An interventional study of Carrageenan baked in bread and Xanthan and guar-gum baked in bread in Healthy Adult, sponsored by Siv K Bohn. Not yet recruiting at 1 site in Norway. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Siv K Bohn · Not applicable, Interventional, and Treatment
Food additives, in particular hydrocolloids (thickening, gelling and stabilising agents), are widely used in the food supply. Concerns about carrageenan have led the food industry to replace it with alternative hydrocolloids, yet no one has compared these different commercial additives with respect to their effects on health. Experimental studies indicate that hydrocolloids can interact with the intestinal barrier, gut microbiota and immune signalling, with possible implications for both the gut-liver and gut-brain axes, but how they compare in humans is unknown.
This study investigates how different food additives affect health in healthy adults. In an initial run-in period, all participants follow a standardised diet low in food additives to establish a common background diet. Participants are then randomised to receive foods containing different hydrocolloids - carrageenan and its commercial replacements - or a reference dietary fibre as comparator, on top of the shared background diet.
The study examines effects on the liver, gut microbiota and short-chain fatty acid production, as well as measures relevant to the gut-brain axis such as mood, gastrointestinal symptoms and sleep. By providing the first controlled human comparison of carrageenan and its replacements, the study addresses a timely public health and regulatory question: whether the reformulation already adopted by the food industry has any measurable consequences for gut, liver and brain health.
This is the only study on the registry with Siv K Bohn as lead sponsor.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
3 weeks
Other: Carrageenan baked in bread
3 weeks
Other: Xanthan and guar-gum baked in bread
3 weeks
Other: Gellan baked in bread
3 weeks
Other: Potatoe fiber baked in bread
Carrageenan baked in bread
Also known as: Kappa-carrageenan baked in bread
Xanthan and guar-gum baked in bread
Also known as: Xanthan, guar-gum
Gellan baked in bread
Also known as: gellan
Potatoe fiber baked in bread
Also known as: Potatoe fiber
Serum aspartate aminotransferase (AST)
Serum AST concentration (U/L) measured by standard clinical biochemistry.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Change in serum alanine aminotransferase (ALT)
Serum ALT (U/L) by standard clinical biochemistry, as a liver-specific secondary marker supporting the primary outcome (AST).
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Serum gamma-glutamyl transferase (GGT)
Serum GGT (U/L) by standard clinical biochemistry, as an additional liver marker.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Gut microbiota composition and function
Outcomes include alpha diversity, beta diversity, taxa abundance and functional pathways.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Faecal short-chain fatty acid (SCFA) concentrations
Concentrations of Short chain fatty acids in faeces, measured by gas chromatography.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Faecal inflammatory biomarkers (e.g. calprotectin)
Biomarkers of intestinal inflammation in fecal extracts.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Systemic inflammatory markers
Circulating markers of systemic inflammation, including high-sensitivity CRP and panels of cytokines.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Metabolic markers
Metabolic markers (e.g. fasting glucose, fasting insulin (with HOMA-IR), and fasting lipid profile).
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Appetite-regulating hormones
Fasting concentrations of appetite-regulating hormones (e.g. GLP-1, PYY, ghrelin), measured in blood.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Exploratory biomarkers of gut-liver and gut-brain signalling
Exploratory biomarkers of inflammation, intestinal integrity, metabolism, and gut-liver and gut-brain signalling, analysed in blood and faecal samples. These may be extended as additional analyses are performed on stored samples.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Stool consistency (Bristol Stool Scale)
Self-reported stool form assessed by the Bristol Stool Scale. Reported in connection with the fecal sampling.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7
Gastrointestinal symptoms (GSRS-IBS)
Self-reported gastrointestinal symptoms assessed by the Gastrointestinal Symptom Rating Scale for IBS (GSRS-IBS).
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Depression (PHQ9)
Self-reported symptoms assessed by PHQ-9 (depression)
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Anxiety (GAD-7)
Self-reported symptoms assessed by GAD-7 (anxiety)
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Obsessive-compulsive symptoms (OCI-R)
Self-reported symptoms assessed by OCI-R (obsessive-compulsive symptoms),
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Sleep (Bergen Insomnia Scale - BIS)
Self-reported symptoms assessed by (Bergen Insomnia Scale - BIS)
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Health-related quality of life (SF-36)
Health-related quality of life assessed by the SF-36 health survey.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Physical activity
Self-reported physical activity assessed by selected validated items.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Personality traits
Personality assessed by the BFI-20 (Norwegian short form of the Big Five Inventory)
Time frame: Baseline
Dietary intake
Dietary intake assessed by 3-day dietary records (two weekdays and one weekend day) using household measures, including energy and macronutrient intake, micronutrient intake, dietary fibre, and intake of food groups.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Additive intake
Intake of food additives, including hydrocolloids, estimated from 3-day dietary records linked to a food additive composition database.
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
BMI
Self-reported body weight
Time frame: Baseline, end of run-in (week 3), end of intervention (week 6/7)
Attitudes to additives in food
Self-reported on a 5 item Likerts scale
Time frame: Baseline
Compliance to the intervention
Weekly reports on the intake of intervention food (2 slices of bread, 1 slice or none)
Time frame: Week 4, 5, 6 (and 7)
Health problems
Self reported new health problems
Time frame: Week 1-7
Use of antibiotics
Self-reported history of antibiotic use in defined life periods (early childhood, adolescence, and ages 16-20), examined for exploratory associations with baseline gut microbiota composition. Analysed as hypothesis-generating.
Time frame: Baseline
Use of alcohol
How often do you drink alcohol?
Time frame: Baseline
Plan to share: Undecided
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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