Gut Microbiome and Blood Markers After Habitual Herbal Tea Consumption

TeTrimTeas intends is to establish a long-term cooperative with local growers and producers who will become partners in the business, with profit share to local growers and producers. The overall aim of the company is to produce quality, science-based botanical/herbal teas to improve health and wellbeing, growing as many of the ingredients locally and organically, to reduce food-to-fork miles within the decarbonisation and sustainability agendas in Wales.

TeTrimTeas have created herbal green tea blends, improving on existing Chinese formulation, and would like to test it as 'health tea'. The recruited cohort will be randomised into one of three intervention teas (green tea control, senna herbal mix and rhubarb root herbal mix). They would like to explore if consumption of the teas for 21 days has an impact on digestion and potentially help control weight gain.

Aberystwyth University will use high resolution metabolomics to investigate the chemical composition of capillary blood samples, in particular the short chain fatty acids. They will also assess lipid composition in capillary bloods and the microbiome of stools. Diet data, stool consistency and anthropometric measurements will be collected pre and post intervention. Results will advance product development and data would be used in grant applications into the health benefits of the herbal teas.

TeTrimTeas has created herbal green tea blends, improving on existing Chinese formulation, and would like to test it as 'health tea'. The recruited cohort will be randomised into one of three intervention teas (green tea control, senna herbal mix and rhubarb root herbal mix). This will be double blinded so neither the participant nor the researcher will know what group they have been allocated into. Information can be disclosed at the end of the study. Participants will come to WARU or Trimsaran Community Health Centre for induction and study visits.

The experimental sequence

'Diet-monitoring' period (two days before the study)

Prior to the experimental session it is important that all participants undergo a period where foods are recorded. This will help the researchers interpret any results after consumption of the test/control food. The researchers would ask them to refrain from taking any over-the-counter medication (such as ibuprofen, paracetamol, aspirin, cough/ cold remedies) or herbal supplements, and to let us know if they find that it is necessary to take any such medication during the trial.

Experimental session- 21 days

Morning: Participants will come to WARU or Trimsaran Community Health Centre for their pre-organised timeslot to allow researchers to collect a fasted capillary (fingerpick) blood samples and stool sample. They may consume their breakfast after their visit. They will also collect their tea bags. Researchers will also take participants weight and height and collect diet data (PDQS) and stool scores (Bristol Stool scale).

Over 21 days: the researchers would ask the participants to consume a cup of tea after their last meal/snack of the day (post 6pm) daily, for 21 days. The researchers would ask them not to consume anything after the tea. In a cup/mug the researchers would ask them to place a 2.5g tea bag and add 190ml of hot water (80-100◦C) and stir clockwise 10 consecutive times to allow for optimal infusion and then allow to brew for 5 minutes, before removal.

After the experimental period:

Before their final visit (or at their final visit): the researchers would like participants to fill in another food questionnaire and a stool scale.

Morning of their final visit. The researchers would ask the participant to come to WARU or Trimsaran Community Health Centre for their pre-organised timeslot to allow us to collect a fasted capillary (fingerpick) blood samples and stool sample. The researchers will also take their weight and height. They may consume their breakfast after their visit. Afterwards, they can go back to their 'normal' eating pattern.

Eligibility Criteria:
Inclusion Criteria:

* Consenting adults \>18 y Age
* Commit to fasting capillary blood collection
* Commit to stool sampling collection
* Able to refrain from taking any over-the-counter medication or herbal supplements during the diet monitoring and experimental periods.
* Able to prepare and consume the tea during the experimental days, after the last meal/snack of the day and not to consume anything afterwards
* Fill in diet diaries, FFQ and stool ranking
* Able to inform the researcher if any antibiotics or heavy alcohol is consumed over the intervention period

Exclusion Criteria

* Showing (or anyone within the household) any COVID-19 symptoms (see COVID-19 basic health screen)\*
* Higher risk or vulnerable from coronavirus or live with someone at a higher risk of a severe illness from COVID-19 (over 70, undergoing cancer treatment, high risk of getting infections).
* Had a letter from the NHS advising you to shield (isolate)
* Had been at risk of exposure to COVID-19 such as travel, contact with someone with COVID-19, been exposed to the virus, or has been asked to self-isolate by the track and trace system.
* Serious health conditions that require daily long-term medications (including immunosuppressants)
* A history or current diabetes, lung issues, gut inflammation (Crohns, IBD), digestive disorders
* Diagnosed with a serious health condition within the last 12 months
* Pregnant
* Play sports at a high level (more than 7h/week or 1h/day)
* Smoking
* consume high dose of alcohol \> 21 unit per week for men and \> 14 units per week for women
* Food allergy /food intolerance/ eating disorder or are on a specially prescribed diet

  * If the potential participant has had COVID-19 previously (and are fully recovered and not within isolation) then they are eligible to join the study