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Bone Health (bone (characteristics (strong), composition (~35 organic…

- - - - flexible
  - - - ivory-like, dense, strong, slow turnover
      - ~80% of skeleton
      - small bones
    - - lace-like, not dense as cortical, very dynamic, sensitive to hormones that regular blood calcium
      - ~20% of skeleton
      - ends of long bones
      - spinal vertebrae
      - inside flat bones
      - pelvis bone
- - - - ex: rib cage
- - - - non-invasive, painless, relatively quick
      - very low x-ray energy scan
      - scans entire body or specific areas
    - - non-invasive, painless
      - sound waves
      - no diagnostic use
      - often use the heel
    - - x-rays measure bone density in heel, wrist, finger
      - non-invasive, painless
      - no diagnostic use
- - - - calcitonin
        
        inhibits the activation of vitamin D
        
        prevents calcium re-absorption in kidneys
        
        limits calcium absorption in the intestines
        
        inhibits osteoclast cells from breaking down bone, preventing the release of calcium
      - when blood calcium levels are lowered, the secretion of calcitonin is inhibited
  - - - parathyroid stimulates the activation of vitamin D
        
        vitamin D and parathyroid
        
        stimulate calcium reabsorption in kidneys
        
        stimulate osteoclast cells to break down bone, releasing calcium into blood
        
        Vitamin D
        
        enhances calcium absorption in the intestines
        
        when blood calcium levels are raised, the secretion of parathormone is inhibited
- - - - Crystals deposited onto the PRO collagen matrix of bone
        
        Provides strength and rigidity to bones
      - Substitutions for the hydroxyapatite crystals include:
        
        Sodium ion for calcium ion
        
        Potassium ion for calcium ion
        
        Strontium ion for calcium ion
        
        Carbonate for phosphate salts
        
        Magnesium ion for calcium ion
        
        Hydrogen phosphate for phosphate salts
        
        Flouride for hydroxide
  - - - Phospholipids in cell membrane and lipoproteins to transport fat-soluble nutrients in the body
      - Many enzyme reactions — many B-vitamins become active when a phosphate group is added
      - Very high energy phosphate bonds (e.g. ATP)
      - Essential for growth in DNA & RNA
    - - Acts as a buffer
- - - - prothrombin uses calcium and thromboplastin from blood platelets to form thrombin
        
        thrombin is used to transform fibrinogen to fibrin
  - - - Estrogen increases active vitamin D synthesis
        
        Increasing calcium absorption
      - Absorption is proportional to needs:
        
        ~50% is absorbed in pregnant women
        
        ~50% is absorbed to meet growth needs
      - Absorption depends on active vitamin D present in
        
        Intestinal cells
      - Younger people absorb more
      - Majority absorbed in duodenum
        
        Transiently acidic when absorbed, leading to
        
        Increased solubility
      - Lactose increases calcium absorption
    - - Food Constituents
        
        Certain acids that decrease absorption include
        
        Phytic acid in whole grains and legumes
        
        Oxalic acid in vegetables
        
        High fat intake can lead to
        
        Steatorrhea, which is
        
        Fat found in stools
        
        For high fibre diets: ~50+ g/day
        
        vitamin D deficiency
        
        Polyphenols lead to decreased absorption
        
        Polyphenols such as tea and coffee
      - Supplement Use
        
        Appropriate supplement use would be
        
        High magnesium, phosphorus, zinc, or iron takes along with low calcium intakes
        
        % absorbed is lower the more to intake
        
        Therefore take calcium supplements <= 500mg/dose
      - Old Age
        
        Decreased stomach acidity
        
        Decreased efficiency of absorption
      - Menopause
        
        End of menstrual cycle
        
        Lowering of estrogen levels
  - - - Hydroxyapatite crystals
        
        Found in protein collagen matrix of bone where it
        
        Provides strength and rigidity
  - - - Ion flow in nerve cells release of
        
        Neurotransmitters
        
        Allow nerve cells to communicate
      - Sodium-Potassium ATPase pump allow flow of
        
        Sodium and potassium ions across membrane to generate action potential
        
        Action potential travels down nerve fibre to interact with muscle cell
        
        Calcium flows out, causing muscle relaxation
        
        Calcium flows in, causing muscle contraction
      - Low cellular calcium levels cause TETANY
        
        Spasmodic relaxation
      - High cellular calcium levels cause RIGOUR
        
        Muscles cannot relax after contraction
    - - Calcium essential in blood clotting process
        
        Helps lead to formation of fibrin and a clot
  - - - Hypercalcemia
        
        High levels of calcium found in blood and urine
        
        Calcium deposits into soft tissue
        
        Can cause irreversible damage to organs
    - - Those with kidney disease
    - - Hyperparathyroidism
        
        Over-abundant production and secretion of parathyroid hormones
        
        Retain calcium in blood and bone to release calcium into blood
  - - - Effects of osteoporosis can be reduced by
        
        Building peak bone mass early in life (teen and early adult years)
      - Cannot rely on blood calcium levels to warn us our calcium levels are low
      - Is a pediatric disease that does not manifest itself until of old age
      - Multifactorial disease
      - Naturally occurring degenerative bone disease
        
        Characterized by
        
        Increased bone fragility
        
        Increased risk of fractures, especially in the hip, spine, and/or wrist
        
        Decreased bone density
      - Genetics play a large role in your profile for osteoporosis
      - Can Bone Loss be Prevented?
        
        We want to reduce the rate at which
        
        Bone is lost as much as possible
        
        Bone loss is natural in aging
        
        Consult with a health care provider to see which therapy would work best:
        
        Calcitonin Therapy
        
        Nasal spray called miacalcin available in Canada for the therapy
        
        Hormone in pituitary gland released inhibits loss of minerals from bone
        
        Decreasing action of osteoclasts
        
        Vitamin D Therapy
        
        Active vitamin D administration causes
        
        Calcium has increased absorption at intestinal cells
        
        Increased retention of calcium at the kidneys
        
        Estrogen Therapy
        
        If stopped, rate of bone loss will increase then taper off
        
        Increases risk of breast or endometrial cancer
        
        Slows rate of bone loss
        
        Estrogen + ~1500mg calcium per day
        
        Used at menopause to compensate for loss of estrogen
        
        Biphosphonate Therapy
        
        There are side effects and the cost is expensive
        
        Medication targets inhibiting osteoclasts activity
      - 1 in every 4 Canadian women and 1 in every 8 Canadian men over the age of 50 develop osteoporosis
      - Factors that affect the risk of developing osteoporosis
        
        Genetics/Race
        
        African Americans have more dense bones than Caucasian Americans
        
        Heredity plays a role in bone growth, PBM, and rate of bone loss
        
        Physical Acitivity
        
        Weight-bearing exercise leads to
        
        Increased muscle and bone strength
        
        And muscles pull on bone
        
        Increasing strength of trabecular bone
        
        Hormones involved in muscle growth are also involved in bone growth
        
        Without activity, you lose bone
        
        Body Weight
        
        Underweight women have increased risk of osteoporosis
        
        Smoking and Alcohol
        
        Smokers have lower body weights
        
        Increasing risk of osteoporosis
        
        Female smokers reach menopause earlier than non-smokers
        
        Hastens estrogen breakdown
        
        Alcoholics have slower bone formation
        
        Alcohol is also toxic to bones
        
        Calcium Nutrition and Associated Nutrients
        
        Calcium supplements (that contain vitamin D) for people not consuming milk or milk products
        
        Recommended about ~1g Calcium/day divided into 500mg doses
        
        Excess sodium, caffeine, or protein
        
        Causes urine lost in the urine
        
        Only a concern if person suffering from low calcium intake
        
        1 cup of coffee -> loss of 2-3mg of calcium
        
        1g of protein over the RDA -> loss of ~1-2mg calcium
        
        1 more item...
        
        2g sodium -> loss of ~40mg calcium
        
        Fluoride intake during youth can increase bone crystal strength
        
        Deficiency in Calcium will cause overall calcium absorption to decrease
        
        Vitamin D deficiency causes decreased Calcium absorption
        
        Age/Gender/Hormones
        
        Men
        
        Have greater bone density than women at maturity
        
        Therefore less chance of osteoporosis
        
        Gradual decline in testosterone
        
        Have increased incidence of fractures that come along with disease to
        
        Testes or aging
        
        Slow bone loss occurs at age of ~30
        
        Men don’t live as long as women
        
        Dieting and exercise after adolescence can compromise osteoporosis
        
        Strongest at young age
        
        Girls experience pressure to be thin at an age where bone density matters
        
        Max bone mass occurs during teen
        
        Continues until 25-30 if there exists adequate calcium intake and other nutrients
        
        Nutrients like phosphorus, magnesium, zinc, and flouride
        
        Called Peak Bone Mass (PBM)
        
        Different bones reach max bone mass at different ages
        
        Osteoblasts become less active as osteoclasts stay the same
        
        Osteoblasts build bones whereas osteoclasts breakdown bones
        
        Women ~40 years under menopause phase have lowered bone loss rate and continuous
        
        At menopause, bone loss accelerated for 5-10 years
      - Factors Associated with Reducing the Potential for Fractures
        
        Adult women and men
        
        Moderate active lifestyle, weight-bearing activities
        
        If smoking, quit smoking
        
        Smoking lowers estrogen levels which increases bone loss
        
        Adequate intake of nutrients support bone health
        
        Moderate alcohol consumption or none at all
        
        Alcohol is toxic to bone
        
        Women and menopause
        
        Appropriate therapy reduces potential of fractures
        
        Remain physically active
        
        Adequate intake of nutrients support bone health
        
        Make healthy lifestyle choices
        
        Some sun exposure
        
        Young women
        
        Limit exposure to sun
        
        Limits uptake of vitamin D
        
        Regulates calcium-binding protein activity in the intestinal cells
        
        Moderate active lifestyle, weight-bearing activities
        
        Regular menstruation and ovulation
        
        Adequate calcium during growth, as well as
  - - - Males and females
        
        9 - 18 years old
        
        RDA: 1300mg/day
        
        19 - 50 years old
        
        RDA: 1000mg/day
    - - Males and females
        
        71+ years old
        
        RDA: 1200mg/day
      - Males
        
        51 - 70 years old
        
        RDA: 1000mg/day
      - Females
        
        51 - 70 years old
        
        RDA: 1200/mg/day
    - - Men ~930mg/day
      - Women ~800mg/day
  - - - Absorption is about 30% for all supplements
        
        Take calcium carbonate with food
        
        Calcium citrate can be taken without food
      - Take at low calcium or iron intake
    - - Take in divided doses during the day
        
        Max 500mg calcium/dose
    - - Different amounts of calcium in each supplement and different bioavailability per type
      - Avoid
        
        Unrefined supplements that contain heavy metals such as lead mercy, or cadmium
        
        Unrefined oyster shell, dolomite, coral, or bone meal supplements specifically
      - Common tables include
        
        Citrate
        
        Phosphate
        
        Carbonate
        
        Lactate
      - UL for calcium is 2500mg/day
      - Tablets, chewables, liquid, effervescent
      - Intakes greater than UL, may lead to increased blood calcium and loss of calcium in urine
        
        As well as
        
        Kidney stone
        
        Kidney failure
        
        Soft tissue calcification
        
        Decreased absorption of other minerals
    - - Take at low calcium or iron intake
      - Decreases absorption of other minerals
      - Take before bed
      - Take everyday for adequate calcium intake
        
        Keep container out of children’s reach
  - - - Cheese
      - Calcium-fortified orange juice
      - Yogourt
      - Tofu
      - Calcium-fortified bars
    - - Oxalic acid decreases the bioavailability
    - - 5 tbsp of skim milk is equivalent to 1 cup of milk
    - - !300mg/cup @ 86kcal/cup
    - - Fortified soy and other plant based beverages
    - - 1 tbsp may contain more than 100mg of calcium
- - - - bone acts as a storage of Magnesium in the body
      - Magnesium helps prevent dental caries by holding calcium in the enamel
      - Magnesium needed for the mineral crystal structure in bone
        
        can replace calcium in hydroxyapatite
      - Effect on calcium balance because Magnesium is needed for the action of calcium regulating hormones
    - - Enzyme systems
      - Nerve transmission and muscle contraction activity
      - Stabilizes phosphate groups in ATP
      - Blood clotting
        
        Magnesium inhibits it
    - - protects against hypertension and heart disease
      - Lowers rates of heart disease are observed when there is a harder access to water
  - - - Irregular heart beat
      - loss of appetite
      - tetany at extremely low levels of Magnesium in the body
  - - - 19-30 yr: 400 mg/day
      - 31+ yr/ 420 mg/day
    - - 31 yr +/ 320 mg. day
      - 19-30yr/ 310 mg/day
  - - - Whole grains, nuts, seeds, tofu
- - - - Distance from equator
      - Pollution
      - Age
      - SPF>=8
      - Skin colour
      - During what time of day is person exposed
    - - Required to have dietary intake of vitamin D
    - - Hydroxylation of vitamin D3 in liver and again in kidney
        
        Fully activates Calcitriol (active vitamin D)
  - - - Activated in kidneys and liver to form active calcitriol
  - - - calcitriol associated with maturation of immune cells
    - - kidneys
      - bone
      - intestines
    - - calcitriol increases calcium blood levels
      - other hormones involved in regulating blood calcium too
  - - - needed for the nervous system
      - Possible role in multiple sclerosis
        
        T2D
        
        T1D
      - needed for skin
      - needed for muscles
      - needed for reproduction
    - - Calcitriol associated with maturation of immune cells
    - - acts on the following to increase reabsorption and retention of calcium in the body
        
        bone
        
        kidneys
        
        intestine
  - - - Osteomalacia "soft bones" disease
        
        progressive weakness with increasing pain in lower back and legs causes
        
        low intakes of vitamin D and less exposure to the sunlight
        
        closely spaced, repeated pregnancies
        
        a treatment to this would be:
        
        increased exposure of skin to the sunlight
        
        increased dietary intake of vitamin D
        
        kidney, liver, and intestinal diseases
        
        decreases the absorption of vitamin D
        
        inefficient conversion to active form (calcitriol) in the liver and/or kidneys
        
        osteoid
        
        is a protein matrix secreted by osteoblasts
        
        minerals deposited to form bones
        
        In Osteomalacia, osteoid doesn't mineralize properly and accumulates, making bones soft and less rigid
    - - Rickets disease
        
        breastmilk carries low vitamin D
        
        prevalence increasing in Canada
        
        infants born with about 9 months worth of stores depending on the maternal diet
        
        poor mineralization and bone formation, bowed legs, malformed ribs due to inadequate dietary intake of vitamin D
      - children at risk if
        
        little exposure to the sun
        
        dietary intake of vitamin D is low
  - - - solar exposure
        
        non-toxic
      - food intake
        
        safe, non-toxic
      - supplement use
        
        most likely reason for toxicity
    - - High blood calcium levels
        
        calcium deposits into soft tissue
        
        may cause irreversible damage to organs
  - - - animal foods:
        
        egg yolk
        
        liver
        
        fish and fish oils
    - - orange juice
      - yogourt
      - margarine
      - fortified milk
  - - - adults over 50 recommended to take additional 400 IU of vitamin D daily
    - - fat-soluble
      - taking high doses can calcify and damage soft tissue
      - 50-80% of ingested amount
      - fish oil supplements high in vitamin D and A
        
        use with caution
    - - liquids, tablets, softgels
      - vitamin D2 or D3 supplements
        
        both absorbed but D3 more biologically effective in the body
  - - - usual intakes that are adequate
        
        Canadian men: ~6 µg/day
        
        Canadian women: ~5 µg/day
      - 1 µg active calcitriol = 40 IU
      - assumes no solar synthesis
    - - all adults:
        
        100 µg/d (4000 IU)
- - - - menaquinone (animal)
      - 40-80% absorbed
      - stored mostly in liver, some in adipose tissue
      - coenzyme for protein synthesis
      - antibiotic use can increase dietary need
      - phylloquinone (plant)
  - - - needed for osteoblasts to produce osteocalcin
        
        a calcium binding hormone made in osteoblasts that promotes calcium mineralization
    - - especially important who are bone with a sterile gut
        
        no bacterial synthesis
        
        infants receive a dose of vitamin K shortly after birth to prevent hemorrhaging
      - takes a few weeks to establish bacterial synthesis of vitamin K
      - fibrin clot consists of 13 proteins
        
        4 of which require vitamin K for synthesis
  - - - infants
        
        no vitamin K synthesis at birth (sterile gut)
        
        low levels in breast milk
        
        low levels of gut bacteria after a few weeks
      - adults
        
        rare
        
        usually due to antibiotic use
        
        people with fat malabsorption conditions
        
        ex: Crohn's, Cystic Fibrosis, AIDS
        
        excessive intakes of vitamin E can impair the role of vitamin K in blood clotting
  - - - wide safety intake range
    - - RBC hemolysis
      - jaundice
      - brain damage
  - - - adult males: 120μg/day
      - adult females: 90μg/day
    - - none for both genders
  - - - leafy green vegetables
        
        ex: broccoli, spinach, kale, brussel sprouts
      - cauliflower
      - avocado
      - cabbage
      - liver
      - eggs
      - milk (cow)
    - - bacterial synthesis in large intestine
    - - resistant to losses during cooking