PhD Study : An investigation of the impact of low-calorie sweeteners on obesity and glucose metabolism

Summary

Obesity and type 2 diabetes represent major health concerns globally (World Health Organisation (WHO), 2016; Bluher, 2019) and recent UK public health recommendations have focused on limiting free sugars consumption to 5-10% of total daily energy intake (Scientific Advisory Committee on Nutrition (SACN), 2015). A key component of sugar reduction strategies is product reformulation, i.e. replacing free sugars with low-calorie sweeteners (LCS) (Public Health England (PHE), 2017). This is likely to result in increased use of LCS, which is already widespread. LCS are often used to reduce the energy density of the diet without compromising on palatability and, whilst experimental data tends to support the case for a beneficial effect of LCS on energy intake, evidence from free-living populations is less clear (Rogers et al., 2016).

The lack of scientific consensus around the efficacy of LCS for promoting human health has led to research into potential mechanisms by which they may impact body weight and/or glucose metabolism. These potential mechanisms include altered taste preferences, metabolic effects, and interactions with the gut microbiota (Burke and Small, 2015) albeit no specific mechanism has been conclusively established. Therefore, the overarching aim of this project is to investigate the relationship between LCS and human health with a view to exploring specific mechanisms related to body weight regulation and glucose metabolism.

Specific project objectives are:

• To investigate the effect of LCS on markers of glucose metabolism and appetite regulation.
• To investigate the effect of LCS on behavioural factors related to body weight regulation.

The proposed project will build upon previous work undertaken at Ulster. To date, a novel urinary biomarker approach has been developed (Logue et al., 2017) and applied to reveal widespread exposure to multiple LCS in free-living populations (Logue et al., 2020). Such findings have highlighted important gaps in the literature, which need to be addressed to help inform strategies aimed at preventing and managing unintentional weight gain (overweight and obesity) as well as in the prevention and management of diabetes mellitus.

Proposed Methods

The project will initially involve a systematic review of the literature to inform in vitro and in vivo research into the impact of LCS on body weight status, dietary behaviours, and gut hormone release in various models. A targeted approach will be used to assess whether specific combinations of LCS impact glucose metabolism, gut hormone release (GLP-1, GIP) as well as food choice and energy consumption at physiologically relevant concentrations. Other factors related to dietary behaviours such as relative food preferences and sensory characteristics will also be considered. This project will address some important limitations of existing research by investigating LCS in a way that is reflective of actual use i.e. in combinations rather than in isolation and at concentrations observed in the diet.

The successful candidate will work with an experienced and varied supervisory team to gain experience in a range of scientific methods.

They will also get the opportunity to present their findings at national and international scientific conferences.

AccessNI clearance required

Please note, the successful candidate will be required to obtain AccessNI clearance prior to registration due to the nature of the project.

Essential criteria

Applicants should hold, or expect to obtain, a First or Upper Second Class Honours Degree in a subject relevant to the proposed area of study.

We may also consider applications from those who hold equivalent qualifications, for example, a Lower Second Class Honours Degree plus a Master’s Degree with Distinction.

In exceptional circumstances, the University may consider a portfolio of evidence from applicants who have appropriate professional experience which is equivalent to the learning outcomes of an Honours degree in lieu of academic qualifications.

• Sound understanding of subject area as evidenced by a comprehensive research proposal
• Clearly defined research proposal detailing background, research questions, aims and methodology

Desirable Criteria

If the University receives a large number of applicants for the project, the following desirable criteria may be applied to shortlist applicants for interview.

• Completion of Masters at a level equivalent to commendation or distinction at Ulster
• Experience using research methods or other approaches relevant to the subject domain
• Sound understanding of subject area as evidenced by a comprehensive research proposal
• Work experience relevant to the proposed project
• Publications record appropriate to career stage
• Experience of presentation of research findings
• A comprehensive and articulate personal statement
• Relevant professional qualification and/or a Degree in a Health or Health related area

Funding and eligibility

The University offers the following levels of support:

Vice Chancellors Research Studentship (VCRS)

The following scholarship options are available to applicants worldwide:

• Full Award: (full-time tuition fees + £19,000 (tbc))
• Part Award: (full-time tuition fees + £9,500)
• Fees Only Award: (full-time tuition fees)

These scholarships will cover full-time PhD tuition fees for three years (subject to satisfactory academic performance) and will provide a £900 per annum research training support grant (RTSG) to help support the PhD researcher.

Applicants who already hold a doctoral degree or who have been registered on a programme of research leading to the award of a doctoral degree on a full-time basis for more than one year (or part-time equivalent) are NOT eligible to apply for an award.

Please note: you will automatically be entered into the competition for the Full Award, unless you state otherwise in your application.

Department for the Economy (DFE)

The scholarship will cover tuition fees at the Home rate and a maintenance allowance of £19,000 (tbc) per annum for three years (subject to satisfactory academic performance).

This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

• Candidates with pre-settled or settled status under the EU Settlement Scheme, who also satisfy a three year residency requirement in the UK prior to the start of the course for which a Studentship is held MAY receive a Studentship covering fees and maintenance.
• Republic of Ireland (ROI) nationals who satisfy three years’ residency in the UK prior to the start of the course MAY receive a Studentship covering fees and maintenance (ROI nationals don’t need to have pre-settled or settled status under the EU Settlement Scheme to qualify).
• Other non-ROI EU applicants are ‘International’ are not eligible for this source of funding.
• Applicants who already hold a doctoral degree or who have been registered on a programme of research leading to the award of a doctoral degree on a full-time basis for more than one year (or part-time equivalent) are NOT eligible to apply for an award.

Due consideration should be given to financing your studies. Further information on cost of living