An Australian man has died after swallowing 10,000 times the daily dose of selenium, reports The Age online newspaper. The 75-year-old mistakenly “purchased sodium selenite powder used primarily as a supplement for livestock, swallowing 10 grams.”

The man’s case is reported was reported October 2 in the Medical Journal of Australia (”Accidental death from acute selenium poisoning“).

According to The Age, Australian doctors who treated the 75-year-old “have used his death to highlight the dangers of promoting complementary medicines without adequate instructions.” The doctors blame the internet.

Selenium for human consumption, as sold in pharmacies, health stores and supermarkets , typically comes in 200 microgram (µg) pills or capsules, which may be printed “200 mcg.”

The Age reporter writes:

The unnamed man had searched the internet for possible prostate prevention and treatment after receiving an abnormal but unconfirmed test result, it was revealed in the latest Medical Journal of Australia.

He found websites discussing the benefits of selenium, an essential but highly toxic trace element found at low levels in seafood, grains and eggs.

In Australia, the element is marketed as a health supplement but the man mistakenly purchased sodium selenite powder used primarily as a supplement for livestock, swallowing 10 grams.

“Despite intensive care treatment he suffered a cardiac arrest and died six hours after ingestion,” wrote the staff who dealt with his case at Brisbane’s St Andrew’s War Memorial Hospital.

Internet searches found that the link between selenium and prostate cancer was mentioned on almost 300,000 websites.

“This case highlights the risks associated with failure to critically evaluate internet material and exposes the myth that natural therapies are inherently safe,” the authors wrote.

They said the World Health Organisation (WHO) had devised guidelines to help net surfers judge medical information on the web, available online through the Therapeutic Goods Administration.

But the specialists said more was needed, calling for an Australian database listing side effects of all current therapies.

“Adverse outcomes of complementary and alternative medicines should be better publicised and more stringently reported to the Adverse Drug Reactions Advisory Committee, the doctors wrote.

Cases of selenium poisoning are rare, with fewer than 20 reported worldwide before 1997.

Selenium is a trace mineral that is essential to good health but required only in tiny amounts. Many plant foods contain trace selenium, but the amount varies with growing region. Soil conditions vary by region and country. Worldwide, lowest selenium content in soil and plant foods is in China. In the USA, highest selenium levels are found in the high plains of northern Nebraska and the Dakotas. People living in those regions generally have the highest selenium intakes in the United States (U.S.) , but show no signs of toxicity. In Australia, University of Adelaide School of Agriculture reported last year that selenium levels in soil and in peoples’ blood is generally on the low side. They are considering biofortification to raise selenium levels in Australian wheat.

Individuals vary in their ability to absorb dietary selenium from the digestive tract. Illnesses like Chron’s disease affect selenium absorption and possibly so may aging.

Studies of whether daily dose of 200 micrograms (µg) prevents prostate cancer are ongoing in the USA (see links below). Selenium is included in a clinical trial of minerals and antioxidants underway in France. This trial, which began in 1994, has yielded preliminary results.

According to the US National Institutes of Health Fact Sheet on Selenium, “High blood levels of selenium (greater than 100 μg/dL) can result in a condition called selenosis [62]. Symptoms of selenosis include gastrointestinal upsets, hair loss, white blotchy nails, garlic breath odor, fatigue, irritability, and mild nerve damage [2].

Selenium toxicity is rare in the U.S. The few reported cases have been associated with industrial accidents and a manufacturing error that led to an excessively high dose of selenium in a supplement. The Institute of Medicine of the National Academy of Sciences has set a tolerable upper intake level (UL) for selenium at 400 micrograms per day for adults to prevent the risk of developing selenosis. ”

Sources and links:
Internet advice a health risk doctors warn The Age Oct 1, 2008

Dietary Supplement Fact Sheet: Selenium. Office of Dietary Supplements • NIH Clinical Center • National Institutes of Health

National Cancer Institute (NCI), USA, in its statement about selenium testing in the SELECT clinical trial, says:

What is selenium? Why study it for prostate cancer prevention?

Our bodies need selenium, a nonmetallic trace element that we get from food—especially plant foods like rice and wheat, seafood, meat, and Brazil nuts. Selenium is an antioxidant that might help control cell damage that can lead to cancer.

The Nutritional Prevention of Cancer Trial, published in 1996, included 1,312 men and women who had skin cancer. Men who took selenium to prevent nonmelanoma skin cancer received no benefit from selenium in preventing skin cancer. However, men who had taken selenium for 6½ years had approximately 60 percent fewer new cases of prostate cancer than men who took the placebo (2). In 2002, study data showed that men who took selenium for more than 7½ years had about 52 percent fewer new cases of prostate cancer than men who took the placebo (3). This study is one of the reasons selenium is being studied in SELECT. (See Question 11 for more information about selenium.)
# How much selenium is being used in SELECT? What risks might be involved?
11. How much selenium is being used in SELECT? What risks might be involved?

The amount of selenium (provided as l-selenomethionine) is 200 micrograms (µg) daily. Although the initial results of the Nutritional Prevention of Cancer Trial showed an overall decrease in cancer incidence from selenium, a 2003 update reported 17 percent more new nonmelanoma skin cancers in the selenium group compared with the placebo group (5). It is not clear how these results would apply to men who did not already have skin cancer when they enrolled in SELECT, or to men who are not at increased risk for skin cancer.

More about clinical trials of selenium:
Selenium in Treating Patients Who Are Undergoing Brachytherapy for Stage I or Stage II Prostate Cancer

Clinical Trials with Selenium - Prostate Cancer Prevention Program at the University Arizona