Details of the amendment also requested the deletion of the rule specifying that steviol glycosides contained a minimum of 75% stevioside and/or rebaudiside A.
Rebaudiodside M, also known as rebaudioside X, is a minor steviol glycoside constituent of the Stevia rebaudiana Bertoni (S.rebaudiana) plant.
As part of its assessment the panel evaluated rebaudioside M’s metabolism as well as a comparision with rebaudioside A and stevioside. For rebaudioside A and stevioside there was complete degradation to steviol in the gastrointestinal tract. The steviol produced was absorbed and then metabolised to steviol glucuronide.
To further assess its profile a series of in vitro metabolism studies were conducted to assess individual steviol glycosides at concentrations of 0.2mg and 2mg/mL for up to 48 hours.
“The panel considered that the steviol exposure from an equivalent dose of rebaudioside D and M could be estimated and that considering the common degradation steps their safety profile could be evaluated on the same basis as stevioside and rebaudioside A,” the report stated.
The panel went on to look at the rate and degree of microbial hydroloysis to confirm the plausibility of this hypothesis.
The panel accepted the toxicological studies performed with stevioside and rebaudioside A were relevant for assessing the safety of any steviol glycoside degraded in the intestine.
Provided the total amount of steviol glycosides (stevioside; rebaudioside; A, B, C, D, E, F and M; steviolbioside; rubusoside; and dulcoside) were greater than 95% and were all converted to steviol, the food additive would not pose a safety concern. This assumed that there was no evidence of absorption for intact glycosides at realistic use levels.
The panel concluded that the Acceptable Daily Intake (ADI) of 4mg/kg bw/day could also be applied where steviol glucosides made up more than 95% of the material.
EFSA evaluated the safety of steviol glycosides as a sweetener in 2010 based its conclusions on the conversion to steviol in the intestine and that steviol was the only compound systemically available.
Several assessments have since been made for stevioside as a sweetener by the Scientific Committee for Food, the Joint FAO/WHO Expert Committee for Food (SCF in 1984-1999), the Joint FAO/WHO Expert Committee on Food Additives (JECFA in 2000-2010 time frame) as well as EFSA (2010-2015).