Head hair analysis is an unreliable tool to diagnose overall health and nutrition and should be viewed with skepticism by the public and ignored by physicians, researchers said on Tuesday.

A pair of California researchers provided hair samples from a single healthy volunteer to six US laboratories that perform 90 percent of the 225,000 hair mineral tests done annually.

The laboratories' findings of mineral content varied considerably, and they "also provided conflicting dietary and nutritional supplement recommendations based on their results," according to the report appearing in this week's Journal of the American Medical Association.

Nine US laboratories promote mineral analysis of hair as a diagnostic tool, and the public spends nearly $10 million a year on the tests that study authors Debra Gilliss of the California Department of Health Services in Oakland and Sharon Seidel of Impact Assessment Inc. concluded were worthless.

Their findings matched those of a 15-year-old study of hair analysis laboratories. The study found that the laboratories used varying testing methods on the samples, employed various reference points for mineral content and produced inconsistent results.

"Health care choices based on these analyses may be ineffective or even detrimental to the patient's overall health," the researchers said.

The results of hair analysis can be skewed by hair treatments, contamination from environmental sources and inconsistent lab techniques, the study authors said.

They recommended that doctors not use hair analysis to evaluate patients' exposure to environmental hazards or to assess nutritional issues. They also urged public health and consumer protection agencies to warn the public about the tests' unreliability.

An editorial in the journal supported the researchers' findings.

Written by Steven Steindel of the Public Health Practice Program Office at the Centers for Disease Control and Prevention in Chamblee, Georgia, and Peter Howanitz of the State University of New York, Health Science Center at Brooklyn, it questioned the value of hair analysis.

"Physicians and other health care professionals who are considering ordering hair analysis to assess nutritional status or who are basing nutritional counseling or therapy on hair analysis results should reconsider this approach unless and until the reliability of hair analysis value is established and evidence becomes available that clinical recommendations based on hair analysis improve patient outcomes," they wrote.

(From ChinaDaily)