“The sunshine vitamin”.
Also known as calciferol. Our bodies
can produce vitamin D from sunlight’s
ultra-violet rays on our skin. Fat-soluble
vitamin. Commonly found in foods of
animal origin. I also call it “Bone
Vitamin No.1’ due to its importance
for healthy, strong teeth & bones.
(So what is “Bone
vitamin no. 2?)
Although we humans can produce vitamin
D from sunlight, due to the different
pigmentation of people from different
descents, the level we can produce
vitamin D will vary. A Caucasian will
need 20minutes of sunlight, 2-3 times
per week to get adequate vitamin D.
But a typical African-American with
deep skin pigmentation will require
double or triple the frequency and
duration to get a similar effect.
Please note that frequency and duration
will also depend on time of day, season,
weather condition (cloudy or sunny)
and location (the nearer you are to
the equator, the stronger the sun
intensity). The sun is at its strongest
between 10am to 4pm. It is best to
avoid overexposure during this time.
A word of warning: chronic excessive
exposure to sunlight increases the
risk of skin cancer. However there
is little evidence that sensible,
moderate sun exposure increases the
risk of skin cancer. Due to beneficial
effects of vitamin D in preventing
many cancers, moderate sun exposure
may actually guard against cancer.
Because of the health benefits and
hazards of sun exposure. Get 10-20
minutes of direct sun exposure (depending
on sunlight intensity, skin pigmentation,
location) and apply a sunscreen after
that, if you intend to be exposed
for longer periods.
Vitamin D plays a major role in calcium
absorption. The relationship between
vitamin D and calcium absorption can
be described analogously as “a
key and a locked door”. Vitamin
D is the key that unlocks the door
allowing calcium to leave the intestine
and enter the bloodstream. In order
for calcium to be effective, we need
vitamin D. A vitamin D deficient individual
will only be able to absorb 10 to
15 percent of the calcium in their
diet. An individual with adequate
vitamin D can absorb 30 per cent.
30 per cent does not sound like much,
but that is at least double the amount
of a vitamin D absorption compared
to a vitamin D deficient individual.
30 per cent absorption rate is normal
for most healthy individuals, but
during pregnancy, lactation and growth
spurts (eg. teenagers), the body responds
appropriately by increasing the absorption
rate to up to 80 per cent.
Vitamin D also works in the kidneys
to help retain calcium that would
otherwise be lost.
There also is evidence that vitamin
D is able to prevent cancer. The highest
incidence of colorectal and breast
cancer is in areas where people are
least exposed to natural light. The
dietary form of vitamin D has been
shown to inhibit tumour growth. There
have been links between breast cancer,
prostate cancer, colon cancer and
vitamin D deficiency. Studies in the
USA and Europe have shown that vitamin
D can decrease the risk of getting
and dying from colon cancer, prostate
cancer, ovarian cancer and breast
cancer by 50 per cent.
The active form of vitamin D is ‘activated’
by the kidney, and is called 125-dihydroxy
vitamin D. This activated form of
vitamin D is responsible for instructing
the intestines to absorb calcium from
our diet more efficiently, for ensuring
our blood calcium is normal thus enabling
healthy strong bones.
People who have severe liver problems/disease
may have problems absorbing vitamin
D (because vitamin D is a fat soluble
vitamin, and liver aids in fat digestion).
There has been evidence that obese
individuals are prone to vitamin D
deficiency. This is due to vitamin
D getting embedded deep in the fat
tissues and unable to be used effectively
by the body.
Vitamin D is also important for proper
muscle functioning. A study done in
Minnesota by Dr. Plotnikoff during
winter, where 150 individuals ranging
from children in the early teens right
up to seniors of age 65, were complaining
of muscle and bone aches/pains. 93
per cent of this group were found
to be vitamin D deficient.
There is a concern that the American
population (up to 40 per cent) is
vitamin D deficient. However, do not
go overboard in vitamin D supplementation,
as vitamin D is the most toxic of
all the vitamins.
Prevents rickets (a disease of growing
children – causing softening
and deformity of the bones especially
those under stress. eg. legs).
Promotes absorption of calcium, iron,
magnesium, zinc and other minerals.
Protects against osteoporosis.
May help in the treatment of psoriasis.
Boosts the immune system.
Necessary for strong teeth and bones.
Necessary for proper muscle functioning.
May help to prevent certain types
of cancer (colon cancer, prostate
cancer, ovarian cancer and breast
Muscular weakness and spasm.
Lack of vigour.
Natural (food) sources
Fatty fish (herrings, kippers, salmon
Cod liver oil and halibut liver oil.
U.S: RDA: 10mcg
EU RDA: 5 mcg
Supplementation up to 200-400 IU or
5-10 mcg is ok.
Caution: High doses can be toxic.
(Do not exceed 1,000 IUs per day).
More info >> Nutrient
Vitamin D is the most toxic of all
the vitamins. Symptoms include: nausea,
vomiting, headache and depression,
constipation, and anorexia.
More severe symptoms: confusion,
high blood pressure, kidney failure
(Last updated: 16