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Title: A biomarker approach for the investigation of the intakes of low-calorie sweeteners
Author: Logue, Caomhan
ISNI:       0000 0004 5993 2558
Awarding Body: Ulster University
Current Institution: Ulster University
Date of Award: 2016
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The use of low-calorie sweeteners (LCSs) has increased considerably over recent decades and can now commonly be found in a wide range of both dietary and non-dietary products. Information on exposure to LCSs is a legislative requirement in the European Union (EU). Furthermore the health effects of LCS consumption remain an area of great scientific interest and therefore a method which assesses intakes more reliably than current methods would be highly desirable. A review of the literature revealed that several LCSs, namely acesulfame-K, saccharin, cyclamate, sucralose and steviol glycosides, may lend themselves well to the application of a urinary biomarker approach for assessing exposure as they are excreted relatively unchanged via the urine. Given that no analytical method has been published for the simultaneous determination of the compounds of interest in urine, a novel liquid chromatography tandem-mass spectrometry method of simultaneously determining acesulfame-K, saccharin, cyclamate, sucralose and the excretory product of steviol glycosides, steviol glucuronide, was developed and validated and shown to be accurate and precise. The analytical method was then used to validate a novel urinary biomarker approach for assessing short-term intakes of the five LCSs of interest. Two studies were conducted with the aims of investigating variation in 24-hour and spot urinary excretion in healthy subjects following a single oral dose containing all of the compounds of interest. A subsequent investigation into the relationship between the candidate biomarkers and the respective LCSs was carried out in a dose-response study where apparently healthy individuals were administered low, medium and high LCS doses relevant to a free-living population. It was shown that both fasting spot and 24-hour urine excretions were capable of distinguishing between low, medium and high intakes of acesulfame-K, saccharin, cyclamate and steviol glycosides while for sucralose, 24-hour urine excretion of sucralose was shown to be sensitive to high and low intakes. These results suggest that using a urinary biomarker approach may be useful for assessing exposure to these commonly consumed LCSs. The final study was carried out in collaboration with the National Institute for Public Health and the Environment, the Netherlands and involved the application of the analytical method to 24-hour urine samples for assessing intakes of the five LCSs of interest within a free-living A biomarker approach for the investigation of the intakes of low-calorie sweeteners Dutch population. Samples were previously collected in 2010 as part of a salt and iodine excretion study and LCS analysis revealed a high prevalence of exposure to multiple LCSs. Interestingly it also revealed that approximately 6% of the study population were exposed to steviol glycosides 12 months before it was approved in the EU, illustrating the usefulness of a biomarker approach for identifying exposure which may not have otherwise been detected. Based on the urinary excretion, intakes within this population were likely to be well within acceptable daily intakes, which is in agreement with previous exposure studies. However the ability to discern intakes of individual LCSs represents a significant advantage over some current research approaches. This thesis presents a novel urinary biomarker approach for the investigation of short-term exposure to five commonly consumed LCSs. The application of such an approach has a number of potential advantages over more traditional methods of monitoring exposure to LCSs which in turn, will enhance research into the health effects of these commonly used food additives.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available