Standing Guard

“Strengthen immunity and lots of problems go away.”

That insight comes from a previous e-Alert in which HSI Panelist Allan Spreen, M.D., discussed the merits of combining vitamin E and the mineral selenium.

Dr. Spreen: “Both selenium and vitamin E are intimately associated with stimulation of the part of the immune system dealing with production of immunoglobulins.”

What got me thinking about selenium and vitamin E? I came across a new study that suggests selenium may provide powerful protection against a cancer that affects mostly men.

Bladder benefits

Based on the results of previous dietary studies that have shown selenium to have potential cancer-fighting properties, a team of scientists at Katholieke Universiteit Leuven in Belgium launched a study to assess the effect of the mineral on bladder cancer.

STUDY ABSTRACT

• Researchers recruited 178 subjects who had been diagnosed with bladder cancer
• More than 360 healthy subjects were also recruited
• Analysis of blood samples revealed that subjects with more than 96 micrograms per liter (mcg/L) of selenium, reduced their risk of bladder cancer by 70 percent, compared to subjects who had less than 82.4 mcg/L
• Risk was cut by more than half among those whose selenium levels were between 82.4 and 96 mcg/L

Writing in the September 2006 issue of the International Journal of Urology, the researchers noted that bladder cancer risk was lowered 14 percent for every 10 mcg/L increase of selenium.

Putting a lid on p53

This isn’t the first time I’ve reported about research on selenium as a cancer-fighter.

In the e-Alert “Dirt Rich” (12/7/04), I told you about a colorectal tumor study from the University of Arizona in which medical records and blood tests from more than 1,700 subjects were analyzed to determine tumor developments and selenium concentrations. Results showed that those with the highest blood selenium values had “significantly lower odds” of developing a colorectal tumor when compared to subjects with the lowest selenium levels.

The researchers also noted that each of the three trials from which they gathered data indicated selenium’s protective effect against the recurrence of tumors, and that subjects with the highest selenium levels had more than a 40 percent reduced risk of tumor recurrence compared to subjects with the lowest levels of selenium.

Neither this study nor the Belgium study was designed to investigate the mechanism by which selenium might offer protection against cancer. But in the e-Alert “P53, Where Are You?” (6/26/03), I told you about two studies that offered clear evidence that high selenium levels were 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.

The U.S. RDA for selenium is 55 mcg for women and 70 mcg for men. As I’ve explained in previous e-Alerts, 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. Bead, fish and meat also deliver some amounts of selenium, but the Brazil nut can’t be beat: It contains more than 800 mcg of selenium per ounce.