Condition category
Digestive System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
The human gut plays host to tens of trillions of different bacteria, which are known as the “gut flora”. The bacteria present in the gut flora are often referred to as “good” or “friendly” bacteria, because they assist in digestion and help to produce important vitamins for the body. One of the most common groups of bacteria that live in the gut is bifidobacteria, also known as lactic acid bacteria. Having the right levels and a good variety of gut bacteria is important for healthy development in children and good general health. It is thought that the colonization of the gut with different types of bacteria begins early in life, and can be affected by their inherited characteristics (genetic profile), how they are born (natural delivery or caesarian section) and whether they are breast fed. An initial study looked at the development of bacterial colonization in the gut by assesseing faecal samples (excrement), and the components of breast milk to see if it plays a role. This follow up study is conducted when the child is aged between 4 and 7 years old aims to look at the colonization of the gut (particularly the bifidobacteria) in childhood, and whether it has an effect on the child’s health.

Who can participate?
Children aged between 4 and 7 who took part in the initial study as a baby.

What does the study involve?
The parent/guardian of the child completes a number of questionnaires about their child’s health and disease history and the child is observed by a researcher in order to assess their personality. The child also provides two faeces samples 7-9 days apart so that the levels of bacteria present in their gut, particularly bifidobacteria, can be measured.

What are the possible benefits and risks of participating?
There are no anticipated benefits or risks for participants involves in this study.

Where is the study run from?
Research Unit Stuivenberg (Belgium)

When is the study starting and how long is it expected to run for?
November 2015 to September 2016

Who is funding the study?
Yakult Honsha European Research (Belgium)

Who is the main contact?
1. Dr Steven Ramael (scientific)
2. Dr Junji Fujimoto (scientific)

Trial website

Contact information



Primary contact

Dr Steven Ramael


Contact details

ZNA Stuivenberg
Lange Beeldekensstraat 267



Additional contact

Dr Junji Fujimoto


Contact details

Yakult Honsha European Research Center for Microbiology
Technologiepark 4
+32 9 241 11 34

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The Follow-up Study of YAK.1.C.A: Investigation on the impact of continuous colonization of Bifidobacteria during early life on child’s health


Study hypothesis

The aim of this study is to investigate if the presence of bifidobacteria during early life, analyzed
in Study Yak.1.C.A., and its persistence impact on child’s health and personality.

Ethics approval

Commissie voor Medische Ethiek-Ziekenhuis Nerwek Antwerpen, 07/04/2016

Study design

Single-centre observational trial

Primary study design


Secondary study design

Cohort study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet.


Intestinal microbiota


Legally acceptable representative will fill out questionnaires regarding the subject’s disease
history and demographic as well as the Children’s Behaviour Questionnaire in order to examine
their personality. Two faecal samples for each subject will be collected with an interval of 7 to 9
days for microbiological analysis.

Intervention type


Drug names

Primary outcome measure

The study consists of “Screening day (S)”, “First faecal delivery day (F1: within 28 days after
Screening day)” and “Second faecal delivery day (F2: within 7 to 9 days after F1)”. Subjects will
not be allowed to drink fermented milk between F1 and F2
1. Subject’s disease history will be collected by questionnaire on F1, and additionally on F2 in
order to follow the disease occurrence in the interval
2. Subject’s demographics will be collected by questionnaire on S, and additionally on F1 and F2
in order to follow the status of fermented milk and intestinal drugs (e.g. antibiotics) ingestion in
the intervals
3. Children’s personality will be assessed based on Children’s Behavior Questionnaire collected
on F1
4. Faecal microbial composition, diversity and the absolute number of specific bacteria will be
analyzed by 16S rRNA metagenomics or quantitative polymerase chain reaction (PCR) targeting
bacterial DNA extracted from the faeces collected on F1 and F2. Preserved bacterial DNA from
Study YAK.1.C.A. will also be analyzed.
5. Persistence of bifidobacteria from early life will be evaluated by comparing the homogeneity
of bifidobacterial strains isolated from faeces collected on F2 to those isolated in Study YAK.1.
C.A. by using multilocus sequence typing (MLST)

Secondary outcome measures

No secondary outcome measures

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Male or female subjects aged between 4 and 7, who participated as a neonate in Study Yak.1.C.A.

Participant type

Healthy volunteer

Age group




Target number of participants

111 participants (maximum)

Participant exclusion criteria

1. Participation in another clinical study during the study or within 30 days prior to entry in this study
2. A condition that, in the opinion of the Investigator, could compromise the well-being of the subject or course of the study, or prevent the subject from meeting or performing any study requirements

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

SGS LSS. Clinical pharmacology Unit Antwerpen
Lange Beeldekensstraat 267

Sponsor information


Yakult Honsha European Research Center

Sponsor details

Technologiepark 4

Sponsor type




Funder type


Funder name

Yakult Honsha Co., Ltd.

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication in a peer reviewed journal.

Intention to publish date


Participant level data

Stored in repository

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

13/04/2016: Ethics approval information added. This study is a follow up of the YAK.1.C.A study, available at