stunted growth
-Adults: osteoporosis
*Low bone mass, deterioration of bone tissue
*Porous brittle fragile bones- ↓ ability to put weight on the bone
*High risk of spine and pelvic fractures
*Loss of height

--Loss of bone in spine= compression of the spine
-Kyphosis: hunching of the spine


Factors Affecting Risk of Osteoporosis

-Genetics: family history, race (Caucasian and Asian at higher risk)
-Female gender: lower bone density, menopause, live longer
-Aging: reduced estrogen and testosterone, ↓ stomach acidity, ↓ physical activity, ↓ vit D synthesis
-Body size
-Smoking: direct toxic effect on the bone
-Low peak bone mass: “A pediatric disease with geriatric consequences”
-Calcium, vitamin D intake
Emerging data: high caffeine intake (>3c coffee/d) in elderly


Management & Prevention

No cure for osteoporosis but drugs can slow or reverse some bone loss

Prevention by maximizing peak bone mass before early adulthood
-Optimal calcium & vitamin D
-Active lifestyle: weight bearing exercise- strength training, running, stair climbing


Vitamin D

-Fat soluble vitamin
-Is it essential?
*Depends where you live. If you live in a place with lots of sun, than no. But if you leave in a place that has no sun, than yes, the vitamin D is essential
*Regulates blood calcium, what are the 3 ways it works with PTH to increase blood calcium?
~Enhance osteoclast activity (crush bones)
~Increase calcium absorption
~Increase blood calcium by signaling the kidneys to not secrete so much calcium and absorb it
*Maintain bone health
~↑ Ca absorption and
~Assists with crystallization of Ca & Phos into hydroxyapatite crystals
*Role in cancer and heart disease


RDA: Vitamin D

-1-70 y.o.= 600 IU ->70 y.o.= 800 IU
-Many experts suggest 800-2,000 IU
-UL vitamin D is 4,000 IU
-Average intake
men: 200-288 IU Women:144-276


Vitamin D & Food

-Forms in food
*Ergocalciferol (D2) in plants (inactive form)
*Cholcalciferol (D3) in animal foods (active form)
-Fatty fish (salmon, mackerel, sardines), cod liver oil, milk, fortified dairy, fortified cereals

-1 Tbs cod liver oil: 1,360 IU
-3 oz sockeye salmon: 375 IU
-Tuna in oil (3 oz): 200 IU
-Total fortified cereal (3/4 c): 100 IU
-1 c milk: 80 IU (all milk in US is fortified with vit D)
-1c fortified yogurt: 80 IU


Sunlight & Vitamin D

Enhanced synthesis:
- June & July
-Sunny, no clouds or smog
-Latitude: closer to equator (changes at 40 deg N or S)
-9-3 pm
-younger age
-SPF<8 (above 8 reduces synthesis)
-exposed skin (clothing blocks)
-lighter skin color

~3,000 IU from 5-10 min mid-day mid-year sun exposed on arms & legs, weight the pro against risk of skin cancer


Vitamin D: Toxicity

From supplementation not from sun (skin breaks down excess, limits production)

-↑ blood calcium levels
-Calcium deposits in heart, liver, kidney
-Can be fatal


Vitamin D: Deficiency

*Inadequate mineralization, soft bones
*Bowed legs



Risk of Vitamin D Deficiency

High risk people include:
-Breastfed infants
-Older adults: 4x ↓ ability to synthesize
-Darker pigmented adults: need more sun time
-Those with limited sun exposure
-Those with fat malabsorption
-Gastric bypass
-Obese (Vit D gets stored in the fat tissues and not in blood)
-Kidney and liver disease patients (two organs activate Vit D)



-Calcium and Phosphorus crystallize to form hydroxyapatite crystals → hardness of bone

-Principle intracellular anion (electrolyte), aids in cellular fluid balance
-Part of ATP
-Activates & deactivates enzymes
-Part of DNA, RNA, cell membranes & lipoproteins as phospholipids


Phosphorus (food source)



Phosphorus: Toxicity and Deficiency

-Concern if pre-existing kidney disease
Kidney excrete it

-Rare- most people easily meet their needs


Soda Consumption Linked to Reduced Bone Mass

-Soda contains phosphoric acid
*Sharp tart flavor
*Slows growth of mold and bacteria
-Theories (why soda is detrimental to bone health)
*Acid leaches calcium from the bones
*Caffeine causes calcium depletion in urine- younger people compensate with increased absorption, elderly with high intake do not
-Probable Cause: Soda – Milk displacement effect



-Enhances tooth mineralization
*Fluoride + calcium + phosphorus → fluorohydroxyapatite
-Inhibits acid producing bacteria
-Stimulates new bone growth- Tx for osteoporosis?


Flouride (Source, Deficiency, Toxicity)

-Fluoridated water
-Fluoride-containing toothpaste/mouthwash

-Dental caries

-Fluorosis: white to dark stains



-Major mineral
*Makes up bone structure & regulates formation of bone crystals
*Cofactor for >300 enzymes
*DNA and protein synthesis and repair
*Supports vitamin D metabolism, muscle contraction & blood clotting


Magnesium (food sources)

-Green leafy vegetables
-Whole grains
-Seeds, nuts
-Some dairy


Magnesium (Deficiency&Toxicity)

-No disease
-Symptoms are diarrhea, nausea, cramping

-Cramps, spasms, seizures, nausea, weakness
-Associated w/ osteoporosis, heart disease, high blood pressure, type 2 diabetes


Vitamin K

-Fat soluble vitamin responsible for the production of proteins for
*Blood clotting
*Bones- high K, low fractures


Vitamin K (sources)

-Found in green leafy vegetables: kale, spinach, collard greens, turnip grns
-Made in the gut


Vitamin K (deficiency&toxicity)

-Rare, but fatal resulting in severe bleeding

Risk of Deficiency:
-Diseases with fat malabsorption (GI diseases)
Newborns: in US receive vitamin K (no stores, bacteria)

-Toxicity : none


Micronutrients Involved with Blood Health

-Blood transports to the cells
all the components necessary for life!
-Removes waste generated from metabolism.

Iron, Zinc, Copper, Vitamin K, Folate, Vitamin B12


Iron: Functions

Major functions:
-Oxygen transport, part of
*Hemoglobin: Transports oxygen to cells
*Myoglobin: Transports and stores oxygen with in muscles
-Plays several roles in energy metabolism (part of proteins in TCA & ETC)


Iron In The Body

-Iron homeostasis is important
*Insufficient = anemia
*Excess iron = oxidative and can damage tissues
-Iron homeostasis is maintained by means of regulating
*Absorption: absorb more in times of need
*Storage: stored in enterocyte and liver cells for future needs
~largely recycled, recycling provides 20x more iron to the body than the diet
~lost via GI cell turn-over, blood loss


Iron Homeostasis: Absorption

-↑ absorption in times of deficiency: normal 14% abs. ↑ to 40%
-↓intake , ↑absorption
-Amount of stomach acid → ferrous Fe2+ (who is at risk?)
-Heme (Fe2+) vs non-heme sources
-Presence of dietary factors with non-heme
*Enhance: Vitamin C, meat protein factor (MPF)
*Inhibit: phytates, polyphenols (oregano, tea, coffee, red wine), vegetable proteins (soy), fiber and calcium
*RDA assumes 18% absorption, but vegetarian ~10% thus higher RDA


Iron In The Diet: RDA

-8 mg/day for men 19- >70 (14 mg/day for vegetarians)
-18 mg/day for women 19-50, (32 mg/day for vegetarians)
-27 mg/day for pregnant women
-9 mg/day for lactating
-Higher in 14-18 y.o. too

Why is the RDA so varied?
-Vegetarians: poor absorption
-Women: menstruation
-Pregnancy: increased BV, fetal needs
-Lactating: lack of menstruation


Iron In The Diet: Sources

Iron is found in animal & plant sources
*Found in animal protein as part of hemoglobin & myoglobin
*more absorbable form

*Found in plants & animals: legumes, whole grains, some vegetables
*Iron skillets: tomato sauce glass pan 0.6 vs iron pan 5.7 mg
*acid enhances absorption


Iron Toxicity

-Accidental overdose (acute)
*Most common cause of poisoning deaths in children
*Damage intestinal lining, changes in pH, liver failure
-Iron overload (chronic)
*Over consumption of supplements/food
~Prooxidative: damage LDL, insulin resistance & cancer
~UL 45 mg/day from all sources


Iron Deficiency

-#1 micronutrient deficiency worldwide: ~80% of the World’s population have low stores, 30% anemic
*Considered 1 of the top 10 greatest health risks worldwide

-Anemia: ↓ oxygen-carrying capacity of the blood
*reduced ability to produce energy
*body can’t make RBC
*tired, poor performance --> income, communities, nations
*impaired immune function--> increased healthcare $
*Children: premature birth, LBW, infections, premature death, impaired mental and physical development, behavioral problems


Iron Deficiency (causes)

-Causes: poor intake, poor absorption, increased needs, increased blood loss
-At risk groups
*Low income, vegetarians, toddlers, women, pregnant women, adolescents (boys & girls), elderly, athletes
*25% of adolescent girls & women consume RDA
*Animal flesh at each meal, cast-iron pans, vitamin C w/meals
*Avoid iron-rich foods with milk, zinc or calcium supplements
*Anemia= supplemental doses to reverse


Folate: B-Vitamin

Highlight functions:
-Red blood cell synthesis
-Cell division & neural tube formation

-Neural tube defects(spine bifia): increased RDA for pregnancy
*Grain supply is fortified to prevent

-Folate food sources: fortified grains, green leafy vegetables (foliage)
-Folic acid: supplements & fortification, more bioavailable


Folate: Toxicity

Toxicity from supplements:
-Two studies have found folate supplements (with other b-vitamins) in people that have had a heart attack, can increase the risk of death


Vitamin B12

Highlight function: RBC synthesis, neurological function

Sources: animal foods, meat more than milk, fortified foods

Storage: humans have ~3-6 yr storage if completely removed from the diet, longer if some consumed

Absorption: HCL & intrinsic factor are needed

Deficiency: Macrocytic anemia, reduced cognition/dementia

At risk groups: vegans & lacto-ovo veg, elderly w/ atrophic gastritis & ↓ IF production ; 1.5-15% general pop deficient, higher in at risk groups

Management: >50 y.o. obtain mostly from fortified foods or supplements; injections



-Trace mineral found in muscles & bone
-No storage sites in the body
*Maintains protein structure with zinc fingers
~Allows for protein receptor binding & gene expression
*100+ enzymes need zinc to function
~Superoxide dismutase: antioxidant enzyme
~Enzymes for DNA synthesis
*Regulates cell signaling & hormone activity
*Needed for normal growth & sexual maturation


Does Zinc Cure the Common Cold?

-Zinc administered within 24 hours of onset of symptoms reduces the duration of common cold symptoms in healthy people.
-As the zinc lozenges formulation has been widely studied and there is a significant reduction in the duration of cold at a dose of ≥ 75 mg/day, for those considering using zinc it would be best to use it at this dose throughout the cold.
-When using zinc lozenges (not as syrup or tablets) the likely benefit has to be balanced against side effects, notably a bad taste and nausea


Zinc (RDA&Food Sources)

-11 mg for men
-8 mg for women

Food Sources:
-Oysters (6 oysters >RDA)
-Fortified cereals
-Beef, crab


Zinc (Toxicity&Deficieny)

-Not from food
-↑↑ supplemental use can: ↓ iron absorption

-Rare in US
-Growth retardation, delayed sexual maturity, infections