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Vitamin D Deficiency: Back to the
Future?
 Auburn,
May 2, 2003
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Vitamin D deficiency. Scientists once thought they had this problem
licked. Now it appears they still have some work to do.
Vitamin D is the
easiest or the most elusive vitamin to obtain, depending on who you
are.
Adults typically
can make this vitamin merely through adequate sunlight exposure on the
skin – as little as 10 to 20 minutes a day.
Adequate amounts
of vitamin D also can be obtained from milk and dairy products, which
have been fortified since scientists uncovered a link between vitamin
D and the debilitating disease known as rickets. Rickets, a disease
that abounds in Charles Dickens novels set in the dark, soot-ridden
streets of 19th century industrial London, is reflected in
skeletal abnormalities – the result of inadequate amounts of vitamin D
received during childhood.
Even today, long
after health experts declared victory and trained their sights on
seemingly more pressing nutritional concerns, vitamin D deficiencies
are still a risk among the very old -- elderly people who can’t obtain
adequate amounts of the vitamin from sunlight or dairy products – and
the very young – breast-feeding infants.
Osteoporosis, a
crippling bone disease, is often the price of vitamin D deficiency
among older people. Until recently, health experts assumed that the
risk of osteoporosis was best addressed by consuming adequate amounts
of calcium.
As it turned out,
a key ingredient was missing – vitamin D.
“The problem
associated with vitamin D deficiency stems from stressing calcium as
the only safeguard against bone disease,” says Dr. Robert Keith, an
Alabama Cooperative Extension System nutritionist and Auburn
University professor of nutrition and foods.
“They were right –
you need your calcium. But as they soon learned, this strategy didn’t
work as well as they had hoped because older people still weren’t
getting adequate amounts of vitamin D, which also provides a crucial
safeguard against brittle bones.”
“So now, the rule
of thumb is to consume amounts of calcium and vitamin D.”
For older people,
the current recommendation for vitamin D is 600 IUs daily.
Breast-feeding
infants are also prone to vitamin D deficiency, but for different
reasons.
“We tend to think
of breast milk as the perfect baby food;” Keith says, adding, “it
really is the gold standard.”
“Nevertheless,
breast milk, unlike baby formula, does fall short of vitamin D.”
“It’s almost like
Mother Nature is saying, ‘I don’t need to put too much vitamin D into
this milk because the baby’s going to be out in the sun,’” Keith
observes. “And three or four thousand years ago, that certainly was
the case. Women were out in the garden carrying their infants or
strapping them to their backs – a virtual guarantee that they would
produce sufficient amounts of vitamin D from the exposure to
sunlight.”
Today, though, for
a variety of reasons – often because mothers are afraid to expose
their infants to potentially harmful ultraviolet rays – fewer infants
are exposed to adequate sunlight. And this presents a special problem
for those who breast-feed.
Experts recommend
that breast-fed infants receive between 100 and 200 IUs of vitamin D
each day.
Likewise, for some
elderly people, obtaining the right amounts of vitamin D often isn’t
easy. In many cases, lactose intolerance prevents them from obtaining
adequate amounts of vitamin D from milk and dairy products. Even
sunlight exposure is no guarantee, since elderly people don’t make the
vitamin in their skin as readily as younger people.
For these people,
daily calcium supplements fortified with adequate amounts of vitamin D
are the only alternative, though Keith says these should be taken only
after consultation with a physician.
For breast-feeding
infants, he says, the problem is less challenging, since even short
but consistent exposure to sunlight can provide adequate amounts of
the vitamin.
“We’re talking
about 10 or 20 minutes a day, during which half the baby’s body is
exposed – not long enough to cause significant tanning or sunburn but
long enough to ensure they get enough exposure to make adequate
amounts of vitamin D.”
Mothers also
should consult with their baby’s pediatrician to explore other vitamin
D supplement options in addition to breast-feeding, Keith says.
(Dr.
Robert Keith, Alabama Cooperative Extension System Nutritionist
and Auburn University Professor of Nutrition and Foods, 334-844-5686.)
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