Nutrition And Bone Health Flashcards
Serum calcium levels are increased by what
Decreased calcitonin and increase PTH
What vitamin deficiency causes osteomalacia/ rickets
Vitamin D deficiency caused by
Decrease dietary intake
Decreased exposure to sunlight
Impaired absorption by intestines and kidneys
what is the effect on calcium levels during pregnancy
Calcium absorption is doubled during pregnancy
Increased estrogen levels cause increased osteoblast activity and bone resorption
Skeletal calcium is the predominant source of calcium in breast milk.
Female athlete triad
Amenorrhea
Osteoporosis
Disordered eating
Causes impaired bone mass
Carbonated soft drinks are associated with what?
Lower bone density
Peak bone mass is a product of what
genetics and lifestyle factors
Primarily genetics though.
PTH
Increases osteoclast activity
Increases vitamin D activation and decreases Ca excretion via urine.
Estrogen and testosterone increase osteoclast or osteoblast activity?
Osteoblast
Lactation causes what the bone mass?
Decreases bone mass since the majority of calcium in breast milk comes from skeletal calcium
Increase in total body fat causes what to bone mass?
Decreases it.
Total body fat has an inverse relationship to bone density/mass
What lifestyle factors have strong evidence supporting a direct effect on peak bone mass
Calcium intake
Vitamin D intake
Dairy intake
DMPA shots (negative effect on bone mass)
Physical activity and exercise
Rule of 300 for calcium
Quick rough way to determine the estimated calcium intake someone is having
estimated # of servings of dairy a day x300
add another 300 if its a well balanced diet
Ex: 4 servings of dairy in a well balanced diet = approx. 1500 mg/day of calcium
How much dietary Ca2+ is absorbed?
Less than 50%
49% of kidney reabsorption of calcium is controlled by what?
PTH
99% of filtered blood calcium is reabsorbed by kidneys
What types of vegetables contain very little bio-available Calcium?
High oxalate vegetables
Oxalate is known to impair calcium absorption.
What two nutrients directly affect calcium requirements?
Sodium and protein
When sodium and protein concentrations are low, so is calcium intake requirement
however low protein can stimulate PTH hormone due to decreased instance calcium absorption, which would result in bone loss
Vitamin D effect on calcium
Essential for intestinal absorption of calcium
Helps also maintain serum calcium and phosphate levels.
Enables normal bone mineralization and prevents hypocalcemia tetany.
RDA for vitamin D with respect to age groups
0-12 months = 400 IU
1-70 yrs = 600 IU
71+ = 800 IU
Groups @ risk for Vit. D deficiency
Breastfed infants
Older adults
Limited sun exposure
Inflammatory bowel diseases
Obese populations or people who have undergone bypass surgery.
Vitamin A deficiency and excess affect on bone
- only affects through supplements*
Deficiency can lead to osteomalacia type symptoms
Excess can lead to hypercalcemia
Magnesium affects on bone
Involved directly with osteoblast and clast balancing
Deficiency leads to osteoporosis and bone stiffness due to over abundance of hydroxyapatite crystals.
Deficiency also hyper-stimulates osteoclasts and blasts
Should never take magnesium and calcium supplements together. Has shown to decrease calcium absorption
Vitamin K effects on bone
Involved in carboxylation of osteocalcin.
Ultimately inhibits osteoclastgenesis and promotes osteoblast genesis
Deficiencies cause increased fracture risk and osteoporosis.
Vitamin C effects on bones
Cofactor for hydroxylation of lysine and proline during collagen synthesis
Helps generate cartilage, which some is used for Endochondral ossification of bone.
Daily recommendations = 400mg
Fluoride effect on bone
Unknown however is hypothesized to stimulate osteoblasts but can contribute to bone fragility if too high.
Supplementation is not approved
Caffeine affect with bone
Small effect on decreased calcium absorption
Overall not really an effect
