What is Vitamin D
Vitamin D plays
several vital roles. It helps absorb and maintain the amounts of calcium and
phosphate in the body. These minerals are needed for strong bones and healthy
teeth.
In the introduction to my M.Phil thesis, I researched the factors that influenced bone formation and
reported that “the build-up of bone during childhood and
adolescence including genetic predisposition, diet, physical activity, body
composition and smoking (Cooper,
Westlake et al. 2006). Genetics
factors have been reported to account for almost 80 per cent of the variance in
peak bone mass (Davies, Evans et al.
2005; Bonjour, Chevalley et al. 2007).
As far as diet is concerned, certain
nutrition components have been extensively examined in the literature. Calcium
and vitamin D have received particular attention and their associations with
bone health in children and adolescents have been studied”.
Good sources of
vitamin D
Our skin is our
vitamin D factory and it needs an adequate supply of sunlight in order to make
vitamin D. Our diet is the second source of vitamin D which is present in:
- oily fish, such as salmon and sardines
- eggs
- fortified fat spreads
- fortified breakfast cereals
- powdered milk
The problem with
vitamin D sources, oily fish excluded, is that they all come with additional
risks. Cholesterol control is a risk with an egg-rich and fatty spread diets.
Breakfast cereals are normally sugar loaded and contain considerable salt
content.
Not enough D
and consequences
In a BBC article, it was proposed that we do not have enough sunlight in
this country. Hence our bodies fail to get the adequate dose needed to absorb
Calcium and Phosphate which are crucial to building and maintaining healthier
bones. Therefore, we could be exposing our children to higher risks in
contracting Rickets and exposing our elderly (particularly women) to higher
risks of Osteoporosis. In my M.Phil thesis I concluded that “Vitamin D deficiency has been reported as the cause of rickets among
children and acts to exacerbate osteoporosis in later life (Holick 2004).”
What is Osteoporosis?
Osteoporosis is a
medical complaint affecting the bones, whereby they become weak and breakable
under strains normal bones can withstand. The most common fracture sites are
the spine, wrist and hips. Other possible fracture sites are the arm or pelvis.
It is vital to build bone strength at a younger age and I reported in my
M.Phil. thesis that both nutrition and “impact” sports are crucial particularly
in the bone formation years part of life.
The importance
of bone formation
The following is published in my thesis and
highlights the bone formation years and their connection on preventing
Osteoporosis in later life:
“Childhood and
adolescence is a particularly important period in bone formation as the
skeleton undergoes accelerated growth with increasing annual deposits (also
known as Bone mineral density accrual) that enhance the bone’s mineral density.
The annual Bone mineral density accrual reach a peak in late adolescence (Bonjour, Chevalley et al. 2007). Bone mineral density accrual (growth per year) peaks at 12.54
years for girls and 14.05 years for boys. At these ages the maximum amount of
bone mineral density is deposited per year. The annual deposits then decline
until no further additions are made when girls reach approximately 17 years of
age and boys reach approximately 18.5 years of age (Cooper, Westlake et al. 2006). These bone deposits act as a reserve that is depleted throughout
life. The bigger the deposits the better the person is prepared for bone
fracture prevention in later life. The bone mass of an individual in later life
depends upon the peak attained during skeletal growth and the subsequent rate
of bone loss (Cooper, Westlake et al. 2006). The rate of bone loss is stable throughout early to mid
adulthood then bone is gradually eroded with age with an accelerated rate
during the 3-6 years of menopause in women (Bonjour, Chevalley et al. 2007). The graph below shows BMD variation with age (Bhattacharya 2010). It shows
that BMD values accelerate rapidly after birth and then start to slow down to a
peak which occurs roughly around 20 years of age. A plateau is then maintained
to the late 40s followed by a rapid decline.
Bone loss in
later years of life may lead to a condition known as Osteoporosis which is
characterised by low bone mass and the deterioration of bone’s
micro-architecture thus increasing the possibility of bone fracture (Jordan and Cooper 2002). Osteoporosis is a very common condition and is often undiagnosed
in clinical practice leading to devastating health consequences with fractures
in later life (Cooper, Westlake et al. 2006). In women, the occurrence of osteoporosis increases with age and has
been reported to affect 2 percent at 50 years of age and over 25 percent at 80
years (Bayly, O’Neill et al. 2006).
Figure
1‑2 The
prevalence of osteoporosis with age in”
Recommended
dose
The chief
medical officer for England, Dame Sally Davies, recommended in January this
year, that all pregnant and breastfeeding women, children aged six months to
five-years-old and the over-65s should take vitamin D supplements.
and over 100% of Calcium’s and
Phosphorous RDA.
Heba Al-Zuhair (M.Phil in Nutrition Physical Activity& Public Health )
