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Nutitional Science > Micronutrients involved in Bones and Blood > Flashcards

Micronutrients involved in Bones and Blood Flashcards

1
Q

Why Are Bones Important?

A
  • 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

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2
Q

Bone Composition

A
  • 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
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3
Q

Bone Development

A

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
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4
Q

Bone Growth

A
  • Determines bone size
  • Begins in the womb
  • Continues until early adulthood
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5
Q

Bone Modeling

A
  • Determines the bone shape
  • Begins in the womb
  • Continues until early adulthood
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6
Q

Bone Remodeling

A
  • Maintains integrity of bone
  • Replaces old bone with new bone to maintain mineral balance
  • involves bone resorption and formation
  • occurs predominately during adulthood
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7
Q

Cells Involved in Bone Remodeling

A
  • Osteoclasts: dissolve bone, resorption, “crushing”
  • Osteoblasts: bone “building” cells
  • Osteocytes: fully matured osteoblasts, bone cells
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8
Q

Phases of Bone Development Throughout Life

A

-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

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9
Q

Calcium

A

-Most abundant mineral in our body

Functions:

  • provide structure to bones and teeth
  • acid-base balance (Ca basic)
  • transmission of nerve impulse
  • muscle contraction
  • regulation of hormones & enzymes
  • blood clotting
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10
Q

Calcium Absorption

A
  • 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)
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11
Q

Blood Levels of Calcium Are Tightly Regulated

A

Think for a minute, how might our bodies regulate calcium?

  • Storage: bones
  • Excretion: kidneys
  • Absorption: GI
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12
Q

RDA & Food Sources for Calcium

A
  • 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.
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13
Q

Calcium Toxicity

A

-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

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14
Q

Calcium Deficiency

A
  • ↓ 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
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15
Q

Factors Affecting Risk of Osteoporosis

A

-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
-Amenorrhea
-Exercise
-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

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16
Q

Management & Prevention

A

No cure for osteoporosis but drugs can slow or reverse somebone loss

Prevention by maximizing peak bone mass before early adulthood

  • Optimal calcium & vitamin D
  • Active lifestyle: weight bearing exercise- strength training, running, stair climbing
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17
Q

Vitamin D

A

-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
-Functions
*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

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18
Q

RDA: Vitamin D

A
  • 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
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19
Q

Vitamin D & Food

A
  • 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
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20
Q

Sunlight & Vitamin D

A

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

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21
Q

Vitamin D: Toxicity

A

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

  • ↑ blood calcium levels
  • Calcium deposits in heart, liver, kidney
  • Can be fatal
22
Q

Vitamin D: Deficiency

A
  • Rickets
    • Children
    • Inadequate mineralization, soft bones
    • Bowed legs
  • Osteomalacia
    • Adults
  • Osteoporosis
23
Q

Risk of Vitamin D Deficiency

A

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)
24
Q

Phosphorus

A

Functions
-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
25
Q

Phosphorus (food source)

A
  • Milk
  • Meat
  • Beans
  • Grains
26
Q

Phosphorus: Toxicity and Deficiency

A

Toxicity:
-Concern if pre-existing kidney disease
Kidney excrete it

Deficiency:
-Rare- most people easily meet their needs

27
Q

Soda Consumption Linked to Reduced Bone Mass

A
  • 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
28
Q

Fluoride

A

Functions:

  • Enhances tooth mineralization
    • Fluoride + calcium + phosphorus → fluorohydroxyapatite
  • Inhibits acid producing bacteria
  • Stimulates new bone growth- Tx for osteoporosis?
29
Q

Flouride (Source, Deficiency, Toxicity)

A

Sources:

  • Fluoridated water
  • Fluoride-containing toothpaste/mouthwash

Deficiency:
-Dental caries

Toxicity:
-Fluorosis: white to dark stains

30
Q

Magnesium

A
  • Major mineral
  • Functions:
    • 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
31
Q

Magnesium (food sources)

A
  • Green leafy vegetables
  • Whole grains
  • Seeds, nuts
  • Seafood
  • Beans
  • Some dairy
32
Q

Magnesium (Deficiency&Toxicity)

A

Toxicity:

  • No disease
  • Symptoms are diarrhea, nausea, cramping

Deficiency:

  • Cramps, spasms, seizures, nausea, weakness
  • Associated w/ osteoporosis, heart disease, high blood pressure, type 2 diabetes
33
Q

Vitamin K

A

Functions:

  • Fat soluble vitamin responsible for the production of proteins for
    • Blood clotting
    • Bones- high K, low fractures
34
Q

Vitamin K (sources)

A
  • Found in green leafy vegetables: kale, spinach, collard greens, turnip grns
  • Made in the gut
35
Q

Vitamin K (deficiency&toxicity)

A

Deficiency:
-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

36
Q

Micronutrients Involved with Blood Health

A

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

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

37
Q

Iron: Functions

A

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)
38
Q

Iron In The Body

A

-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
*Excretion:
~largely recycled, recycling provides 20x more iron to the body than the diet
~lost via GI cell turn-over, blood loss

39
Q

Iron Homeostasis: Absorption

A
  • ↑ 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
40
Q

Iron In The Diet: RDA

A

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
41
Q

Iron In The Diet: Sources

A

Iron is found in animal & plant sources

  • Heme
    • Found in animal protein as part of hemoglobin & myoglobin
    • more absorbable form
  • Non-heme
    • 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
42
Q

Iron Toxicity

A

-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

43
Q

Iron Deficiency

A
  • # 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
44
Q

Iron Deficiency (causes)

A
  • 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
  • Interventions
    • 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
45
Q

Folate: B-Vitamin

A

Highlight functions:

  • Red blood cell synthesis
  • Cell division & neural tube formation

Deficiency:

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

Sources:

  • Folate food sources: fortified grains, green leafy vegetables (foliage)
  • Folic acid: supplements & fortification, more bioavailable
46
Q

Folate: Toxicity

A

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

47
Q

Vitamin B12

A

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

48
Q

Zinc

A

-Trace mineral found in muscles & bone
-No storage sites in the body
-Functions
*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

49
Q

Does Zinc Cure the Common Cold?

A
  • 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
50
Q

Zinc (RDA&Food Sources)

A

RDA:

  • 11 mg for men
  • 8 mg for women

Food Sources:

  • Oysters (6 oysters >RDA)
  • Fortified cereals
  • Beef, crab
  • Lentils
51
Q

Zinc (Toxicity&Deficieny)

A

Toxicity:

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

Deficiency:

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

Nutitional Science (11 decks)

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