The effects of caffeine and co-consumed ingredients on human performance (Ref: RDFC24/HLS/PSY/WIGHTMAN)

Caffeine induces well-established effects on human performance. Low (~40 mg) and moderate (~300 mg) doses of caffeine reliably and robustly improve alertness, vigilance, attention and reaction time and the primary mechanism attributed to these effects is the inhibition of the neuromodulator adenosine, by blockade of A1 and A2a adenosine receptors. As caffeine has been observed to reach peak plasma concentrations within 1 hour of oral ingestion, these effects on cognitive function are observable within 30-60 minutes after consumption, with some inter-individual variability and differences observed depending on the caffeine-containing product and co-consumed ingredients (see McLellan et al., 2016 for review).

However, in naturalistic settings, caffeine is rarely consumed in isolation, and yet we know very little about how the effects of caffeine are affected by co-consumed ingredients. We know that naturally co-existing ingredients (i.e. those which exist alongside caffeine within the plant, and translate into the same product, like tea and coffee) can ameliorate the effects of caffeine when consumed at the same time. L-theanine, for example, can reduce the ‘jitteriness’ associated with caffeine alone and chlorogenic acid can attenuate caffeine-induced anxiety (Schuster & Mitchell, 2019). However, caffeine products developed from plants will also contain a whole plethora of micro-, macro-nutrients and botanical compounds which have probably historically been omitted from research so that the clear effects of caffeine alone could be understood. However, this is not how most people consume caffeine on a daily basis and this limits the extent to which we can extrapolate these historical findings.

The current programme of research aims to redress this by investigating the effects of caffeine, alongside co-consumed ingredients, on human performance. The initial study will focus on cognitive function and future trials will develop from this to incorporate other aspects of human health and wellbeing.

This PhD will be supervised by colleagues within Nutrition Trials At Northumbria (NUTRAN); an interdisciplinary research group with a mission to improve health and wellbeing utilizing nutrition. Emma and Sarah are based within the psychology department, and Iain is based in Applied Sciences. It is anticipated that the first trial of this PhD programme will be a large-scale assessment of cognitive function in the form of a randomised controlled trial. Subsequent trials are expected to be more interdisciplinary, and may require the student to extract and process biological samples (e.g. taking blood samples and using assay kits) as well as utilize appropriate techniques, like assessment of blood flow. Training will be provided on all such processes. Given the interdisciplinary nature of the PhD programme, it is anticipated that the student could have studied either Psychology or Applied Sciences (or similar) degrees, but experience in managing human trials would be desirable. If unsure about your experience, please contact [email protected].

Academic Enquiries

This project is supervised by Dr Emma Wightman, Dr Sarah Docherty and Dr Iain Brownlee. For informal queries, please contact [email protected]. For all other enquiries relating to eligibility or application process please use the email form below to contact Admissions. 

Eligibility Requirements:

•         Academic excellence i.e. 2:1 (or equivalent GPA from non-UK universities with preference for 1st class honours); or a Masters (preference for Merit or above); or APEL evidence of substantial practitioner achievement.

•         Appropriate IELTS score, if required.

•         Applicants cannot apply if they are already a PhD holder or if currently engaged in Doctoral study at Northumbria or elsewhere.

To be classed as a Home student, candidates must:

•         Be a UK National (meeting residency requirements), or

•         have settled status, or

•         have pre-settled status (meeting residency requirements), or

•         have indefinite leave to remain or enter.

If a candidate does not meet the criteria above, they would be classed as an International student.  

Applicants will need to be in the UK and fully enrolled before stipend payments can commence.

For further details on how to apply see

https://www.northumbria.ac.uk/research/postgraduate-research-degrees/how-to-apply/   

In your application, please include a research proposal of approximately 1,000 words and the advert reference (RDFC24/HLS/PSY/WIGHTMAN)

Deadline for applications: 31 July 2024

Start date of course: 1 October 2024

Northumbria University is committed to creating an inclusive culture where we take pride in, and value, the diversity of our postgraduate research students. We encourage and welcome applications from all members of the community. The University holds a bronze Athena Swan award in recognition of our commitment to advancing gender equality, we are a Disability Confident Leader, a member of the Race Equality Charter and are participating in the Stonewall Diversity Champion Programme. We also hold the HR Excellence in Research award for implementing the concordat supporting the career Development of Researchers and are members of the Euraxess initiative to deliver information and support to professional researchers.