Plain English Summary
Background and study aims
Functional gastrointestinal disorders such as Irritable bowel syndrome (IBS), functional dyspepsia/bloating and functional diarrhea are common, long-term conditions that affect the digestive system. The symptoms can vary greatly from person to person but typical symptoms include abdominal pain, bloating, diarrhea, gas and stomach rumble. The exact cause of functional symptoms are not known. However, many think that symptoms are related to hypersensitive gut and stomach, and that foods play major role in triggering symptoms. There is no cure for functional gastrointestinal disorders but dietary changes can help to ease the symptoms. The role of lactose in inducing gut and stomach symptoms in lactose intolerant people is widely known. However, the role of milk proteins, casein and whey, is poorly understood. Some people with sensitive gut and stomach report that milk and other dairy products commonly trigger symptoms; it is possible that proteins trigger these symptoms. Early studies have suggested that hydrolyzed milk protein might be better tolerated than intact milk protein. The aim of this study is to compare the effects of regular milk protein to hydrolyzed milk protein in people with sensitive stomach and gut, i.e. in functional gastrointestinal disorders.
Who can participate?
People aged 18-65 who have at least one of the following functional gastrointestinal disorders: irritable bowel syndrome, functional dyspepsia/bloating or functional diarrhea
What does the study involve?
The study involves two separate 10-day test periods which are spaced at least 10 days apart. One involves eating partially hydrolyzed milk products and the other involves eating regular milk products; both products are chocolate milkshakes and they are provided for free. The diet is meant to be otherwise as normal as possible. The participants take part in both test periods but they are taken in a random order. At the beginning and end of each test period participants give a blood and urine sample and answer questions related to stomach and gut symptoms. Over the following 10 days, participants are asked about symptoms they are having. At the end of the study, the participants are entitled to approximately 30 min dietitian consultation given by the designated study dietitian. Participants can withdraw from the study at any time point.
What are the possible benefits and risks of participating?
There are no direct benefits of taking part, although participants are able to receive information about the state of their health. Risks of participating include the possibility that milk protein products induce stomach and gut symptoms.
Where is the study run from?
Valio Oyj Ltd
When is the study starting and how long is it expected to run for?
August 2019 to December 2019
Who is funding the study?
Valio Oyj Ltd
Who is the main contact?
Dr Reijo Laatikainen
Effects of milk protein hydrolysis on gastrointestinal symptoms in functional gastrointestinal disorders: a randomized controlled trial
Partially hydrolysed dairy protein is better tolerated in functional gastrointestinal disorders than intact dairy protein.
Approved 22/05/2019, ethics committee of the Hospital District of Helsinki and Uusimaa (HUS keskuskirjaamo, Tynnyrintekijänkatu 1C, 00290 Helsinki, Finland; Tel: +358 (0)9 4711 (ask to connect to ethics committee); Email: firstname.lastname@example.org), ref: HUS/576/2019
Single-centre double-blind cross-over randomized controlled trial
Primary study design
Secondary study design
Randomised cross over trial
Patient information sheet
Patient information is in Finnish and available upon request
Functional gastrointestinal disorders including irritable bowel syndrome, functional dyspepsia/bloating and functional diarrhea
Participants receive the 10-day intervention and 10-day control treatment in a random order, which are delivered at separate study visits (wash out at least 10 days apart). At baseline, participants give a blood sample, an overnight urine sample and respond to IBS-SSS questionnaire.
Intervention: Participants will be given hydrolysed milk protein products (milkshakes) for daily consumption, equivalent to approximately 50 grams protein per day. Otherwise, the participants continue on their habitual diet.
Control: Participants will be given regular milk protein products (milkshake) for daily consumption, equivalent to approximately 50 grams protein per day. Otherwise, the participants continue on their habitual diet.
In each condition, at the beginning and at the end of each treatment period, i.e. control and intervention period, blood and urine samples are collected and symptoms are monitored on daily basis.
Primary outcome measure
1. Gastrointestinal symptoms measured by IBS-SSS scoring system (Francis et al. 1997) at baseline and at the end of each treatment period
2. Abdominal pain, borgorygmia, intestinal gas and bloating evaluated on 4-point Likert scale daily
Secondary outcome measures
1. Markers of immune activation/low-grade inflammation: e.g.IL-6, IL-1B and TNF-alfa from plasma using high-sensitivity ELISA kits and methylhistamine from overnight/12 h urine samples also using ELISA
2. Markers of intestinal permeability: FABP-2 from plasma using ELISA
All biomarkers are measured at the beginning and the end of each 10-day treatment period
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Aged between 18 and 65 years
2. Irritable bowel syndrome, functional dyspepsia/bloating and functional diarrhea (all defined by Rome IV criteria)
Target number of participants
Total final enrolment
Participant exclusion criteria
1. Organic gastrointestinal disease such as Crohn's disease, ulcerative colitis, colorectal or gastric or any cancer
2. Pregnancy or breastfeeding
3. Significant abdominal surgery (e.g. bowel resection)
4. Difficult to treat constipation
5. Medication that affects intestinal motility and/or pain perception
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Booston Oy Ltd
Valio Oyj Ltd
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Publication in a peer-reviewed journal. Upon request the protocol can be sent depending on the scientific soundness of the request.
IPD sharing statement
For commercial reasons the developer of the milk protein products is not ready to make the data freely available. The data will be kept at the premises of development and research department in Valio Oyj Ltd.
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
2020 results in https://pubmed.ncbi.nlm.nih.gov/32708428/ (added 02/12/2020)