A randomized, double-blind, placebo-controlled trial evaluating the influence of a concentrated phytochemical rich food capsule and a probiotic capsule on clinical outcomes among individuals with covid-19 viral infection


Participant Information

You have been invited to take part in a clinical trial by the doctors and the research team at Bedford Hospital, one of the hospitals within Bedfordshire Hospitals NHS Foundation Trust. Before agreeing to take part, you should know exactly what taking part will mean to you, and what you are required to do. This Participant Information Sheet supports the verbal explanation given to you by your doctor and research nurse or practitioner. This trial has been approved by the National Research Ethics Committee (Sheffield Committee, approval number: 20/YH/0164) and has been sponsored by Bedfordshire Hospitals NHS Foundation Trust.

Why have I been invited to take part in this study? You have been asked to consider participating in this clinical trial because you have had a positive Covid-19 swab or developed symptoms of the covid-19 infection such as breathlessness, fatigue, cough, loss of taste or smell, or a raised temperature.

What is the study trying to find out? This study is trying to find out if a whole-food supplement, rich in natural plant-based chemicals (phytochemicals), could shorten recovery time and reduce complications from a Covid-19 (Coronavirus) infection. The best way of finding out if the whole-food supplement is making a difference is to do a randomised trial of the food supplement verses a placebo or dummy supplement. This will be discussed in more detail later on in this leaflet, but in this study you will have a 50% chance of being randomly selected to receive the food supplement capsule, or receiving a placebo (dummy) supplement. Regardless of whether you are randomised to the food supplement or placebo, you will also receive probiotic capsule. We are aiming to recruit 132 participants into this trial.

Why is this study important?  Management of the symptoms of Covid-19 are currently supportive until anti-viral medicines and preventive vaccines are developed. Most patients with the disease recover fully, but about 20% require hospital treatments and 10% require intensive care. Effective treatments for Covid-19 infection are in development but will take some time. We do not know whether dietary factors increase the risk of catching the virus but it is known that people with pre-existing health conditions are more vulnerable to the complications of infection. One possible explanation for this is a pre-existing gut bacterial flora could adversely affect immunity.

What if I do not agree to take part? Participation in this study is entirely voluntary. Agreeing, or not agreeing, to enter this study does not change in any way the other treatments that you will receive connected to your disease.  If you do agree to participate, but later decide to withdraw from the trial at any stage, this would also not in any way influence future treatment decisions. We will also ask you if we can inform your GP that you have entered this study. A doctor or nurse may need to access your hospital medical notes, especially if you are admitted to hospital.

Giving consent to take part in this clinical trial. Attached to this Participant Information Sheet is a Consent Form. Because Covid-19 is highly infectious, if after you have read this leaflet and have had the opportunity to discuss it with your family and / or a member of the research team, you wish to participate, you will be able to give your consent to a member of the research team over the telephone, if we are unable to recruit you in person. We will ask you to sign and date the attached Consent Form at the same time, and return it in the pre-paid envelope.

However, we would ask that you do not post it until you have been advised that you can end your self-isolation, if applicable.

 What will you have to do if you enter the study? If you agree to take part in the study, you will be asked some questions about your current symptoms and well-being, as well as past medical history, medication, diet, smoking habits and exercise levels. You will receive healthy living advice and encouragement to exercise regular in the fresh air. You will be randomised to receive either the study food supplement orplacebo, and you will be asked to take one capsule, two times a at the same as your probiotic capsule, for four weeks or as long as your symptoms continue. You will be sent the capsules with clear instructions on how and when to take them.

A member of the research team will contact you once a week (at dates and times convenient for you) to ask you:

  • to give your highest daily temperature reading, if you have a raised temperature
  • to score your cough according to the Cough Symptom Score, if you have one
  • to score how you have been feeling using the Subjective Well-Being (SWB)
  • to score your levels of fatigue (tiredness) using the Chalder Fatigue Scale
  • if you have developed any other symptoms
  • if you have had any visits to the hospital

What is randomisation? This means that it is down to chance whether you receive the food supplement or placebo. After consent, a member of the research team will open an envelope (numbered consecutively), and within each envelope is a card stating ‘capsule A’ or ‘capsule B’, and this is the capsule that you will receive, which will be sent to you in the post if we are unable to recruit you in person. Neither you nor the research team will know whether capsule A or capsule B is the supplement or placebo, as both the capsules and the packaging, will look the same. You will have a 50% chance of receiving the food supplement, and a 50% chance of receiving the placebo (called 1:1 randomisation). All participants will receive the probiotic capsules.

About the capsules? The cylindrical capsule measures 21.4mm long, and is best taken with a drink. It can be taken with or without food. If you find it difficult to swallow the capsule whole, it can be opened up and added to food. The supplement and placebo have been produced by a fully-licensed UK manufacturer who has fulfilled all necessary EU and UK regulations for nutritional and food products. The capsule, given randomly to half of the participants, will contain the dried food extracts of a citrus fruit, turmeric, Aloe vera, pomegranate and chamomile. The other half of participants will receive a capsule which looks the same as the food supplement, but is actually a simple bulking agents thought to have no significant activity. This is known as a placebo. Neither you nor the research team will know which you have been randomised to. All participants will receive probiotic capsules containing a bacteria commonly found in food called lactobacillus.

How long will the trial last?  If you agree to take part in the study, you will be asked to take the capsules for 4 weeks or until you recover from your symptoms, from the date that you receive them. You will be contacted by a member of the research team weekly, for 4 weeks or until you have fully recovered from your Covid-19 symptoms. You can, of course, withdraw from the study whenever you wish.

Will you have to change your diet? No, you will not have to change your diet and you are completely free to choose whatever you wish to eat and drink, as are the people who live with you.

Possible side effects. Based on information from previous trials of these ingredients, the chance of side effects is small. About 8% of participants experienced some mild flatulence (wind) or loose stools. Any possible side effects will be recorded in trial forms during your telephone consultations, but if in the meantime you get a symptom which began after you started taking the capsules, you are asked to contact the research team on 01234 795 787.

Possible interaction with other drugs. No person in a trial involving a similar supplement experienced any adverse effect on their blood pressure (if on anti-blood pressure medication), or INR (if on warfarin). People on warfarin are not excluded from this intervention.

Will the information collected during the study be confidential?  All the information you provide will be known only to the research team. Any trial results which are published in medical journals or at conference, will not identify you or any other individuals. We will make sure that no-one can work out who you are from the reports we write. If you consent to take part in this study, your records will be kept within the research unit at The Primrose Unit, Bedford Hospital, for 10 years. All data collected during the study will be processed and stored in accordance with the guidelines set out in the Data Protection Act 2018 and the Good Clinical Practice (CGP) guidelines. Your GP will be informed of your participation in the study, unless you request otherwise on the Consent Form.

What are your choices about how your information is used? You can stop your participation in the study at any time, without giving a reason, but we will keep information about you that we already have. We need to manage your records in specific ways for the research to be reliable. This means that we won’t be able to let you see or change the data we hold about you. You can find out more about how we use your information:

  • at www.hra.nhs.uk/information-about-patients/
  • via our leaflet available from Bedford Hospital’s Information Governance Officer, Daniel Smith, on 01234 355122 ext. 5082, email daniel.smith@bedfordhospital.nhs.uk
  • by contacting the Research Manager, Madeleine Williams, either by telephone:  01234 795 787 or email:  madeleine.williams@bedfordhospital.nhs.uk.


Who is funding this study? This study is funded by the Primrose Unit Fund (folio account. 013096), which is part of ‘Bedford Hospital Charitable Funds’, registered charity number: 1061003. The research team involved in the study are not being paid to recruit you into the study. There are no copyright or patents issued on any of the investigational products and the anonymised results of the study will be published the public domain.

Regulation and design: This trial has been approved by the Bedford Hospital Research, Development and Innovation Department and the National Research Ethics Committee (Sheffield 20/YH/0164). It has been registered on the European trials database, EudraCT (number 2020-001532-10), and Integrated Research Application System (number 282517).  The study will be independently audited by an external agency to ensure accuracy and probity.

 What if you have any further queries about this trial?  Please contact Madeleine Williams, Professor Thomas’ Research Manager, on 01234 795 787 or email: madeleine.williams@bedfordhospital.nhs.uk.

Additional concerns. If you have any additional comments or concerns about this study, you may discuss these with the Investigator, Professor Robert Thomas. If you wish to go further and complain about any aspect of the way in which you have been approached or treated during the study, you should contact the Bedford Hospital Patient Advice and Liaison Service Lead, Jessica Toraman, on 01234 355122 ext. 4624. In the event that something does go wrong and you are harmed during the research and this is due to someone’s negligence, you may have grounds for legal action for compensation against Bedford Hospital, but you may have to pay for legal costs. The National Health Service complaints mechanisms will still be available to you.

The research team thank you for taking time to read this information sheet and for considering participating in this new research study.


Professor Robert Thomas MRCP MD FRCR
Consultant Oncologist Bedford and Addenbrooke’s Hospital.
Visiting Professor, University of Bedfordshire