Frequently Asked Questions

Why is the study needed?

·       The gut microbiota is the group of microorganisms (very small living things, such as bacteria and fungi) that live inside and on the surface of our digestive system (e.g. gut, colon, intestines). 

·       It is estimated to outnumber our own cells by 10 times and combines over a hundred times more genes than the human genome. 

·       These microorganisms are known to perform useful functions, such as fermenting food material, producing vitamins, and preventing growth of pathogens (harmful organisms). 

·       There is also evidence that some bacteria can produce neurotransmitters (chemical messengers) such as serotonin and GABA (Gamma Amino Butyric Acid). 

·       Some studies have associated abnormalities of the microbiota composition with metabolic disorders, such as inflammatory bowel disease and obesity, as well as psychiatric conditions, such as depression and anxiety. 

·       The research in this field is still in its early days and is therefore very active.

What does taking part in the study involve?

Before you can take part in the study, you will be asked to:

·       Complete an online questionnaire to assess whether you meet the study inclusion criteria.

·       Attend a 30-minute screening visit. The screening visit can be done online or in person at the University of Reading. 


If you meet the eligibility criteria and are happy to participate, you will be invited to take part in the study at the University of Reading. Taking part in the study would involve you:

·       Completing an online food and drink questionnaire 

·       Providing a urine sample 

·       Providing a faecal sample

·       Having a small blood sample taken. This would be 9-millilitres (ml). 

·       Having body composition measures taken. These include your height, weight, and body fat percentage.

·       Having blood pressure readings taken

·       Undergoing a 1-hour Magnetic Resonance Imaging (MRI) scan of your brain 

·       Completing three computer tasks

·       Completing questionnaires 

The initial screening questionnaire, screening visit, and study appointments are explained in further detail below. 


The study involves two different streams, which we refer to as Work Package 1 (WP1) and Work Package 2 (WP2). You can choose which of these you would prefer, or which would suit your schedule better. These are explained in more detail below.

Work Package 1 (WP1) is an observational (single-visit) study aimed at evaluating the baseline gut microbiota composition and its association with individual differences in brain and behavioural functioning. WP1 involves one study appointment (+ screening visit). 


Work Package 2 (WP2) is a double-blind interventional cross-over (multi-visit) study which assesses the effects of a dietary intervention (probiotic) on gut microbiota composition and its association with individual differences in brain and behavioural functioning. WP2 involves four study appointments (+ screening visit) spread over 12 weeks, with approximately 28 days between study appointments:
- Study appointment 1 (Week 0)
- Study appointment 2 (Week 4)
- Study appointment 3 (Week 8)
- Study appointment 4 (Week 12).

What is the difference between Work Package 1 (WP1) and Work Package 2 (WP2)?

Work package 1 (WP1) is aimed at evaluating the relationship between baseline gut microbiota composition and individual differences in brain functioning, behaviour and personality traits. 

Work package 2 (WP2) involves a dietary intervention that will contain probiotics and a placebo. 

The key differences between WP1 and WP2 are therefore:

·       Time commitment: WP1 is a single-visit study, whereas WP2 involves multiple (4) visits to the University of Reading. 

·       Dietary intervention: If you would like to take part in WP2, you will be asked to take a dietary intervention consisting of a probiotic and placebo for 28-40 days at two different timepoints. 

Please note that we are no longer recruiting volunteers for Work Package 2. 

If you would like to take part in the study, Work Package 1 is still available. 

Please follow this link to see if you are eligible.

What do you mean by MRI?

·       Magnetic Resonance Imaging (MRI) is an imaging technique that uses a strong magnetic field and radiofrequency electromagnetic waves (similar to radio and television waves) to “excite” hydrogen molecules in the body. 

·       The MRI scanner measures small changes in magnetic fields produced in your brain and uses these to generate different images. 

·       During your MRI scan, you will be asked to lie down on the scanner bed and a plastic coil will be placed around the top part of your head. 

·       We will attach a belt around your waist (over your shirt), and a pulse monitor to one of your fingers. Breathing generates even the tiniest movements, which can affect the MRI data we collect. In addition, everyone breathes differently. We therefore attach the belt and pulse monitor so that we can use this information later when it comes to analysing the data.

·       Foam pads will be placed between your head and the coil to limit head movement during the study. 

·       You will then be moved into the bore of the magnet and asked to lie still for approximately 60 minutes, during which time MRI images will be acquired.

What do you mean by faecal sample? How will this be collected?

·       By ‘faecal’, we refer to a sample of your poo/stool. 

·       We will ask participants to collect a faecal sample at home on the morning of your study appointment(s) using a kit we provide you with. 

·       We realise that everybody’s bowel movements are slightly different and nature calls at different times. Therefore, if you’re not able to produce your faecal sample the day of your study appointment, you will have the option of brining the sample to the University of Reading within 3 days of your study appointment. 

What do you mean by urine sample? How will this be collected?

·       By ‘urine’, we refer to a sample of your pee.

·       We will ask participants to provide a spot urine sample, which is your first morning urine. You’ll be asked to collect your first urine of the morning at home using a kit we provide you with. 

What do you mean by blood sample? How will this be collected?

·       By blood sample we refer to a venous blood sample, which is taken from your inner elbow.

·       The blood sample will be drawn by a trained and experienced phlebotomist during your study appointment(s) at the University of Reading. You will be asked to lie down, and we will take about 9 millilitres in one single tube. We will provide you with some snacks and water to make sure you’re feeling comfortable. 

·       Please note that you will not have to fast for your blood sample to be taken. We do recommend that you stay well hydrated before your study appointment(s) as this will help us draw your blood sample smoothly.

What are the supplements I will be asked to take?

Please note you will only be provided with supplements if you are participating in WP2. This section is not relevant for volunteers taking part in WP1. 

You will be given both a probiotic and a placebo supplement at different timepoints. 

·       Probiotics are live microorganisms that are beneficial to your health when administered in adequate amounts. Probiotic bacteria are found in a variety of different products, including foods, dietary supplements, infant formulas and pharmaceuticals (e.g., Yakult yogurt).

·       A placebo has no therapeutic value and is used so that we can test the effectiveness of the probiotic.

Everyone who agrees to take part in WP2 will be put into a treatment arm


As the study is double-blinded, neither you nor the researchers will know which supplement is which. We simply refer to them as supplement A and supplement B. This means that both supplement A and supplement B have an equal chance of being the probiotic or placebo, and we do not know which is which. This is to reduce any bias

WP2 will have two arms: AB and BA. These arms refer to the order in which you will receive the supplements. For example, if you are assigned to arm AB, you will be given supplement A to take between your first and second study appointments. You will then be given supplement B to take between your third and fourth study appointments. Alternatively, if you are assigned to arm BA, you will be given supplement B to take between your first and second study appointments. You will then be given supplement A to take between your third and fourth study appointments. You will be assigned to arm AB or BA through a process called randomisation, which means you cannot choose which arm you will be assigned to. You and the study researchers will know which study arm you are placed in, but not which supplement is which. 

The supplements you receive will be in capsule form. You will be asked to take one capsule daily, preferably with breakfast or another meal that you eat regularly. We will send you reminders via email every week to help you remember to take the supplement. 

Please note that we are no longer recruiting volunteers for Work Package 2. 

If you would like to take part in the study, Work Package 1 is still available. 

Please follow this link to see if you are eligible.

Am I eligible to take part?

Study inclusion criteria

You are eligible to take part in the study if you:

·       Are male.

·       Are aged between 18 and 50. 

·       Are White Caucasian.

·       Grew up in the UK or other European country.

·       Have a body mass index (BMI) between 18.5 and 30.

·       Are right-handed.

Study exclusion criteria

You are not eligible to take part in the study if you:

·       Have taken antibiotics in the last 3 months. 

·       Have used a protonic pump inhibitor (PPI, e.g. omeprazole, lansoprazole) in the last 3 months.

·       Are a current smoker, or have a history of regular smoking within the last 6 months.

·       Regularly drink more than 14 units of alcohol per week.

·       Use drugs acting on the brain for medical or recreational purposes.

·       Use probiotic/prebiotic supplements.

·       Have a current clinical diagnosis of a neurological, developmental, or psychiatric condition. 

·       Have a current diagnosis or history of gut microbiota related conditions, such as inflammatory bowel disease or irritable bowel syndrome. 

·       Have any MRI contraindications that would prevent you from being safely scanned for research purposes. 


The reason for these inclusion and exclusion criteria is that several factors, such as gender, ethnicity, or use of alcohol or drugs acting on the brain, can have a big effect on gut microbial composition and can change performance in the computer tasks you will be asked to do. Exclusion on the basis of MRI contraindications is for your general health and safety.

What MRI contraindications would prevent me from being eligible for the study?

For a very small number of individuals, undergoing an MRI can endanger comfort, health, or even life. Specifically, the Department of Health advises that certain people should not be scanned. 


You would not be eligible to participate if you: 

·       Have a pacemaker or artificial heart valve

·       Have any active implants (e.g. cochlear, ocular, or penile implant)

·       Have ever had metal fragments in your eyes

·       Have ever had any metal fragments, e.g. shrapnel, in any other part of your body

·       Have a drug infusion pump installed

·       Have any stimulators for nerves, brain or bone installed

·       May be pregnant

·       Have ever been diagnosed with any form of heart disease or thermoregulatory problem

·       Have any surgically implanted metal in any part of your body, other than dental fillings and crowns (e.g. joint replacement or bone re-construction)

·       Have ever had any surgery that may have involved metal implants

·       Have ever suffered from epilepsy

·       Have an intrauterine contraceptive device installed

·       Have any body piercings that you cannot or are unwilling to remove


In addition to the above, there are further criteria that may prevent you from being safely scanned for research purposes


You may not be eligible if you:

·       Wear transdermal patches that contain metal

·       Wear a filling, crown, dental post (entirely within the tooth) associated with root canal treatment, retainer, bridge, or braces

·       Use coloured contact lenses

·       Wear a hearing aid

·       Have any tattoos or permanent make-up

·       Are claustrophobic


Although you may have any of the above contraindications and have had an MRI in a clinical setting, we may not agree to scan you for research purposes. We will respond to each of these on a case by case basis.  

Do I have to take part?

·       No, it is completely up to you. Taking part in this study is completely voluntary.

·       You are free to withdraw from the study at any time, without giving a reason.

What should I do if I want to take part?

If you would like to join the study, please complete the initial screening questionnaire online here.

The questionnaire will take between 5-15 minutes to complete, depending on your answers to the questions. 


You can expect to be asked questions on the following topics:

·       Contact details 

·       Demographic information

·       Study requirements

·       MRI safety screening

·       Medical and lifestyle information 

·       Whether you have a preference for WP1 or WP2


Your responses to questions relating to the above topics will help us to:

·       Confirm whether you are happy to meet the study requirements

·       Assess whether you meet the study inclusion criteria

·       Confirm whether it is safe for you to have an MRI scan

·       Check whether there is any reason you would not be eligible to participate

·       inform you of your eligibility 

·       Schedule your appointments

What happens after the initial screening questionnaire?

·       Once we have received and reviewed your completed initial screening questionnaire, we will send you a further email to let you know if you are eligible. 

·       Please note that depending on your answers to the initial screening questionnaire, you may be informed directly through the questionnaire if you are not eligible to participate immediately. 

·       Otherwise, we will contact you within a couple of working days via email to let you know if you can participate in the study.

I found out I am eligible to participate in the study. What happens next?

·       If you are eligible, we will send you a link to a short online questionnaire with the purpose of scheduling your screening visit and study appointment. 

·       You will be able to choose from a list of available study appointments or to request dates and times that are not listed. Our team will do our best to accommodate you wherever possible. 

·       Once we have booked you in for your appointments, you will receive calendar invitations as well as an email confirming the appointments. 

·       You will also receive an email reminding you of your screening visit and study appointment(s) approximately 24 hours before you are due to see us. These emails will contain information telling you exactly where you will have to go and what you will need to bring. 

What happens during the screening visit?

Sometime before your study appointment, we will invite you to the University of Reading to attend a screening visit, which will last approximately 30 minutes. The screening visit is a great opportunity to meet the researchers involved in the study, and most of all to ask any questions you may have. 


You can expect to be provided with the same information as in this document, but in a little more depth. For example:

·       You will be told about why we are doing the study and what the study appointment involves. 

·       We will explain the difference between WP1 and WP2 and double check if you have a preference for either of these. 

·       We will talk you through the sample kit and explain what each item in the kit is for, and how we recommend for you to collect your urine and faecal samples at home. 

·       You will be told a little more about how you can complete the food and drink questionnaire ahead of your study appointment. 


If you are happy to participate, we will go through the general study consent form with you, as well as the MRI consent and initial screening form.


If there is any information that we need to clarify with you to double check your eligibility, you can expect us to ask you about this at this point.


If you are interested in taking part in WP2, we will suggest some dates for your follow-up visits (study appointments 2, 3, and 4).


After the screening visit, we will email you a copy of your consent form. If you are taking part in WP2, we will also schedule your follow-up appointments and send you calendar invitations for those. 


Please note that it is possible for the screening visit to be done online if you are not able to travel to the university. In this case we can post the sample kit out to your preferred address. 

What happens during the study appointment(s)?

For your study appointment, you will be asked to complete an online food and drink questionnaire, and to collect your faecal and urine samples at home. 

Once you arrive at the Harry Nursten Building / Hugh Sinclair Unit, we will relieve you of your samples, take some body composition measures, and a small blood sample. 

Following this, we will ask you to make your way to the Harry Pitt Building / School of Psychology and Clinical Language Sciences, where your MRI scan and computer tasks will take place. 

The overall study appointment should last approximately 3 hours, and is described in more detail below. 

Before arriving on the day of your study appointment

·       Complete food and drink questionnaire. You will receive instructions on how to complete the food and drink questionnaire using the eNutri platform before your study appointment. Please ensure you complete this on the day of your study appointment, or the day before if you have some spare time.

·       Collect urine and faecal samples. Please collect your urine and faecal samples using the sample kit and instructions provided. We ask that you provide the first urine of the morning, and as fresh a faecal sample as possible. Please use the ice pack we provide to keep your samples fresh. 

At the Harry Nursten Building/Hugh Sinclair Unit

·       Hand over your samples to one of the researchers. We will relieve you of your samples when you arrive. 

·       Body composition measures. One of our researchers will take your height, weight, and measure your body fat percentage. You will be asked to remove your shoes and socks. 

·       Blood pressure readings. We will take three measures of your blood pressure to obtain an average of your readings. 

·       Blood sample collection. One of our trained phlebotomists will collect a small blood sample of 9 millilitres (ml) in a single tube. 

At the Harry Pitt Building/ School of Psychology and Clinical Language Sciences

·       MRI safety forms and MRI scan. We will go through some health and safety forms with you to double check it is safe for you to be scanned. As the MRI scanner is loud, we will give you some earplugs to minimise any noise. You’ll be given an emergency buzzer to squeeze in case you feel uncomfortable at any point. We will also attach a belt around your waist (over your shirt) and a pulse monitor to one of your fingers. This is because everyone breathes differently, and we will take this into account when analysing the data at a later stage. You will be in the MRI scanner for about an hour, and will undergo a series of short scans, which are 8-15 minutes long each. We will talk to you through the intercom in between scans to make sure you are comfortable. 

·       Computer tasks and questionnaires. We’ll head to a computer room where you will carry out some computer tasks and complete questionnaires. The tasks that you will be invited to carry out will include watching stimuli (e.g., emotional faces or patterns) on a computer screen and making simple judgments on them using the computer keyboard. It will also involve a test of sensory abilities, where you will be asked to make simple judgments on tactile stimuli in the form of a vibration (which feels similar to the vibration felt on a mobile phone when receiving a message). We will finally ask you to complete some questionnaires on the computer. These will include a series of statements, and you’ll be asked to select the extent to which you agree or disagree with each statement. 

If you are taking part in Work Package 1 (single-visit study), we will also ask you to complete a payment form at this point. This would mark the end of your participation!

Alternatively, taking part in Work Package 2 would involve all the above but at three additional time points (i.e. four study appointments in total). For WP2 you would also be asked to take a probiotic and/or placebo supplement between appointments 1 and 2, and appointments 3 and 4.

Are there any benefits for me in joining the study?

·       Participating in the study will benefit the development of research and give you an idea of how research is conducted. 

·       We are also happy to pay you for your time. 

o   You will be paid £50 for participating in WP1. 

o   For WP2, you will be paid £50 per study appointment, i.e., £200. We will also offer a £50 bonus to participants who complete all four WP2 study appointments. 

·       The first 100 miles of travel expenses you incur getting to and from your screening visit and study appointment(s) will be reimbursed.  This means that if you are driving, we will reimburse you for the first 100 miles of each separate journey (both to and from appointments) only. If you are travelling by train, we will reimburse you for a ticket to and from the train station along your route of travel that is closest to 100 miles from the University of Reading.

·       At the end of your participation, we will also send you a high-resolution image of a structural scan of your brain. 

Please note that we are no longer recruiting volunteers for Work Package 2. 

If you would like to take part in the study, Work Package 1 is still available. 

Please follow this link to see if you are eligible.

How will I be reimbursed?

·       You will be paid via bank transfer following the end of your participation in the study. 

·       At your last study appointment (first and only study appointment if WP1, fourth and final study appointment if WP2), we will ask you to complete a volunteer payment form. We will ask for your bank details (account number, sort code, and address), and will total up your reimbursement for participation plus any travel costs you have incurred. 

·       We will then forward the information to our departmental finance team, who will arrange the payment for you. You should receive payment within a month of your final appointment. 

·       Please hold on to any physical receipts (e.g., train tickets) and give these to the study researchers to create copies. Alternatively, if you have any electronic receipts, please forward them to

·       If you drive, we will need some information about your car to reimburse you for fuel. This includes your car engine size, fuel type (petrol or diesel), and how many miles you have covered getting to and from each appointment. 

·       If you are taking part in WP2, we will keep a log of your travel expenses so that they can be totalled and paid together with your reimbursement at the end of your participation. 

·      If you withdraw from the study for any reason, we will pay you up to the point of your last study appointment. For example, if you take part in WP2 and withdraw after your second study appointment, you will receive £100 plus any travel costs incurred. 

Please note that we are no longer recruiting volunteers for Work Package 2. 

If you would like to take part in the study, Work Package 1 is still available. 

Please follow this link to see if you are eligible.

Are there any risks for me in joining the study?

There are minimal risks involved in participating in the study. However, we have identified some risks that full under the following categories: 

1)    MRI, 

2)    Faecal and urine samples

3)    Blood sample collection

4)    Dietary supplements

5)    COVID-19


·       MRI scanning itself is painless. Nevertheless, you may experience some discomfort, including from mechanical noise made when the scanner is collecting measurements. You will be provided with earplugs to minimise the impact of this noise. 

·       The bore of the MRI scanner is large enough to fit an adult but may feel small to some people. Individuals with a history of claustrophobia should not take part in the study. If you wish to interrupt the MRI scan at any time due to feelings of distress, you will have the ability to do so. 

·       This study is part of a research protocol and is not intended to provide a comprehensive clinical MRI examination of the brain. Your MRI scan will not be read by a radiologist. However, if a potential abnormality is identified on your MRI scan, a copy of the image will be sent first to a radiologist for advice, then, if advised by the radiologist, to your GP. By signing the consent form, you authorise us to do this. If you are not willing to authorise this, please do not volunteer for the study. 

Faecal and urine samples

·       The results obtained by analysing faecal and urine samples will only be aimed at assessing the quantity of specific metabolites relevant to our study, and will not have any health relevance. 

·       This research study has no medical or diagnostic purposes, and is not aimed to produce medical information or to provide health-related advice. 

·       However, if we were to detect any deviations of your gut microbiome from the population average, we would let you know. 

Blood sample collection

·       Your blood sample will be drawn by a trained phlebotomist at the University of Reading.

·       Although having blood taken can be slightly painful, it is usually well tolerated.

·       A small amount of blood (9 ml) will be taken. This means you should not feel any significant after-effects. 

·       Some people may experience dizziness or feel faint after having their blood drawn. We will ask you to lie on a bed while the blood sample is collected and will provide you with snacks and beverages after your blood sample has been taken to help you feel more comfortable.

·       Some people may also have a small bruise where the needle was inserted during blood sample collection. Although bruises can be painful, they are usually harmless and fade over the next few days. 

·       If having a blood sample taken will cause you extreme distress, e.g., due to needle phobia, it will be possible for you to take part in the study without providing a blood sample. 

Dietary supplements

·       If you agree to participate in Work Package 2, you will be asked to take a probiotic for 4 weeks and placebo for 4 weeks.  Both you and the researchers will not be aware of which dietary intervention you will be asked to take first.

·       Participation in the dietary intervention should not pose any significant risk.

·       The placebo we use is called maltodextrin. It is a standard placebo product for use in human studies and has been used safely at this dose, in many trials over the last 20 years. 

·       The probiotics, and possible associated prebiotics, will be selected from available off-the-shelf supplements, which have been deemed acceptable for the market and are therefore safe to take regularly. 

·       Probiotics are safe for human consumption. These microorganisms have been previously tested and shown to provide a health benefit. However, some people could report an increase in gas production, with slight bloating, flatulence and mild diarrhoea. Such cases are very rare. As such, to minimise symptoms it will be recommended that volunteers take probiotics at the same time as a meal. 


·       In consideration of the global COVID-19 pandemic, we will take applicable local measures to reduce any risks of transmission related to attending the University of Reading for your visits. 

·       For example, you may be asked to wear a face mask. We will provide you with a face mask in these cases.

How do I withdraw if I want to do so?

·       The study will be most valuable if few people withdraw from it, so it is important to discuss any concerns you have with a member of the study team before you agree to participate. 

·       However, you can withdraw from the study at any time and without giving a reason. 

·       You can withdraw by emailing

What data will you collect from me and how will my data be kept?

We will always protect your privacy and ensure that your data is handled in accordance with the General Data Protection Regulation (GDPR) (EU) 2016/679.


·       Personal data. If you agree to take part in the study, we will collect some data about you. Specifically, we will collect some information about your age, diet, ethnicity, physical and mental health to evaluate if you meet the inclusion criteria for our study. We will also collect some identifying information (name, telephone and email contacts). This information will allow us to get in contact with you when needed (i.e., organising study visits). 

·       Research data. During the study we will collect and analyse your faecal, blood and urine samples, and we will collect data about your performance in the above- mentioned behavioural tasks. We will also collect and analyse images of your brain from the MRI scans. 

·       eNutri data. During the study, you will be asked to complete food and drink questionnaires using the eNutri platform.

Personal data

·       Your personal data will be kept confidential and securely stored for five years, in a coded form, whereby data and observations will be linked to the personally identifiable information only through a code available only to the Principal Investigator of the study. 

·       Information linking that number to your name will be stored securely and separately from the data you provide us. 

·       All personally identifiable information collected for the project will be stored for five years and destroyed thereafter. 

·       Should you have questions about how your personal data is managed, you can contact the University Data Protection Officer at:

Research data

·       The anonymised data collected during the study will be analysed and the results of our study will appear in scientific publications. 

·       At the end of the project, all the data will be preserved and made available in anonymised form (on e.g., University of Reading’s Research Data Archive and OpenNeuro), so that they can be consulted and re-used by others.

eNutri data

·       Until the end of the study, all data entered on eNutri will be temporarily stored by the password- protected Google Firebase technology (a reliable and widely-used platform developed by Google for creating mobile and web applications). 

·       It is certified under major privacy and security standards and complies with requirements under GDPR in connection with the transfer of personal data from the United Kingdom (UK) and European Union (EU) to the United States (US) (data may be processed in other countries including the US). 

·       Data transferred between your web browser and Google Firebase is encrypted (i.e., it is hidden from or inaccessible to anyone outside of the research team). 

·       When you use eNutri, your data is pseudonymised (i.e., linked to your unique eNutri ID code, not your name so you will not be personally identifiable). 

·       Your eNutri data will be accessible to the University of Reading’s eNutri Research Team (led by Professor Julie Lovegrove), who will use this data for further research. 

·       Since data sharing is important within the scientific community, your fully anonymised/unidentifiable eNutri data (without names or ID codes) will be made available on a data repository for other researchers to conduct further research. 

What happens to the results of the study?

At the end of the study the information collected will be analysed and published in recognised research journals. The identity of the participants who took part in the study will remain confidential. 

A summary of our findings will be sent to each volunteer who expresses a willingness to be informed about the results. 

Can I know the results obtained from my faecal, urine and blood samples, or from my MRI?

Your biological samples (faecal, urine and blood samples) will be analysed in batches together with those of other volunteers. As this is a large study and will take several years to complete, your samples may not be analysed for quite some time. We are therefore not able to provide you with individualised results obtained from your faecal, urine and blood samples. When we process the samples, we may notice if they look different to those in normal population. In this case we would let you know, and if appropriate, will advise you to contact your GP. 

Your MRI scans will not be read by a radiologist, and the study researchers are not medically trained to notice any abnormalities in your scans. However, should we notice anything that may be of concern, we would send your scans to a radiologist. 

Who is organising and funding the study?

This study has been set up by the University of Reading and has been funded by the European Research Council (ERC). 

Who has approved the study?

All research in the NHS is reviewed by an independent group of people, called a Research Ethics Committee which is there to protect your safety, rights, wellbeing and dignity. This project has been reviewed and was given a favourable opinion by the NHS Wales Research Ethics Committee 4 Wrexham (23/WA/0042).

Who do I contact if I have any concerns?

·       If you have any concerns or complaints about anything to do with the study, please reach out to us via email at

·       Alternatively, if you would like to write to the principal investigator, please send your letter to:

Professor Bhismadev Chakrabarti

School of Psychology and Clinical Language Sciences

University of Reading





Can I be removed from the study?

It is unlikely but possible that you could be removed from the study. 


The reasons you may be removed from the study are as follows:

·       Continuous non-compliance to the outlined study protocols. For example, this includes not providing required samples or using the provided sample kit, not being willing to undergo an MRI or to complete computers tasks and questionnaires, not completing eNutri. 

·       Change in lifestyle or medical circumstances. This includes taking up lifestyle changes that mean you no longer meet the study inclusion criteria, e.g., smoking, taking recreational/psychotropic drugs or probiotics. In addition, any changes in medical circumstances that involve use of antibiotics, PPIs, or diagnoses of neurological, developmental, psychiatric, or gut microbiota-related conditions. 

·       Any risk or danger to the study researchers.

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