FT-NIR Spectroscopy
Fourier Transformation Near Infrared (FT-NIR) Spectroscopy
FT-NIR Spectroscopy is a measurement technique used to collect the spectrum of a substance in the near infrared region. Raw data is collected and then coverted to a spectrum using fourier tranformation. In other words, a snapshot of the chemical fingerprint of the substance is taken at a specific point in time.
In the case of measuring body fat, near infrared light, of low intensity, is pointed at the back of an indivdual's ear using a fibre optic probe. The reflected signal is then processed for absorption or reflectance characteristics. The spectrum is then compared to reference materials with known fat content to determine the individual's subcutaneous fat and the resulting percentage of body fat is given. The process takes less than one miunte to complete.
This technique is fast, accurate, reliable, non-invasive and cost-effective.
Is It Accurate?
An article, in the Obesity Journal (Nature Publishing Group), reported the research findings carried out at McMaster University, Ontario, Canada, comparing a convenient and non-invasive FT-NIR Spectroscopy to Dual-Energy X-ray Absorptiometry (DXA) in measuring fat content of premenstrual, overweight and obese young women. This study found a statistically significant linear relationship between the fat content, in kilograms, measured by FT-NIR and DXA. It concluded that the FT-NIR technology not only was low cost, easy to use and portable, but an accurate method to measure body fat content based on the study.
In a different study published in Lipids (a Springer publication), the results of body fat content measurements of 353 subjects, both male and female with varying body fat content, were cross-referenced indirectly with the body fat content of 420 subjects, again male and female, that had been determined using the Magnetic Resonance Imaging (MRI) technique. A high degree of correlation was obtained between the two measurements based on similar gender, age, height and weight.
The FT-NIR method for measuring body fat is comparable in accuracy to both MRI and DXA.