Ch 9: Nutrients involved in bone health Flashcards
What makes up the structure of bone
65% minerals -providing hardness
35% orgainic structures for strength, durability and flexibility
Collagen- fibrous pro in bone
What are the metabolic processes associated with bone + what does it store(3)
- Acts as storage reseviour for minerals such as calcium, phosphorus and fluoride
- bone marrow produces new blood cells
When is bone growth completed in males and females
14 in girls
17 in boys
What is the most accurate way to to assess bone density and who is it recommended for
DEXA scan
-recommended for post menopausal women mainly
Where is most calcium found in the body
99% found in bone
1% remaining is found in blood/soft tissues
What occurs when there is low calcium levels
Parathyroid horomone release which stims activation of Vit D
What does PTH and vit D cause
- kidneys to retain more calcium
- osteoclasts to break down bone to release calc
- stims calc absorption in intestines
What occurs when there is high calcium levels
thryroid releases calcitonin
Cacitonin functions to:
- prevent calcium reabsorbtion
- limit absorption in intestines
- inhibit osteoclast breakdown
bioavailibity of calcium in children, preg women, adults, older adults
children- 60%
preg- 50%
adults-30%
older- 25%
max absorbed amount of calcium @ one time
500mg
what occurs when you consume too much calcium and what can it be caused by
Hypercalcemia can be caused by cancer + overprod of PTH
-calcium supplementation can compete with absorption of iron/zinc/magnesium
What can low blood calcium be due to
can be caused by kidney diease or overproduction of PTH
What is vitamin d technically
technically a horomone as it is synthesized in one location and acts upon another
-synthesized by UV light
Functions of Vit D
- Regulates blood calc
- Required for calc + phosphorus absorption
- Stims osteoclasts
- Necessary for calcification of bone
RDA for adults + ind over 70
15ug day
20ug day over 70
Why does overconsumpton of Vit D happen and what does it cause
occurs from vit supplements (not excessive exposure)
-results in hypercalcemia
What happends if you dont consume enouch vit D (2) and what causes it
-Occurs w diseases that reduce intestinal absorbtion of fat/limited sun exposure
Rickets- inadequate minerization in nine
Osteomalacia- loss of bone mass in adults
What is the plant form and large intestine form of Vit K
plant form- Phylooquinone
Intestine by bacteria- Menaquinone
Function of vit K (2) + RDA
- Blood coagulation
- Bone metabolism
RDA- no RDA for vit K
What happens if you overconsume/underconsume vit K
too much- no side effects
too little- reduced blood clotting/excessive bleeding
occurs w diseases that limit absorption of fat
Function of Phosphorus and RDA
- Critical to mineral composotion of bone
- required for proper fluid balance
- component of ATP, DNA, membranes
RDA= 700mg/day
What occurs in excess phosphorus consumption and why does it happen
Excesive vit D sups or consumption of too many phosphus containing antacids
-mm spasms, convulsions
Where is most magnesium found and functions
50-60% found in bone
- mineral found in bone structure
- cofactor for over 300 enzyme systems
- required for production of ATP, DNA, Pros
RDA of magnesium
310-420mg/day
