The Vitamin-D Debate: How Much is OK?
by ilene - September 6th, 2010 2:30 am
The Vitamin-D Debate: How Much is OK?
By Alice Park, courtesy of TIME
Spend a few minutes soaking up some rays and your body will start to pump out more vitamin D. Many health officials believe Americans are D-deficient, but in the age of sunblock and self-tanners, how many vitamin-D pills should we be popping? New guidelines for the optimal dietary dose are expected in the fall, and definitive studies on vitamin D’s effects on cancer, heart disease and cognition are ongoing. In the meantime, here’s where the science stands.
Cancer
Vitamin D may prevent cancer by suppressing the cell growth and blood-vessel formation that feed tumors. At least that’s the idea, based on animal studies and analyses of human cells. But trials in which patients take vitamin D have not shown a consistent lowering of cancer risk.
One four-year trial of 1,200 postmenopausal women found a 77% lower risk of all cancers among those taking calcium and 1,000 IU of vitamin D a day than among those taking a placebo. A larger study, however, in which subjects took 400 IU of vitamin D — in the absence of an official daily recommended intake, that’s the "adequate" intake for adults ages 51 to 70 — did not show lower breast-cancer risk.
The data are strongest for colorectal cancer: subjects with higher blood levels of vitamin D were half as likely as those with lower levels to develop the disease.
Heart Disease
Studies on animals and human-cell cultures indicate that vitamin D has a protective effect on the heart, controlling the release of stress hormones that lead to high blood pressure and inflammation.
Studies on human subjects confirm this link. In one trial, men whose blood work showed D levels below 30 nanograms per milliliter — the amount the Institute of Medicine says adults should aim for — were twice as likely to have a heart…
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Turning Sunshine into Performance?
by ilene - November 7th, 2009 9:03 pm
Turning Sunshine into Performance
By Ilene
Does vitamin D have anything to do with investing and stock and options trading? Maybe. Preliminary research suggests that lack of vitamin D is associated with impaired mental abilities. And this may indicate that obtaining sufficient levels of vitamin D may improve cognitive performance.
Researchers stopped short of advising more sunshine, or fruit-flavored gummy D supplements (yum!), to improve one’s cognitive function. But further research is warranted.
In addition, and perhaps most importantly, many children appear to be deficient in vitamin D (see below) so it may be worth investing in some of those gummy Ds.
Does Vitamin D Improve Brain Function?
New studies show low vitamin D levels may impair cognitive function
By Diane Welland, in Scientific American
The push to prevent skin cancer may have come with unintended consequences—impaired brain function because of a deficiency of vitamin D…
“We know there are receptors for vitamin D throughout the central nervous system and in the hippocampus,” said Robert J. Przybelski,… “We also know vitamin D activates and deactivates enzymes in the brain and the cerebrospinal fluid that are involved in neurotransmitter synthesis and nerve growth.” In addition, animal and laboratory studies suggest vitamin D protects neurons and reduces inflammation.
Two new European studies looking at vitamin D and cognitive function have taken us one step further…
The scientists found that the lower the subjects’ vitamin D levels, the more negatively impacted was their performance on a battery of mental tests…
A second study, led by scientists at the University of Manchester in England… looked at vitamin D levels and cognitive performance in more than 3,100 men aged 40 to 79 in eight different countries across Europe. The data show that those people with lower vitamin D levels exhibited slower information-processing speed…
Although we now know that low levels of vitamin D are associated with cognitive impairment, we do not know if high or optimum levels will lessen cognitive losses. It is also unclear if giving vitamin D to those who lack it will help them regain some of these high-level functions…
See Also:
Vitamin D for Quicker Thinking?
Men With Low Blood Levels of Vitamin D Fare Worse on Test Requiring Speedy Thinking
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Philip R. Davis is a founder Phil's Stock World, a stock and options trading site that teaches the art of options trading to newcomers and devises advanced strategies for expert traders...
Ilene is editor and affiliate program
coordinator for PSW.