Vitamin D and Bone Health Flashcards
1
Q
Vitamin D
A
- 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
2
Q
What does Vitamin D do for Bone Health?
A
- Vitamin D - important for calcium balance
- Helps absorb calcium
- Helps retain calcium
Helps regulate blood levels of calcium
3
Q
Other Roles of Vitamin D
A
- Importance in cell differentiation
4
Q
Getting Enough Vitamin D
A
- 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
- Cholesterol turns into a different molecule when sunlight hits the skin
5
Q
People Who Absorb Less
A
- 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)
6
Q
Few Foods Contain Vitamin D Naturally
A
- 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
7
Q
Should I be Taking a Supplement?
A
- 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)
8
Q
What if I don’t get Enough?
A
- Rickets = soft bones
In children
9
Q
Osteomalacia
A
- Aching joints
Risk of fractures
10
Q
Vitamin D Toxicity
A
- Not possible with sun exposure
- Once you have enough your body stops making it
- Supplements:
- May cause hypercalcemia
- Excess is stored in fat tissue
11
Q
Vitamin D and Cancer
A
- 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
12
Q
Functions of Bones
A
- Structure and Support:
- Protect vital organs
- Metabolic Processes:
- Storage reservoir for minerals
13
Q
Osteoporosis
A
- Bone is porous and thinner
- Increases fracture risk
- With osteoporosis the sponge-like matrix is less dense with a lot of holes
14
Q
What Happens when Bones Fracture
A
- 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
15
Q
How do People Develop Osteoporosis?
A
- When bones are growing is when you can maximize their strength
- Physical activity is also important for growing and maintaining strong bones
16
Q
Changes in Bone Over Time
A
You reach your peak bone mass between 20-30 years old
17
Q
Process of Bone Remodelling
A
- Happens in 2 steps:
- Bone resorption:
- Breakdown of bone by osteoclasts
- Bone formation:
- Formation of bone by osteoblasts
18
Q
Peak Bone Mass
A
- The best thing to prevent osteoporosis is have healthy practices in childhood and teenage years
19
Q
Some Cool Facts about Physical Activity and Bone
A
- 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
20
Q
How do you know if your Bones are Healthy?
A
- Measured mineral density (BMD)
- Used to diagnose osteoporosis
- People who are at risk get measurements every few years
21
Q
Women have a Higher Risk of Osteoporosis than Men
A
- Lower peak bone mass
- Longer life expectancy
- Hormonal changes:
- During menopause Low estrogen levels cause higher bone resorption and low bone formation
