A dossier of scientific data that convinced Health Canada and Intertek Cantox of the safety of bitter orange extract, synephrine, has been sent to Finnish authorities which recently banned weight loss products containing the stimulant, along with caffeine.
The dossier was compiled by the world’s leading bitter orange academic, Sidney J Stohs, PhD, Dean Emeritus at the Creighton University Medical Center in Nebraska. He said the Finnish action was, “clearly not supported by current scientific research.”
“They are based on unsubstantiated conjecture and not scientific fact.”
“Approximately 25 human published and unpublished human clinical studies have been conducted which demonstrate that C. aurantium (bitter orange) extract and p-synephrine alone and in combination with other ingredients including caffeine support modest weight loss and energy production in conjunction with diet and exercise without significant adverse effects being observed,” Dr Stohs added.
A meta-analysis of the studies showed half of the subjects were overweight/obese, and 40% consumed caffeine (up to 528 mg/day) in combination with p-synephrine (up to 98 mg/day).
The data provoked Health Canada to downgrade its stance on synephrine to a ‘Type III health risk’, a class where products were, “not likely to cause any adverse health consequences.”
This was the case, Health Canada reasoned in a 49-page assessment, at intakes of 50 mg per day of p-synephrine alone in healthy adults, and 40 mg per day or less of p-synephrine when combined with 320 mg per day or less of caffeine.
Similarly Intertek Cantox, a consultancy and contract research organisation (CRO), had found that “p-synephrine is unlikely to have significant effects on inotropy, vasoconstriction, or blood pressure.”
Dr Stohs sent a similar dossier to German authorities (BfR) which issued a warning against synephrine+caffeine earlier in the year. Its stance has not changed however.
Synephrine is not ephedrine
EVIRA, the Finnish Food Safety Authority, said in its missive that synephrine acted in a similar way to the widely banned stimulant ephedrine, but Dr Stohs dismissed such a grouping and noted differences between synephrine forms.
“The structural (stereochemical) differences between p-synephrine relative to other biogenic amines as epinephrine, nor-epinephrine, ephedrine and m-synephrine result in markedly different adrenergic receptor binding and pharmacokinetic characteristics, and as a consequence markedly different pharmacological properties.”
“One cannot extrapolate the properties of other biogenic amines to p-synephrine based on some structural similarities.”
He added that synephrine was consumed in regular diets via foodstuffs like orange juice, of which a standard glass typically delivered about 20-35 mg of p-synephrine, depending on the variety of orange.
Dr Stohs said he looked forward to, “working with the Finnish Food Safety Authority as you review the current and available scientific literature.”
“As the world’s leading authority on this subject, I shall be happy to respond to any questions that you may have.”