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 a fast, accurate, reliable, cost-effective and non-destructive method.
Is It Accurate?
A study of 353 subjects with varying body types was done to establish the validity of the FT-NIR method for fat content measurement. FT-NIR measurements were cross-referenced indirectly with 420 subjects that underwent a fat content measurement study using the MRI method. A high correlation was obtained between the two measurements based on similar, gender, age, height and weight. A new study directly compared FT-NIR with DXA fat content measurement. The results on the same individuals showed a high correlation between the two methods.
FT-NIR method for measuring body fat is comparable in accuracy to both MRI and DXA.