Too Much of a Good Thing
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.
