- As the sun begins to break through over Chicago, its
warming rays are resuming a critical role that has lain dormant most of
the winter, coaxing our skin to make vitamin D.
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- Emerging research indicates that vitamin D is more important
to our health than previously thought, leading an increasing number of
scientists to challenge whether the fear of sun exposure has made us cover
up too much.
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- Doctors are finding an increase in vitamin D deficiencies,
even as researchers discover remarkable results from the vitamin that affects
nearly every tissue in the body.
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- Told their pain and muscle weakness would only get worse,
and that they would likely remain in wheelchairs the rest of their lives,
five patients in Buffalo decided to take a chance on large doses of vitamin
D.
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- In 4 to 6 weeks they were up and about, saying goodbye
to their wheelchairs and back to normal activities, pain free.
-
- When women took vitamin D in multivitamin supplements
over a long period of time, their risk of developing multiple sclerosis
was reduced by 40 percent.
-
- And a disturbing number of children who don't have enough
vitamin D in their bodies are showing up with rickets, a crippling bone
disorder thought to have been eradicated more than 70 years ago.
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- Dr. Craig Langman, a kidney and mineral metabolism expert
at Children's Memorial Hospital and Northwestern University Medical School,
sees a new case of rickets every week, triple the rate of five years ago.
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- "We're finding more and more kids are presenting
with evidence of vitamin D malnutrition," said Langman, who noted
that includes fractures and bone pain.
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- Vitamin D is a critical hormone that scientists are discovering
helps regulate the health of more than 30 different tissues, from the brain
to the prostate. It plays a role in regulating cell growth, the immune
system and blood pressure, and in the production of insulin, brain chemicals
and bone.
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- "We thought that vitamin D was a very narrow-acting
substance," said Dr. Hector DeLuca of the University of Wisconsin,
where vitamin D was first identified in the early 1900s, leading to the
fortification of milk and some other foods that eliminated endemic rickets.
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- "The big surprise is that it's got a lot of important
biological effects that probably contribute to our health and we're just
now beginning to uncover them," said DeLuca. "Are we getting
enough vitamin D? No we're not, especially in the winter."
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- Vitamin D is one of the body's many control systems.
It acts like an emergency brake that helps stop cells from perilously misbehaving,
as immune cells can do when they cause such autoimmune diseases as MS and
as breast and prostate cells do when they turn cancerous.
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- Variable protection
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- This protection declines as vitamin D levels drop. University
of Chicago microbiologist Yan Chun Li discovered just how that happens
with high blood pressure. Vitamin D helps normalize blood pressure by keeping
a pressure-increasing switch called renin in check.
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- Vitamin D's importance for health goes back more than
750 million years to the earliest life forms that left the ocean for the
Earth's surface. All vertebrates today depend on sun exposure for vitamin
D production.
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- The lack of vitamin D is known to cause rickets, osteoporosis
and osteomalacia (soft bones). New research indicates that vitamin D malnutrition
may also be linked to many chronic diseases such as cancer (breast, ovarian,
colon and prostate), chronic pain, weakness, chronic fatigue, autoimmune
diseases like multiple sclerosis and Type 1 diabetes, high blood pressure,
mental illnesses--depression, seasonal affective disorder and possibly
schizophrenia--heart disease, rheumatoid arthritis, psoriasis, tuberculosis
and inflammatory bowel disease.
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- "A lot of people with aches and pains and marginal
weakness could be helped by vitamin D supplements," said Dr. Paresh
Dandona of the State University of New York at Buffalo who reported the
first five cases of vitamin D deficient myopathy three years ago in the
Archives of Internal Medicine.
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- Undiagnosed pain is the chief complaint of more than
one-third of patients.
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- Studying 150 children and adults with undiagnosed pain,
Dr. Greg Plotnikoff of the University of Minnesota discovered that 93 percent
were severely or profoundly vitamin D deficient. All were put on prescription
doses of the vitamin.
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- "One patient with chest pain had multiple balloon
angioplasties and his pain never went away," Plotnikoff said. "He
also had surgery for his low back pain but he didn't get any better.
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- "I measured his vitamin D level and it was basically
zero," he said. "His chest and low back pain were not due to
cardiac or spinal disease but to low vitamin D. We put him on prescription
strength vitamin D and he got much better. We had spent over $200,000 on
him in the hospital for these other procedures without doing a $20 blood
test."
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- A study in the British medical journal Lancet found that
infants receiving 2,000 IU of vitamin D daily were protected from developing
Type 1 diabetes. Various forms of vitamin D have become a major treatment
for psoriasis and preliminary evidence suggests it reduces blood pressure,
reduces hip fracture risks in older people and improves symptoms of rheumatoid
arthritis and multiple sclerosis.
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- Research help
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- "Our study supports a possible role for vitamin
D in the prevention of MS," said epidemiologist Kassandra Munger of
the Harvard School of Public Health. "Further studies are needed to
confirm the findings, but taking a multiple vitamin as part of a healthy
diet can't hurt."
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- Researchers are finding that the current recommended
daily allowances of vitamin D--ranging from 200 international units for
infants, children and adults up to age 50 years; 400 IU for men and women
from 50 to 70; and 600 IU for people older than 70--are probably far lower
than the minimum amount necessary for optimum health.
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- Scientists are quick to warn that although people may
need more vitamin D, mostly in the form of supplements in higher latitudes
where sunlight is weak during winter months, they should consult a physician
before consuming large doses. Taking too much vitamin D can elevate levels
of calcium in the blood, a potentially serious condition that can lead
to nausea, vomiting, or even death. It is especially easy for children
to overdose on vitamin D supplements.
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- Dr. Michael F. Holick of Boston University Medical Center,
one of the world's foremost vitamin D experts, recommends 1,000 IU daily
for everyone through a combination of safe exposure to sunlight and supplements.
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- Summertime sun exposure on the face, arms and hands around
noon for only 5 to 15 minutes for people with light skin 2 to 3 times a
week provides sufficient vitamin D, he said.
-
- Blacks have the highest risk for vitamin D deficiency
because dark skin needs 5 to 10 times more sunlight than white to produce
the same amount of the vitamin. One study found that 42 percent of African-American
women in the U.S. were vitamin D deficient.
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- Chronic diseases associated with vitamin D deficiency
are 25 to 50 percent more frequent in northern climates than among people
living closer to the sunny equator, where humans first evolved. As people
migrated away from the equator, it is thought, skin evolved lighter shades
to absorb more sunlight for vitamin D production.
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- Limited menu
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- Vitamin D is not available in most foods (oily fish,
egg yolks, liver and cod liver oil have some), but it is abundantly made
when sunlight strikes the skin, which normally produces about 90 percent
of the body's store of the vitamin.
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- People living in northern latitudes don't get enough
sun from December through February to make vitamin D. A person living in
Chicago, Boston, Detroit or New York can stand naked outside all day in
the winter and not make any vitamin D, said Holick, author of "The
UV Advantage."
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- Even in summer the skin's vitamin D-making ability gets
dampened from the increasing use of sunscreen, leading a growing number
of health experts to challenge the advice given over the last two decades
to avoid the sun at all costs in order to reduce skin cancer risk.
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- "The amount of vitamin D in our diet is totally
inadequate," Holick said. "We are in an era of sunphobia--that
is not being exposed to any direct sunlight--that's being promoted widely
by the dermatology community and it's probably hurting people's health
more than it's helping them."
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- "That message needs to be modified and moderated
to a more sensible approach so that people can get a little bit of safe
sun," he said.
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- The evidence is overwhelming that excessive sun exposure
causes skin cancer. More than 1 million cases of squamous and basal cell
cancers, which are highly treatable, are expected this year, according
to the American Cancer Society. Solar exposure is also blamed for the anticipated
55,100 cases of melanoma in 2004 and 7,910 deaths. Melonama, a potentially
deadly skin cancer, usually occurs years after severe sunburns in childhood.
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- Conflicting research
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- On the other hand, increasing but less conclusive evidence
suggests that adequate vitamin D levels from healthy sun exposure may reduce
the risk of many other cancers.
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- A recent study of more than 430,000 death certificates
showed that people who had more exposure to sunlight had a 26 percent lower
risk of death from colon and breast cancer, said D. Michal Freedman, an
epidemiologist at the National Cancer Institute.
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- Testifying in October at a "Vitamin D and Health
in the 21st Century" conference called by the National Institutes
of Health's Office of Dietary Supplements, William B. Grant, a retired
NASA senior scientist and solar radiation expert, said his studies determined
that lack of vitamin D accounts for 45,000 cancer deaths annually and 165,000
new cancer cases.
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- The conference was prompted by growing concerns of widespread
vitamin D inadequacy and how to strike a balance between supplements, dietary
fortification, tanning booths and sun exposure, said NIH nutritionist Mary
Frances Picciano.
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- "If you go to the literature where people are talking
about sunlight and cancer risk, nobody mentions that you need sun for vitamin
D," she said. "By the same token if you go to the vitamin D literature
where people are talking about skin irradiation to get vitamin D, nobody
talks about cancer.
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- "One of the first things that might be necessary
is to get the skin cancer people together with vitamin D requirement people,"
Picciano said. "There are questions that need to be addressed before
meaningful public health policy can go forward."
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- Copyright © 2004 Chicago Tribune
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