GOS to Reduce Symptom Severity in IBS

Inclusion Criteria: 1. Patients who have been diagnosed with IBS by a medically trained person/Health Care Professional (HCP). 2. IBS diagnosis to be confirmed according to the Rome-IV criteria by a primary or secondary care clinician, including a gastroenterologist, at study entry 3. An IBS Symptom Severity Scale score of ≥125 points at baseline 4. Male or female between 18 and 64 years of age (age ranges included) 5. Possession of a smartphone 6. Willing and eligible to provide consent and comply with protocol and product intake. Exclusion Criteria: 1. Unclassifiable IBS (IBS-U) as determined by Investigator 2. Use of products marketed as prebiotics, probiotics or synbiotics within 4 weeks prior to study entry (e.g. Yakult, Actimel, Activia, VSL#3, Kefir). o Regular cheese or yogurt containing lactic acid bacteria are not an exclusion criterion. 3. Systemic antibiotic or antimycotic treatment within 4 weeks prior to study entry 4. Use of laxatives or antidiarrheal medication within 1 week prior to study entry 5. An unstable antidepressant/antipsychotic treatment regimen within 3 months prior to study entry (i.e. treatment should be stable for at least 3 months prior to study entry). 6. Confirmed lactose intolerance, defined as patients who report response to dietary elimination of lactose/dairy products. Confirmation is patient-reported and not done within the scope of this study. 7. Confirmed food allergy, with reported confirmation based on OFC, IgE, or skin prick test. Confirmation is patient-reported and not done within the scope of this study. 8. Galactosemia (galactose metabolism disorder) 9. Following diets likely to affect study outcomes, including: o low FODMAP, KETO/high-fat, gluten free/coeliac, paleo, weight loss, caloric restriction, low-carb, 5:2/whole day energy restriction, Atkins/high-protein, sugar-free, single-food, juicing/any day of juicing, any other restriction diet (e.g. very low calory), or vegan diets (GOS is derived from cow's milk). 10. Severe illness(es) or medical condition(s), including gastrointestinal pathologies: o GI ulcers, coeliac disease, inflammatory bowel disease, bowel cancer, bowel resection, , bariatric surgery, acute or chronic diarrhoea secondary to confirmed infectious gastroenteritis, or enteral or parenteral nutrition. 11. Subjects suffering from auto-immune disorders (e.g. Rheumatoid Arthritis, Systemic lupus erythematosus, Multiple Sclerosis, Graves' Disease) that require treatment with an immune modulator treatment or anti-inflammatory medication 12. Surgical operations to the mouth or gastrointestinal tract within 4 weeks prior to study entry, or planned during the study o Appendectomy within 6 months prior to study entry 13. Recent unintended weight loss: o \>5% of total body weight within 6 months prior to study entry 14. Excessive alcohol consumption (\>14 units per week) and/or drug abuse 15. Pregnancy and lactation, or plan to become pregnant during the study period 16. Participation in other studies involving investigational or marketed products concomitantly or within 3 months prior to study entry 17. Changes in diet, supplement or medication use likely to affect study outcomes (i.e. medication that influences GI function) within 4 weeks prior to study entry or planned during the study (at the discretion of the Investigator). For example, the following medications will influence GI function and changes must be avoided: opioids, prokinetics (domperidone, metoclopramide, prucalopride), antispasmodics (peppermint oil, buscopan), and acid suppressants (PPI, H2 blockers). Of note: the intake of fibres (e.g. psyllium husk) may be used provided that the participant has been using this as a supplement for more than 4 weeks prior to study participation and intake does not change during the course of participation.