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Vitamin D: How much do I need?

How much vitamin D do I need?
- No name / No state given


Mayo Clinic dietitian Katherine Zeratsky, R.D., L.D., and colleagues answer 
select questions from readers.
Answer
This is a good question without a simple answer.

It has long been known that vitamin D is crucial for healthy bones. Some 
research also suggests that vitamin D may play a role in preventing certain 
cancers and autoimmune diseases.

The National Academies of Sciences currently recommends 200 international 
units (IU) of vitamin D for children and adults up to age 50 and 400 to 600 
IU for adults older than age 50. However, researchers now question whether 
these levels are adequate for optimal health.

So, how much vitamin D is enough? There's still much debate about what the 
recommendations should be. But most researchers agree that a daily intake of 
800 to 1,000 IU would benefit many people — especially those at increased 
risk of vitamin D deficiency, including:

Babies who are exclusively breast-fed
Older adults
People with limited sun exposure
People with darker skin
People with fat malabsorption, such as due to celiac disease, Crohn's 
disease, pancreatic insufficiency, liver disease or cystic fibrosis
Many foods contain vitamin D, including fortified milk, cheese and yogurt. 
Sunlight is also a major source of vitamin D.

If you don't get the recommended amounts of vitamin D in your regular diet or 
from sun exposure, ask your doctor whether a vitamin D supplement is 
appropriate for you.


--- On Wed, 6/25/08, Tradingpost <tradingpost@lobo.net> wrote:

> From: Tradingpost <tradingpost@lobo.net>
> Subject: [Livingontheland] Lack of sunshine vitamin may cloud survival odds
> To: livingontheland@lists.ibiblio.org
> Date: Wednesday, June 25, 2008, 12:59 PM
> need another reason to be out in the garden?
> 
> Lack of sunshine vitamin may cloud survival odds
> Jun 23, 4:00 PM EDT
> By LINDSEY TANNER
> AP Medical Writer
> 
> CHICAGO (AP) -- New research linking low vitamin D levels
> with deaths from heart disease and other causes bolsters
> mounting evidence about the "sunshine"
> vitamin's role in good health.
> 
> Patients with the lowest blood levels of vitamin D were
> about two times more likely to die from any cause during
> the next eight years than those with the highest levels,
> the study found. The link with heart-related deaths was
> particularly strong in those with low vitamin D levels.
> 
> Experts say the results shouldn't be seen as a reason
> to start popping vitamin D pills or to spend hours in the
> sun, which is the main source for vitamin D.
> 
> For one thing, megadoses of vitamin D pills can be
> dangerous and skin cancer risks from too much sunshine are
> well-known. But also, it can't be determined from this
> type of study whether lack of vitamin D caused the deaths,
> or whether increasing vitamin D intake would make any
> difference.
> 
> Low vitamin D levels could reflect age, lack of physical
> activity and other lifestyle factors that also affect
> health, said American Heart Association spokeswoman Alice
> Lichtenstein, director of the Cardiovascular Nutrition
> Laboratory at Tufts University.
> 
> Still, she said the study is an important addition to an
> emerging area of research.
> 
> "This is something that should not be ignored,"
> Lichtenstein said.
> 
> The study led by Austrian researchers involved 3,258 men
> and women in southwest Germany. Participants were aged 62
> on average, most with heart disease, whose vitamin D levels
> were checked in weekly blood tests. During roughly eight
> years of follow-up, 737 died, including 463 from
> heart-related problems.
> 
> According to one of the vitamin tests they used, there were
> 307 deaths in patients with the lowest levels, versus 103
> deaths in those with the highest levels. Counting age,
> physical activity and other factors, the researchers
> calculated that deaths from all causes were about twice as
> common in patients in the lowest-level group.
> 
> Results appear in Monday's Archives of Internal
> Medicine.
> 
> The study's lead author, Dr. Harald Dobnig of the
> Medical University of Graz in Austria, said the results
> don't prove that low levels of vitamin D are harmful
> "but the evidence is just becoming overwhelming at
> this point."
> 
> Scientists used to think that the only role of vitamin D
> was to prevent rickets and strengthen bones, Dobnig said.
> 
> "Now we are beginning to realize that there is much
> more into it," he said
> 
> Exactly how low vitamin D levels might contribute to heart
> problems and deaths from other illnesses is uncertain,
> although it is has been shown to help regulate the
> body's disease-fighting immune system, he said.
> 
> Earlier this month, the same journal included research led
> by Harvard scientists linking low vitamin D levels with
> heart attacks. And previous research has linked low vitamin
> D with high blood pressure, diabetes and obesity, which all
> can contribute to heart disease.
> 
> The new research "provides the strongest evidence to
> date for a link between vitamin D deficiency and
> cardiovascular mortality," said Dr. Edward Giovannucci
> of the Harvard study of 18,225 men.
> 
> Low vitamin D levels also have been linked with several
> kinds of cancer and some researchers believe the vitamin
> could even be used to help prevent malignancies.
> 
> It has been estimated that at least 50 percent of older
> adults worldwide have low vitamin D levels, and the problem
> is also thought to affect substantial numbers of younger
> people. Possible reasons include decreased outdoor
> activities, air pollution and, as people age, a decline in
> the skin's ability to produce vitamin D from
> ultraviolet rays, the study authors said.
> 
> Some doctors believe overuse of sunscreen lotions has
> contributed, and say just 10 to 15 minutes daily in the sun
> without sunscreen is safe and enough to ensure adequate
> vitamin D, although there's no consensus on that.
> 
> Diet sources include fortified milk, which generally
> contains 100 international units of vitamin D per cup, and
> fatty fish - 3 ounces of canned tuna has 200 units.
> 
> The Institute of Medicine's current vitamin D
> recommendations are 200 units daily for children and adults
> up to age 50, and 400 to 600 units for older adults. But
> some doctors believe these amounts are far too low and
> recommend taking supplements.
> 
> The American Medical Association at its annual meeting last
> week agreed to urge a review of the recommendations.
> 
> ---
> 
> On the Net:
> 
> Archives: http://www.archinternmed.com
> 
> NIH: http://ods.od.nih.gov/factsheets/vitamind.asp 
> 
> http://hosted.ap.org/dynamic/stories/M/MED_VITAMIN_D_DEATHS?SITE=TXSAE&SECTION=HEALTH&TEMPLATE=DEFAULT
> 
> 
> 
> 
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