The dietary history locked up in strands of hair can help diagnose eating disorders

Women with eating disorders often cannot recognise their problem, or attempt to disguise it. This makes diagnosis and treatment very difficult. But newly published research from Rapid Communications in Mass Spectrometry shows that analysing the carbon and nitrogen bound into hair fibres can determine whether a person does indeed have an eating disorder.

Hair grows by adding new proteins to the base of the strand, and pushing the strand up out of the hair follicle. The make-up of these proteins will be influenced by the nutritional state of the person at that moment. This nutritional state is in turn subtly affected by eating patterns associated with eating disorders. Because hair grows all the time, each strand consequently becomes a chemical diary, recording an individual’s day-by-day nutrition.

Research published this week by a multidisciplinary team of researchers at the Brigham Young University, Provo, Utah, USA, set out to analyse the pattern of carbon and nitrogen molecules in strands of hair.

The aim was to see if this pattern varied between people with eating disorders and others with normal eating behaviours. Careful statistical analysis of the data enabled them to give an 80% accurate prediction about whether a person had anorexia or bulimia – the two most common eating disorders. The test was so powerful that it required only five stands of hair.

“The test needs further validation before it will be ready for routine clinical use, but we believe that the current work shows that the method is already quite robust,” says lead author Kent Hatch of Brigham Young University’s Department of Integrative Biology.

“While some objective measures, such as low weight for age and height, aid in diagnosis of eating disorders, up until now doctors and researchers have had to rely heavily on self-reported information and qualitative interviews with patients. Data collected this way is often highly subjective and demands honesty from the patient. This test has the potential of providing an objective, biological measure for diagnosing eating disorders,” says Kent.