Nutratech tests Advantra Z for blood pressure risk
ingredient Advantra Z does not contain meta-synephrine, an isomer
that has the potential to raise blood pressure, following testing
at an independent laboratory.
The New Jersey ingredient supplier took the decision to have Advantra Z analyzed following the publication of a technical report in the April issue of the International Journal of Obesity(29, 443-446), entitled 'Exactly which synephrine alkaloids does Citrus aurantium (bitter orange) contain?'.
The report identified at least one citrus aurantium-containing product on the market that contains both meta-synephrine and para-synephrine, an isomer that is not thought to pose the same danger.
Citrus aurantium is commonly used in weight loss preparations, and it is believed that product sales have increased significantly since the ban on ephedra-containing products came into effect in April 2004.
According to Mintel's Global New Products Database, two of the seven weight loss products launched in the US in 2004 contain citrus aurantium.
In the past, questions have been raised over the safety of citrus aurantium as it is similar in structure to ephedra. A review article published in the September 2004 issue of Experimental Biology and Medicine claims there is no scientific evidence to support the use of this herb for losing weight and that it may even be dangerous for the consumer's health.
"Although no adverse events have been associated with ingestion of [citrus aurantium and symephrine]", wrote researchers from Georgetown University, "synephrine increases blood pressure in humans and other species, and has the potential to increase cardiovascular events."
But the IJO report noted that the six possible isomers of synephrine (para, meta, ortho; and for each one of these there is a 'd' or 'l' form) do not all have the same pharmacological properties, and therefore the same safety and efficacy.
The two most common forms are meta and para. It is meta-synephrine that is said to cause the narrowing of blood vessels, and is therefore linked with raised blood pressure.
The authors of the technical report were unable to identify published data that explicitly shows whether CA contains para-synephrine, meta-synephrine or both, but they did show that at least one product purportedly containing synephrine alkaloids from citrus aurantium contains both.
"Their report confirms that it is not possible to rely on ingredient labels of OTC weight reduction preparations, and additional studies should be performed to determine if ingredients that may cause harm are present," wrote the journal editors.
Nutratech's ingredient was tested at Chromadex laboratory, which was contracted by the office of Dietary Supplements to determine a method for evaluating synephrine alkaloids.
Company president Bob Green said that Chromadex's findings mean manufacturers can prevent questions being raised over their ingredients labels by including the words 'contains patented Advantra Z'.
