Calcium

Question 1

Explain Calcium

Answer 1

• Most abundant mineral in the body
• 99% in the bones (including teeth)

Question 2

What are the two processes of calcium

Answer 2

• Passive absorbtion
• Active Transport absorption

Question 3

Explain passive absorption

Answer 3

• Depends on vitamin D
• Requires a transporter and energy
• Requires calbindin (calcium binding protein)

Question 4

What is calbindin and what does it need

Answer 4

• calcium-binding protein
• free calcium is very toxic to inside of cells
• need to move calcium across cell
• Need to have calcium BOUND

Question 5

What does calbindin do?

Answer 5

• Binds calcium and acts as a shuttle for calcium through the cell
• facilitates calcium absorption across intestinal cells, also needs magnesium

Question 6

What increases calbindim synthesis

Answer 6

Vitamin D

Question 7

What factors ehnace calcium abrosbance

Answer 7

• Vitamin D
• Presence of calbindin (transport of calcium across intestinal cell)
• stomach acid
• supplememts best absorbed with a meal
• optimal ratio oc calcium to phosphorus

Question 8

What factors Inhibit calcium absorption?

Answer 8

• Vitamin D deficiency
• lack of stomach acid
• excess phosphorus
• high fibre diet
• phytic acid
• oxalate

Question 9

WHat are the two main metabolic roles of calcium

Answer 9

1. bone health
2. regulator of cellular process

Question 10

What is calmodulin?

Answer 10

• intracellular protein/calcium receptors
• aka (calcium-dependent regulatory protein
• found in all cells
• binds intracellular calcium
• allows for signal transduction to occur
• activates proteins and enzymes
• key mechanism of action of numerous peptide hormones

Question 11

Explain how calcium improves bone health

Answer 11

• Bone is a dynamic tissue
• gaining and losing minerals all the time
• The goal is balance
• teeth–> fluoride acts as a stabilizer

Question 12

Explain how calcium is a regulator of cellular processes

Answer 12

• muscle contraction
• transmission of nerve impulses
• membrane excitability
• secondary messenger: signal transduction, intracellular messenger of hormone action
• peptide hormone action:
  1. hormone binds to receptor
  2. now need yo transduce the signal inside the cell
  3. involves G protien that need to be activated
  4. Calmodulin is an intracellular protein (calcium receptor) that binds calcium, allowing for activation of intracellular proteins and enzymes

Question 13

What did the committee say was an indicator of calcium and vitamin D status?

Answer 13

• Bone health

Question 14

Whar are the food sources

Answer 14

• found in very few foods
• content can be increased with more sunlight exposure
• fish, egg yolk, mushrooms, fortified foods- some calcium fortified orange juice

Question 15

What does Health Canada recommends adults >50 years to take?

Answer 15

• supplement of 400 IU (10mcg)

Question 16

Does Canada allow higher vitamin D fortification in milk and margairine

Answer 16

• yes and will eventually become mandatory

Question 17

What are the Minister of Health’s intentions about yogurt and kefir, and vitamin D?

Answer 17

• to publish marketing authorizations to permit vitamin D fortification of yogurt and kefir, and expand the eligibility for dairy-related exemption from the front-of-package nutrition labelling requirement

Question 18

With a vitamin D deficiency what happens to calcium?

Answer 18

• Production of calbindin is decreased
• Calcium absorption is decreased
• thus, vitamin D and calcium are related

Question 19

What are some specific syndromes related to vitamin D and calcium deficiencies?

Answer 19

• Rickets (children)
• osteomalacia (adults)
• osteoporosis (adults)

Question 20

What is rickets

Answer 20

• classic severe vitamin D deficiency disease in children
• also invloves calcium - low blood calcium
• impaires mineralization of growing bones - lumps on ribs due ro unformed bone, growth retardation, skeletal abnormalities, bowlegs, knock knees
• muscle weakness and nervousness

Question 21

What are some factors that could contribute towards the development of rickets

Answer 21

• poor diet
• low UV light exposure:
• pollution
• season
• sunscreen
• tall buildings

Question 22

Expalin osteomalacia

Answer 22

• sever vitamin D deficiency (adult form of rickets)
• invloves low calcium - low blood calcium
• remember bone is in a constant state of turnover
• new bone matrix is laid down but not mineralized properly
• RARE
• bending of the spine, bowing of legs

Question 23

Who could osteomalacia affect?

Answer 23

• could occur in women who:
• low calcium intake and low sun exposure
• multiple pregnancies and lactation

Question 24

What is osteoporosis

Answer 24

- disease related to calcium deficiency - amount of bone - reduced density - increased susceptibility to fracture; especially at wrsit, spine and hi

Question 25

How is osteoporosis different from osteomalacia?

Answer 25

- No change in composition of bone - rather, loss of overall amount of bone

Question 26

What are the types of bone compartments ?

Answer 26

1. Cortical 2. Trabecular

Question 27

What is cortical?

Answer 27

- A bone compartment - is approx 80% of skeleton - dense bone tissue, shafts of long bone, outer hard shell of flat bones - calcium loss is slow

Question 28

What is trabecular?

Answer 28

- A bone compartment - inner structural matrix - at ends of long bones, inside cortical shell of flat bones - loses calcium readily; calcium loss is faster

Question 30

What is type I osteoporosis

Answer 30

- rapid bone loss - 50 to 70 years old - due to rapid loss of estrogen in women following menopause - due to decrease in testosterone in men with advancing age - more common in women - primary trabecular bone - wrist and spine fractures

Question 31

What is type II osteoporosis

Answer 31

- slower bone loss - >70 years old - due to aging factors (reduced calcium absorbtion, increased risk of falling, increased bone and mineral loss) - both trabecular and cortical bone - hip fractures

Question 32

What is a measurement of vitamin D status?

Answer 32

- 25OH-D3 (calcidiol) - biomaker of vitamin D exposure from food, supplements and sun exposure

Question 33

What were the results and what was used to measure the vitamin D status of people 3 to 79 years of age from the Canadian Health Measure Survey 2012-2019?

Answer 33

- measured using serum 25(OH)D - prevalence of inadequaacy was 19%

Question 34

Is vitamin D a concern for older adults and why?

Answer 34

- yes - reduced dietary intake - low use of supplement - less time outdoors - less cutaneous syntehsis due to thinning of the skin

Question 35

What is vitamin D and calcium toxicity called?

Answer 35

- hypervitaminosis D - results in enhanced calcium absorbtion - symptoms: hypercalcemia, loss of appetite, fatigue, irritability, headache,

Question 36

What os the result of hypervitaminosis D and what is it

Answer 36

-toxicity of vitamin D and calcium - result is calcinosis - deposition of calcium in soft tissues - blood vessels - heart, kidney, lungs, kidney stones, tissue around joints

Question 37

What happened to the use of vitamin D drops leading to kidney failure in a 54-year-old man and give details about the article

Answer 37

- case of vitamin D toxcity from Toronto - 12 drops daily, or 12,000 units of vitamin D for 2 years - developed kidney failure, due to high blood levels of calcium that led to deposits of calcium in the kidney

Question 38

What are the vitamin D and non-skeletal health outcomes

Answer 38

- active area of research - cancers - CVD - diabetes - multiple sclerosis - immunity

Question 39

Explain vitamin D and multiple sclerosis

Answer 39

- substantial evidence to support a role for vitamin D - lower rates of MS closer to the equator and in people who get more sun exposure and have higher vitamin D status - very active area of reasearch

Question 40

Vitamin D and covid 19

Answer 40

- active area of research - lower rates of COVID-19 closer to the equator - inverse associations of covid-19 with 25(OH)D3 - similar risk factors for COVID-19 and vitamin D deficiency - may relate to vitamin D's role as a hormonal modulator of immune cells, whoch all have vitamin D receptors