Adulteration of herbal weight-loss products with sibutramine - a drug used to treat obesity that was taken off the market several years ago on safety grounds – is sadly all too common.
Now, scientists in Turkey say they have shown that a lab technique known as attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) can be used to identify sibutramine in tea and coffee products that are sold as herbal weight-loss aids.
ATR-FTIR represents a "rapid, effective, non-destructive and cost-effective method for detection of sibutramine," they write in the journal Food Chemistry, adding that "unadulterated and adulterated tea and coffee samples could be perfectly discriminated with respect to their sibutramine contents…without any sample preparation."
"Discrimination of all samples in relation with their sibutramine content was accomplished at 100% accuracy," they conclude.
Sibutramine was sold by Abbott Laboratories until 2010, when it was removed from sale after being linked to an increased risk of cardiovascular events and strokes. It is now classified as a Schedule IV controlled substance.
The FDA notes that the drug is known to substantially increase blood pressure and/or pulse rate in some patients, and may present "a significant risk for patients with a history of coronary artery disease, congestive heart failure, arrhythmias or stroke."
The FDA has uncovered dozens if cases in which herbal and dietary supplements, foods and beverages have been adulterated with sibutramine, presumably to try to ensure the weight-reducing "efficacy" of the products, and this is also increasingly being seen in Turkey, say the researchers.
"Herbal alternative slimming intakes and dietary supplements are significantly valued by the people who are trying to struggle with obesity and weight loss," writes the team from Yıldız Technical University in Istanbul.
They note that consumers tend to prefer herbal products which are from natural sources such as green tea, green coffee and mixed herbal tea, as they are perceived as being safe.