Junkfood Science: Hair-raising fears — When “high” isn’t really high

March 11, 2007

Hair-raising fears — When “high” isn’t really high

The evidence and misconceptions behind many of the scares about the safety of our fish due to methylmercury were recently examined. Now women are being increasingly frightened by claims of “high levels” of mercury found in their hair.

At an environmental event in Missoula, Montana, hair samples were gathered from 34 participants and tested at the Wisconsin State Laboratory of Hygiene. The Missoulian reported “State officials' hair tests high for mercury” and said six people (no pregnant women) had levels just above 1 part per million, the “safe limit for women of child-bearing age, pregnant and nursing women, and children younger than age 15.”

A popular tactic for gaining publicity has been to test normal, healthy people for exposures to toxins and terrify them when traces are found. Worse, these traces will be called “high” levels above “safe limits” to accentuate concerns. But as we learned, these reports often take advantage of the most innocent and vulnerable — expectant and nursing mothers and young children — but are not factual. The “high” levels aren’t high or unsafe at all.

The press release issued this week by the environmental group, Women’s voices for the Earth, and picked up by the media, admitted that their stunt was “to raise awareness about the pervasiveness of mercury pollution and to encourage support for Senate bill 423.” Yet, their press release provided the fodder the press picked up:

“I was shocked,” said Senator Gillan. “I did not expect to have mercury in my body, let alone have the highest result. This has made me realize that mercury contamination is a serious issue. We have to work to get mercury out of our environment.”

The actual report found that the traces in the hair samples ranged from 0.053 parts per million (ppm) to 1.58 ppm, with an average of 0.56 ppm. These are similar to the CDC’s National Health and Nutrition Examination Survey (NHANES 1999-2000), so were not unexpected at all. But the news failed to put these numbers into perspective for consumers. The facts would have negated any concerns and actually provided reassurance.

You’ll remember that the EPA’s controversial levels targeted for safety regulation were derived by first taking the level where there was no observed effect at all in the most sensitive of the population with a lifetime of exposure — a level of 12 ppm in the hair, a methylmercury level nearly ten times that found in American women — and adding another ten-fold safety cushion to that.

Mercury poisonings in Iraq in 1971-1972 from mercury-tainted grains were the earliest source for studies on levels resulting in health problems for unborn babies and children. While the mercury source was not fish, the levels offer an interesting perspective. According to a report published by United Nations Environment Programme, the International Labour Organisation, and the World Health Organization, “the highest no-observed-effect level for severe effects was 399 ppm” as measured in the mother’s hair.

The average 0.56 ppm in those tested would not concern healthcare professionals. As Dr. Elmer M. Cranton, M.D., of Mount Rainier Clinic, Inc., in Yelm, Washington explains, it is “highly unlikely that toxicity is responsible for symptoms unless the measured level is at least 10 time the upper limit on a laboratory report form.”

It’s easy to get creeped out and frightened when you’re told there are toxins in your body, but it’s nothing to fear. Below a certain level, there is no toxicity. Mercury is ubiquitous on our planet and humans have always been continuously exposed to low levels. It’s impossible to eliminate all exposure. It’s in all of us.

A note of caution

Researchers from Harvard Medical School recently published a study in the Journal of Occupational & Environmental Medicine, cautioning consumers about tests at spas and clinics that offer to test for mercury and other toxins. Their research found that in people labeled as “mercury toxic” after such commercial testing, none of them had actual evidence of mercury toxicity.

There are also a lot of questionable laboratories out there but even among the most-used U.S. laboratories, results of hair analysis can vary wildly. Researchers at the California Department of Health Services in Oakland recently examined hair samples analyzed in six commercial laboratories in the United States. Their results, published in the Journal of the American Medical Association, found laboratory differences exceeded 10-fold for 12 minerals and the designations for safe ranges also varied wildly. They cautioned that it is never advisable to make a diagnosis based on any single lab test result...

or let a number scare you.

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