Vitamin D and Bone Health

Question 1

Vitamin D

Answer 1

• A fat soluble vitamin - stored in fat tissue
  
  • Also considered a hormone
  • Conditionally essential - we can make it ourselves if we are exposed to enough sunlight
    Need it but don’t necessarily need to eat it

Question 2

What does Vitamin D do for Bone Health?

Answer 2

• Vitamin D - important for calcium balance
  
  • Helps absorb calcium
  • Helps retain calcium
    Helps regulate blood levels of calcium

Question 3

Other Roles of Vitamin D

Answer 3

• Importance in cell differentiation

Question 4

Getting Enough Vitamin D

Answer 4

• Synthesize it from a form of cholesterol in our skin (need UV light from the sun)
  
  • Cholesterol turns into a different molecule when sunlight hits the skin
    Need a lot of things for sunlight to be converted to vitamin D

Question 5

People Who Absorb Less

Answer 5

• People with darker skin
  
  • People who live far from the equator
  • In Edmonton Alberta, people synthesize NO vitamin D between October and May
  • Up to 97% of Canadians have inadequate blood vitamin D levels during winter and or spring
  • People wearing sunscreen
  • People who stay indoors during the middle of the day (between 10am and 3pm)

Question 6

Few Foods Contain Vitamin D Naturally

Answer 6

• Oily fish - wild salmon, herring, trout
  
  • Most of out dietary vitamin D comes from fortified milk and margarine, yogurt and cheese do not have vitamin D added to them

Question 7

Should I be Taking a Supplement?

Answer 7

• Its recommended that men and women over 50 years of age take one
  
  • For you other folks, perhaps in the winter if you don’t drink a lot of milk and/or fatty fish
  • How much? A supplement containing the RDA (600-88IUs)

Question 8

What if I don’t get Enough?

Answer 8

• Rickets = soft bones

In children

Question 9

Osteomalacia

Answer 9

• Aching joints

Risk of fractures

Question 10

Vitamin D Toxicity

Answer 10

• Not possible with sun exposure
  
  • Once you have enough your body stops making it
  • Supplements:
  • May cause hypercalcemia
  • Excess is stored in fat tissue

Question 11

Vitamin D and Cancer

Answer 11

• There is emerging evidence that too much vitamin D may be related to increased risk of some cancers
  
  • Not sure where the sweet spot is, best to stay around the DRI values

Question 12

Functions of Bones

Answer 12

• Structure and Support:
  
  • Protect vital organs
  • Metabolic Processes:
  • Storage reservoir for minerals

Question 13

Osteoporosis

Answer 13

• Bone is porous and thinner
  
  • Increases fracture risk
  • With osteoporosis the sponge-like matrix is less dense with a lot of holes

Question 14

What Happens when Bones Fracture

Answer 14

• Wrist, hip and vertebrate of the spine are the most common ones
  
  • The fractures can be very painful and change the body, cause low self esteem

Question 15

How do People Develop Osteoporosis?

Answer 15

• When bones are growing is when you can maximize their strength
  
  • Physical activity is also important for growing and maintaining strong bones

Question 16

Changes in Bone Over Time

Answer 16

You reach your peak bone mass between 20-30 years old

Question 17

Process of Bone Remodelling

Answer 17

• Happens in 2 steps:
  
  • Bone resorption:
  • Breakdown of bone by osteoclasts
  • Bone formation:
  • Formation of bone by osteoblasts

Question 18

Peak Bone Mass

Answer 18

• The best thing to prevent osteoporosis is have healthy practices in childhood and teenage years

Question 19

Some Cool Facts about Physical Activity and Bone

Answer 19

• When astronauts go to space, they lose bone mass
  
  • Some have lost up to 20% of their bone mass
  • In zero gravity nothing is putting pressure on their bones making them weaker
  • Regain most it when they get back to earth
  • Tennis players have higher bone mass in their racquet arm compared to their other one

Question 20

How do you know if your Bones are Healthy?

Answer 20

• Measured mineral density (BMD)
  
  • Used to diagnose osteoporosis
  • People who are at risk get measurements every few years

Question 21

Women have a Higher Risk of Osteoporosis than Men

Answer 21

• Lower peak bone mass
  
  • Longer life expectancy
  • Hormonal changes:
  • During menopause Low estrogen levels cause higher bone resorption and low bone formation