Selenium: safety, benefits, sources

[Guest guest]

[hsibaltimore.com]

 

Dear Reader,

 

A reasonable fear of selenium is not a bad thing. Especially if your

wife is mad at you.

 

A few years ago, a CSI plot featured two women who offed their spouses

by poisoning them with selenium. That's a fairly cumbersome way to kill

someone: it's not fast, and the obvious symptoms of selenium poisoning

would quickly reveal your homicidal scheme.

 

But for those of us who take supplements and have no plans to murder

anyone, it's useful to know that selenium is one of those nutrients

whose safe upper limit should be respected.

-----------

Pouring it on

-----------

The U.S. RDA for selenium is 55 micrograms (mcg) for women and 70 mcg

for men. And if you somehow managed to take, say, 3,000 mcg of selenium

per day, you would eventually begin to experience a toxic effect.

 

So imagine what sort of reaction you

might have if you started taking 40,000 mcg of selenium daily. That

actually happened recently when a batch of a liquid " full-spectrum "

supplement called Total Body Formula was mistakenly prepared with an

estimated 200 times the 200 mcg it was supposed to deliver.

 

Representatives for Total Body Essential Nutrition, Inc., quickly

removed their product from the market after more than 180 people became

sick with symptoms that included significant hair loss, muscle cramps,

diarrhea, joint pain, and fatigue. Fortunately, no one died, but one

person was hospitalized.

 

This being an election year, I'm surprised there wasn't a demonstration

on the Capital steps with a big crowd of puffed up Congressmen calling

for an all out ban on selenium supplements. Happily, we were spared that

scene. But it would be unfortunate if news of this isolated incident

prompted anyone to avoid selenium altogether, because this versatile

mineral provides your body with indispensable defenses against disease.

-----------

Calling back

-----------

Fruits and vegetables are generally good selenium sources, but only when

they're grown in selenium-rich soil. In the U.S., selenium is highly

concentrated in the soil of only six states: North and South Dakota,

Utah, Colorado, Montana and Wyoming. Bread, fish and meat also deliver

some amounts of selenium, but for most people a selenium supplement is

required in order to make that RDA of 55 or 70 mcg.

 

In previous e-Alerts I've looked at a number of studies that reveal the

benefits of keeping up an adequate selenium intake. Here are a few of

the highlights:

 

Selenium stimulates the immune system:

In an e-Alert in which HSI Panelist Allan Spreen, M.D., discussed

selenium, he said, " Both selenium and vitamin E are intimately

associated with stimulation of the part of the immune system dealing

with production of immunoglobulins. Strengthen immunity and lots of

problems go away. " In a trial that tested immune system response in

patients who took selenium supplements, researchers found that a daily

supplement of more than100 mcg may be necessary to provide optimal

protection.

 

Protection against cognitive decline:

When French researchers frequently measured selenium levels in nearly

1,400 elderly subjects over nine years, they found that subjects with

the greatest selenium decrease during the study period had the highest

probability of cognitive decline. Selenium levels naturally decrease

with age, which may contribute to decline in cognitive function.

 

Protection against cancer: Two human studies have revealed evidence that

high selenium levels are associated with the activation of a key

tumor-suppressing gene called p53. Dr. Martin L. Smith (the author of

one of those studies) noted that daily intake of selenium probably needs

to be around 200 mcg to ensure adequate protection.

 

Protection against colorectal cancer: In a study in which medical

records and blood tests from more than 1,700 subjects were analyzed,

results showed that those with the highest blood selenium values had

" significantly lower odds " of developing a colorectal tumor compared to

subjects with the lowest selenium levels. In addition, cancer patients

with the highest selenium levels had more than a 40 percent reduced risk

of tumor recurrence.

 

Protection against bladder cancer: In a study published in the September

2006 issue of the International Journal of Urology, researchers noted

that bladder cancer risk was lowered 14 percent for every 10 mcg/L

increase of selenium.

 

Selenium supports cardiovascular health: In a trial that tested a 110

mcg daily supplement of selenium, blood samples taken from 14 healthy

middle-aged subjects over 10 days showed that selenium prevented a

meal-induced increase in LDL oxidation.

 

Selenium helps control type 2 diabetes: Research shows that selenium

plays a role in insulin efficiency by improving glucose metabolism.

 

Talk to your doctor before adding selenium supplements to your daily

regimen.

 

Sources:

" CDC: Mounting Illness Reports Linked to Supplement " The Associated

Press, 4/18/08, ap.org