In my last post I discussed the CAM contention that metal poisoning is common and the scientific inaccuracies peddled, such as the claim that mercury poisoning causes autism. Once you have been sold on the fear, you naturally want to check whether you yourself are poisoned. CAM practitioners recommend hair analysis for this. Unfortunately.
This technique has been controversial for at least three decades; in 1983 a New York Times article alleged that the hair test industry was inconsistent, unscientific, fraudulent and dangerous to health:
In one case, a man was told that he had poisonous amounts of lead in his body and was started on chelation therapy with the drug EDTA to cleanse his system. But the excess lead turned out to be only in his hair, where it is harmless, and not in his body. Its source was a hair dye.
Had he continued much longer with the chelation treatments, he might have ”cleansed” his body of a number of essential nutrients, including calcium and magnesium, and possibly destroyed his kidneys with the drug.
In a similar case, a woman was told she had toxic amounts of selenium in her hair. Fortunately she consulted a physician before undergoing chelation therapy. Like the man above, the excess was only in her hair, not her body. Its source: the antidandruff shampoo she was using.
Wikipedia cites a 1985 investigation in which:
“Hair samples from two healthy teenagers were sent under assumed names to 13 commercial laboratories performing multimineral hair analysis. The reported levels of most minerals varied considerably between identical samples sent to the same laboratory and from laboratory to laboratory. The laboratories also disagreed about what was “normal” or “usual” for many of the minerals. Most reports contained computerized interpretations that were voluminous, bizarre, and potentially frightening to patients. Six laboratories recommended food supplements, but the types and amounts varied widely from report to report and from laboratory to laboratory. Literature from most of the laboratories suggested that their reports were useful in managing a wide variety of diseases and supposed nutrient imbalances. However, commercial use of hair analysis in this manner is unscientific, economically wasteful, and probably illegal.”
The authors did not explicitly rule out further diagnostic uses for hair mineral analyses in the future, but listed three issues that prevent hair mineral tests provided by the sampled labs from being accepted as scientifically sound and clinically viable: a lack of standardization and general agreement on the techniques by which hair mineral content was to be determined, a lack of general consensus on the meaning of hair mineral content analyses, and a lack of agreement on treatments for putative imbalances.
The labs suggested a variety of ‘abnormal conditions’ were indicated by the hair samples, none of which were actually present. These varied between samples from the same test subjects.
A second investigation in 2001 concluded that things had not improved:
Results Laboratory differences in highest and lowest reported mineral concentrations for the split sample exceeded 10-fold for 12 minerals, and statistically significant (P<.05) extreme values were reported for 14 of the 31 minerals that were analyzed by 3 or more laboratories. Variations also were found in laboratory sample preparation methods and calibration standards. Laboratory designations of normal reference ranges varied greatly, resulting in conflicting classifications (high, normal, or low) of nearly all analyzed minerals. Laboratories also provided conflicting dietary and nutritional supplement recommendations based on their results.
Conclusions Hair mineral analysis from these laboratories was unreliable, and we recommend that health care practitioners refrain from using such analyses to assess individual nutritional status or suspected environmental exposures. Problems with the regulation and certification of these laboratories also should be addressed.
I think it is fair to say that hair analysis alone should not be relied upon to determine environmental exposure to metal pollutants. Many CAM practitioners do, however, and often recommend dangerous chelation therapy based on such dubious analysis. I’ll write more on this in a later post.