This is an useful addition to the vitamin D debate. It tells us that
the blood threshold is measurable and clearly needs to be sustained
as a matter of course. It does not tell us if a move well above the
known threshold is beneficial or not. Certainly a deficiency is not.
I personally take 2000 iu every day, but have no idea what my blood
levels may be. Obviously something to remedy.
I really think research has neglected vitamin D in general because it
seems so easy.
ScienceDaily
(May 1, 2012) — In testing older patients' blood vitamin D
levels, there's uncertainty about where the dividing line falls
between enough and not enough. The threshold amount has become
controversial as several scientific societies set different targets.
To help resolve this
debate, University of Washington researchers conducted an
observational study. They wanted to learn how much vitamin D must be
circulating in the blood to lower the risk of a major medical event.
This category included heart attack, hip fracture, diagnosis of
cancer, or death.
Their findings are
reported May 1, in the Annals of Internal Medicine. Dr. Ian de
Boer, assistant professor of medicine in the Division of Nephrology
and a member of the Kidney Research Institute, led the project. He
also holds an appointment in the Department of Epidemiology, UW
School of Public Health.
Vitamin D is measured
in the blood as 25-hydroxy-vitamin D, abbreviated 25(OH)D.
The researchers tested
25(OH)D concentrations from a biorepository of blood samples of 1,621
Caucasian adults. These adults had enrolled in the early 1990s in the
Cardiovascular Health Study, originally designed to look at risk
factors and progression of heart disease in people age 65 and over.
The participants lived in one of four areas in the United States:
Forsyth County, North Carolina; Sacramento, County, California;
Washington County, Maryland; and Philadelphia, Pennsylvania.
Over about an 11-year
follow-up, researchers looked at the association between each
individual's 25(OH)D test results and the time that a first defining
medical event occurred. Among the participants, 1,018 had such an
event. There were 137 hip fractures, 186 heart attacks (myocardial
infarctions), 335 incidents of cancer, and 360 deaths.
Through their
statistical analysis, the researchers concluded that the risk of
these disease events rose when the concentration of 25(OH)D fell
below 20 ng/milliliter or 50 nmol/liter. "Our results," de
Boer said, "lend support to the threshold level recently
recommended by the Institute of Medicine, a national, independent
government advisory group."He added, "This target level for
adults is considerably lower than that set by other expert panels.'
His research team also
found that the association of low 25(OH)D blood concentrations with
risk of major disease events varied with the season. Because people
soak up most of their Vitamin D from the sun, their levels run
highest in the summer and lowest in the winter. Levels in autumn are
generally above those in spring.
"In evaluating
health risk," the researchers concluded, "Season-specific
targets for 25(OH)D blood concentration may be more appropriate than
a static target when evaluating patients health risk.
"Future research
in this area, de Boer said, will require clinical trials. Researcher
will look, for example, at the health effects of attempts to raise
25(OH)D in patients whose levels fall below the target. Interventions
might include supplements, dietary changes and increasing outdoor
activity.
"Sun exposure is
tricky," de Boer said, "because people have to protect
themselves from skin cancer and other sun damage." Sunscreen
blocks the UVB waves responsible for producing Vitamin D. Food
sources for Vitamin D are milk, fortified juice and cereal and oily
fish like salmon, mackerel, cod and herring.
Vitamin D provides
many different beneficial effects on health because it is actually
not a vitamin, but a prohormone. It can suppress the hormonal systems
that cause fluid to be retained and blood pressure to go up, modulate
the function of immune cells, and stop abnormal cells from
overgrowing.
In addition to de
Boer, other UW authors of the research paper, "Serum 25-hydroxy
vitamin D concentrations and risk of major clinical disease events in
a community-based population" are Gregory Levin and Mary L.
Biggs, Biostatistics; Cassianne Robinson-Cohen, Epidemiology; Andy
Hoofnagle, Laboratory Medicine; David Siscovick, Cardiovascular
Health Unit and Medicine and Epidemiology; and Bryan Kestenbaum,
Nephrology, Kidney Research Institute and Epidemiology.
The research was
funded by grants from the National Institutes of Health, including
the National Heart, Lung and Blood Institute, the National Institute
of Neurological Disorders and Stroke, the National Institute on
Aging, and the National Institute of Diabetes and Kidney Disease.
2 comments:
I think sun exposure is not tricky. You just have to know when is the right time to go outside for the sun exposure. By the way, I like your article. It's different from other articles about vitamin d. Very good research. You can also check this article - http://articles.mercola.com/sites/articles/archive/2008/12/16/my-one-hour-vitamin-d-lecture-to-clear-up-all-your-confusion-on-this-vital-nutrient.aspx. Another article about vitamin d.
thanks for sharing this about vitamin B2 riboflavin. I have take this already.
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