MSK Nutrition Flashcards
What are the major minerals that are needed for the skeleton?
Na
Ca
P
Mg
K
Bone is 20-40% […] and 50 - 70% […]
Organic
Inorganic
The organic part of bones is made of up what 3 coponents?
- Collagen
- Proteoglycans
- Glycoproteins
Adequate […] and […] are needed to maintain collagen
Protein
Vitamin C
Other than hydroxyapatite, what 4 components are present in the inorganic phase of bone?
Carbonate, magnesium, sodium, fluoride
How is calcium absorbed?
Via active transport and passive diffusion depending on availability of 1,25 Dihydroxyvitamin D
The inorganic phase of bone provides […]
Strength
When is Ca2+ absorbed passively?
When concentrations of calcium are high in the lumen of the small intestine
When is Ca2+ absorbed actively?
Low to moderate concentrations of calcium require active transport and require vitamin D for transport. Vitamin D promotes the transcription of genes for calcium transport protein, which shuttles calcium across mucosal cells. Calcium is then actively transported across the apical side of the mucosal cell into the bloodstream.
Describe the regulation of calcium when blood calcium is high.
High blood calcium leads to the release of calcitonin from the thyroid gland, which inhibits the release of calcium from the bones and promotes calcium deposition in the bones.
Describe the regulation of calcium when blood calcium is low.
Low blood calcium causes the release of PTH from the parathyroid gland which promotes calcium reabsorption in the kidneys, calcium absorption in the intestines and release of calcium from the bones.
Do children and teens need more or less calcium in their diet than adults?
More - RDA is 1300 mg
What is RDA for calcium for adults?
1000 mg
What is the RDA for adult women 51+?
1200mg
What is the RDA for calcium for pregnant and breastfeeding teens?
What about pregnant and breastfeeding adults?
1300mg
1000mg
What are good sources of calcium in the diet?
- Canned sardines
- Canned salmon
- Milk
- Yogurt
- Cheese
- Kale
- Broccoli
- Tofu
[…] products provide 72% of total calcium intake and are the leading sources of calcium intake among children.
Dairy
What factors affect calcium bioavailability?
- Vitamin D –> increase absorption
- Vitamin C –> increase absorption
- Acidic pH –> increase absorption
- Increasing age –> decreasing absorption
- Amount consumed - no more than 500mg can be absorbed at one time
- A diet high in phytic and oxalic acids –> decrease absorption
How does a high sodium diet affect calcium absorption?
It leads to Ca loss, but only a problem when Na intake is really high and Ca intake is low
How does alcohol use affect Ca absorption?
Reduces Ca absorption and intereferes with metabolism of vitaminD in the liver
How does caffeine consumption affect Ca absorption?
There is a small decrease in absorption due to the increase in excretion (caffeine is a mild diuretic). Can be combated by adding cream or milk to coffee.
What are the health risks of being calcium deficient?
Osteoporosis
Osteomalacia
Rickets
Peak bone mass not achieved
Fragility fractures
Impaired muscle contraction
What are the health risks of excess calcium?
Vascular and soft tissue calcification
Hypercalcuria
Kidney stones
GI distress
Altered trace mineral absorption
Who are the most at risk of calcium deficiency?
- Postmenopausal women
- Children and adolescents
- Men older than 70 years of age
- Amenorrheic women
- Individuals with lactose intolerance
- Vegetarian or vegan individuals
What are the recommendations for calcium supplementation?
Recommended from food first and supplement only if unable to meet calcium requirements from food
Calcium carbonate needs […] to absorb, and is best taken with […].
Acid
Food
Calcium citrate doesn’t require […] to dissolve and may be taken with or without […]
Acid
Food
What are sources of vitamin D in the diet?
Liver, fatty fish, fish oils, egg yolks
What are the main reasons for low vitamin D?
- Lack of VitD in diet
- Inadequate sun exposure
- Decreased capacity to synthesize vitD with age
- Inability to process vitD to active form due to kidney or liver disease
Why is phosphorous deficiency rare?
Because food in the western diet is highly fortified with phosphorous
