Does body fat protect you against osteoporosis or make
you more vulnerable to bone fractures? A new study by the
University of South Australia hopes to shed light on this
UniSA PhD candidate Mrs Deepti Sharma is recruiting 120
post-menopausal women - both lean and overweight - to test how a
person's body composition influences how they process calcium to
protect against bone loss and fractures.
"We know how much daily calcium someone needs to consume to help
protect against bone fractures later in life. However, it is not
known whether the recommended level or type of dietary calcium
should be adjusted depending on someone's body weight or their body
composition," says Sharma.
"People who are obese may have poor quality bones and may need to
adjust their calcium intake to account for this."
The trials form the second stage of Sharma's PhD thesis which also
looks at the role of vitamin D in bone health. She has undertaken
clinical trials of 111 RAH patients with hip fractures who are
undergoing surgery and analysed their bones for structure, gene
expression and their biochemical profile.
"What we have found is that high levels of vitamin D in the blood
are associated with improved bone structure.
"We have known for some time that people who have higher vitamin D
levels have reduced fractures. Now we are showing that vitamin D is
linked with improved activity in the bone and better quality of
bone. This is something which we have not previously been able to
see using standard bone mineral density tests," she says.
Sharma's supervisor, Associate Professor Paul Anderson, says the
findings could change clinical practice.
"Our findings not only suggest that vitamin D and calcium are
essential to prevent fractures but also that both may help improve
fracture healing," Assoc Prof Anderson says. "We now know that even
if you are in your 80s, if you have high levels of vitamin D you
can improve the quality of your bones."
Published data shows that up to 58 per cent of southern Australian
women are vitamin D deficient during winter due to a lack of sun
exposure. Even during summer, 42% of women are vitamin D deficient
due to lifestyle factors such as avoidance of the sun and the use
of sunscreen protection.
Prof Anderson says most people need to expose their face and arms
to some direct sunlight when the sun is high in the sky so that the
body can make vitamin D naturally.
"If that can't be achieved, it may pay to visit your GP to get a
blood test. If you are deficient in vitamin D, then taking a
supplement is a safe and effective way to restore vitamin D
"But when it comes to osteoporosis, it's not just about getting
enough vitamin D and calcium," Assoc Prof Anderson says. "Low
intensity, frequent, weight-bearing exercise is also crucial for
optimal bone health."