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HEALTH
Vitamin
D can lower risk of death by 7 per cent
Taking vitamin D has been found to have a
new benefit: It appears to be a life extender, according to a new study.
Researchers who pooled the results of 18
separate experiments conducted in several industrialized countries reported
that people who were given a vitamin D supplement had a 7-per-cent lower
risk of premature death than those who were not.
The pooled results were from experiments
conducted in the United States, Germany and Britain, among other countries,
and included more than 57,000 participants.
For reasons that are not yet fully
understood, those who received vitamin D had a lower chance of dying
prematurely than those given dummy pills, or placebos, in the experiments,
said the study published yesterday in the Archives of Internal Medicine.
"Mechanisms by which vitamin D supplements would decrease all-cause
mortality are not clear," said the study's authors, Philippe Autier of
the International Agency for Research on Cancer in Lyon, France, and Sara
Gandini of the European Institute for Oncology in Milan, Italy.
Earlier research has indicated that vitamin D deficiencies are associated
with higher risks of contracting major illnesses such as cancer, which
account for 60 to 70 per cent of deaths in high-income countries.The study
speculates that the vitamin, which is used in organs and tissues throughout
the body, may cut death rates by inhibiting the proliferation of cancerous
cells.
Vitamin D is also known as the sunshine vitamin, because it is produced
in naked skin that is exposed to strong sunlight.
Many medical experts believe people living in northern countries have a
chronic deficiency of the vitamin in winter, when the weak sunlight does not
lead to creation of the nutrient in skin.
Although most of the vitamin D people have is made in their skin, it is
also available in supplement form and in some foods.
The European study tracked the participants in the various experiments
for an average period of 5.7 years, taking note of whether those dying had
been given the vitamin.
There were 4,777 deaths from all causes among the group.
Those experiencing the lower risk of dying took daily doses of vitamin D
ranging from 300 to 2,000 international units, with the average 528 IU.
Most commercially available multivitamins contain between 400 and 600 IU.
Health Canada currently recommends a sliding scale of vitamin D
supplementation, with the amounts rising gradually as a person ages.
For those younger than 50, it recommends 200 IU a day. That amount rises
to 400 IU from age 51 to 70, and 600 IU for those 71 and older.
However, the government agency says taking up to 2,000 IU is safe, and
the Canadian Cancer Society earlier this year recommended taking 1,000 IU
daily as a cancer prevention step.
Some foods - for example, oily fish like salmon and sardines - are a
natural source of the vitamin.
Milk is commonly fortified with 100 IU per cup.
In a separate editorial in the journal, Edward Giovannucci of the Harvard
School of Public Health and one of the world's leading researchers on
vitamin D, said evidence of the nutrient's health effects are so strong that
doctors should start testing their patients' vitamin D levels and treating
those with deficiencies.
The new study "adds a new chapter in the accumulating evidence for a
beneficial role of vitamin D on health," Dr. Giovannucci said.
"From a broader public health perspective, the roles of moderate sun
exposure, food fortification with vitamin D and higher-dose vitamin D
supplements for adults need to be debated," he said.
Dr. Giovannucci also said North Americans may be inadvertently
contributing to their vitamin D deficiencies through sun avoidance in an
attempt to prevent skin cancer. - GLOBE
& MAIL 2007 September 11
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