Probiotic Research

I am currently looking for participants who train at least 3 times per week and would be interested in taking part in research looking at the effect of probiotics on stress and recovery in sports.

Please find more details in the participant information sheet below and attached.

Participant Information Sheet

The Research Project    

Title of the project: Effect of probiotic supplementation on stress and recovery during competition season

  • The purpose of this study is to investigate whether taking a probiotic will reduce stress and improve recovery of athletes during competition season.
  • You are invited to take part in this study which aims at improving knowledge about the effects of probiotics for athletes.
  • Organiser of the study: Evelyn Dorkel, registered dietitian and student of a degree in Sports Nutrition at St Mary’s University
  • The information collected will be kept confidential in an encrypted file accessible only by the organiser and supervisor of the study. Any published data will be anonymised in accordance with the Data Protection Act 1998.
  • For further information, please contact Evelyn Dorkel at

Your Participation in the Research Project

  • You have been invited to take part in this study because you are a member of an athletic team currently training at least 3 times a week. You are in general good health, do not suffer from any mental or inflammatory health issues and are not taking any antibiotics or cortisone.
  • Taking part in the study is voluntary and it is up to you to decide whether to take part. If you decide to take part you will be given this information sheet to keep and be asked to sign and return the consent form enclosed. If you decide to take part you are still free to withdraw at any time and without giving a reason.
  • Once you have agreed to take part in the study, the organiser will contact you and discuss the study in detail.
    • After agreeing to take part in this study, you will be asked to stop eating any probiotic foods, drinks and supplements for 2 weeks (wash-out period) plus the duration of the study (8 weeks). You will also be advised to maintain your habitual diet for the whole duration of the study.
    • During the last 3 days of the wash-out period, you will be advised to log your food and fluid intake for 3 days. On the day before commencing taking the probiotic supplement, you will be asked to fill in a stress and recovery questionnaire (which takes about 5-10 min). The organiser of the study will provide you with 56 probiotic capsules or placebo.
    • You will be asked to take one probiotic/placebo capsule per day during 8 weeks whilst maintaining your typical training schedule for 7 weeks but increasing your training load by 50% during the last week of the intervention period (e.g. if you typically train 3 times per week, you will be asked to train 5 times during the last week of intervention).
    • You will be asked to log any cold and flu symptoms, diarrhoea, constipation and abdominal pain episodes during the intervention and fill in another food and fluid diary during the last 3 days of this intervention period. At the last day of your intervention, you will be asked to fill in the same stress and recovery questionnaire again.
  • In order to take part in this study, you will need to attend 2 meetings of approx. 15 min. For this, the organiser will come to your training location. During the study you will need to take one capsule of the probiotic or placebo daily and provide two 3 day food diary.
  • The risks to participation in the project have been identified as being low. Probiotic intake is safe in healthy people but can in rare cases lead to a slight change in digestion (bowel consistency, bowel frequency and bloating) which is often transient and benign. The probiotic supplement has been approved by informed Sport and should be free from contamination. You should not take part in this study if your general practitioner (GP) has advised you not to take probiotics. For any health concerns, contact your GP.
  • Agreement to participate in this research will not compromise your legal rights if something goes wrong.
  • Your data will only be assessed by the organiser and her supervisor. Any published data will be anonymised in accordance with the Data Protection Act 1998.