RIGHTWHEY - Responders In Gut HealTh Markers Using Fermented WHEY (RIGHTWHEY)

Investigating the Effect of Fermented Whey Concentrate on Gut Microbial Activity: Does Butyrate Matter?

This 8-week intervention will investigate the effect of daily consumption of a fermented whey concentrate on the short-chain fatty acid profile of faeces in healthy individuals. This study will help us understand if consumption of fermented foods rich in lactic acid have a beneficial effect on gut health.

The 8-week dietary supplementation trial will investigate the action of exogenous lactic acid consumption on the activity (using short-chain fatty acid) and composition of the gut microbiota. Participants will be stratified according to their baseline faecal butyrate levels. Therefore volunteers will be asked to provide two faecal samples one week apart. Based on the average absolute level of butyrate in the faecal samples, volunteers will be stratified into either low, moderate or high baseline butyrate levels (detailed in table 1 below). The levels for faecal butyrate for each group are set based on a meta-analysis of 9 human studies of healthy volunteers carried out at the Rowett Institute (n=116; LaBouyer et al, 2016, unpublished). Thresholds were derived from the boundaries of tertiles. Therefore, the moderate butyrate producers represent the middle 33% (see table). Each stratification arm will have a minimum of 17 study volunteers bringing the total to n=51. This has been set to ensure the completion of at least 45 volunteers. To optimise equal gender distribution amongst all study arms a minimum of 5 females and 5 males will be recruited for each arm. Stratification Butyrate range Low ≤13 mM Moderate butyrate 13 - 20mM High butyrate ≥20mM Primary and secondary outcomes will be analysed between the low and high butyrate producing groups as well as the overall group effect on everyone.

The intervention will be provided in non-descript bottles. Fermented whey is mixed with sugar-free flavoured water to mask its taste from participants.

Volunteers will receive the premixed water and fermented whey in weekly deliveries in 1.5L bottles and a drinking glass with a clear indication of the required 200ml volume. Participants will be asked to drink 200 ml of the supplemented water twice daily for the active intervention period.

The investigated dietary supplement is a form of lacto-fermented whey concentrate (FWC), which has been deproteinised and then diluted (1/20) in sugar-free flavoured water to improve palatability. The main solute within the lacto-fermented whey is L-(+)-lactic acid (7%), produced through bacterial fermentation of the milk sugar lactose. The research team will provide non-descriptive bottles of drink to all volunteers. The flavour of the FWC will be masked by the flavoured water. In order to assess compliance and minimize an initial treatment effect, a 14 day run-in period during which only flavoured water is to be consumed will be completed by all volunteers. At the same time, this period will act as a wash-out, as volunteers will be asked to abstain from the use of any dietary supplements during this period and the rest of the study. The daily energy content of the FWC is 4kcal.

Change in relative proportion of butyrate (percentage of total SCFA - sum of propionate, butyrate, acetate, valerate, iso-valerate, iso-butyrate, succinate, lactate mM (millimolar values from gas chromatography) and absolute concentration (mM millimolar) when comparing volunteers as stratified by faecal butyrate levels at start of study. A comparison will be made between the butyrate concentration-dependent groupings.

Baseline measurement (Visit 1) and end of study (visit 3, 8 weeks later) [Baseline butyrate calculated from the average of two values per individual at Day -7 and Day 0; End of study value is the average from two samples collected at Day 49 and 56

Change in relative proportion of butyrate (percentage of total SCFA) and absolute concentration (mM, millimolar) across the total study group

Baseline measurement (Visit 1) and end of study (visit 3, 8 weeks later) [Baseline butyrate calculated from the average of two values per individual at Day -7 and Day 0; End of study value is the average from two samples collected at Day 49 and 56

Changes in the composition of the microbiota will be based on next-generation sequence analysis of 16S rRNA (ribosomal ribonucleic acid) genes extracted from faecal samples provided by all volunteers

Changes in frequency or consistency of bowel movements and gastrointestinal well being will be assessed with a self-administered weekly questionnaire (ranked on a linear likert scale). The questionnaire asks volunteers to rank nausea, bloating, flatulence, abdominal cramps, rumbling, indigestion, fullness/distension and early satiation over the last 24 hours. The scale is scored from -3 being considerably less, -2 moderately less, -1 for slightly less and 0 for as usual. Responses such as slightly more are scored as 1, moderately more as 2 and considerately more as 3. Scores will be aggregated across all categories and compared as a whole to represent general GI wellness changing throughout the intervention. Participants have a blank box to fill in with the number of bowel movements in the last 24hr and are asked to rank them on the Bristol stool scale (0-7, visual guide included in the questionnaire). Scores will be assessed as averages over the control and intervention periods.

Comparison of change in response to Oral glucose tolerance test (3 hours) using the total and incremental area under the curve (AUC)for both glucose and insulin concentrations. Both values are measured in arbitrary units and calculated by the standard trapezoid method. Incremental AUC is the baseline corrected output for total AUC. Comparison will be made between group averages at baseline and post-intervention

Change in score in health-related quality of life questionnaire General health is ranked on a scale of excellent, very good, good, fair and poor with scores ranging from 1 - 5 respectively. Volunteers are asked to write the relevant days they have been affected by: physical health, mental health or impaired by poor mental and physical health, or pain over the last 30 days. Participants are asked to respond to the following questions relating to the past 30 days: how many days have they felt sad/blue, worried/tense/anxious, did not have enough rest/sleep and have felt very healthy and full of energy. Each category will be individually compared at baseline and post-intervention.

Change in Breath test assessment of hydrogen and methane levels (given in ppm - parts per million) and faecal pH (using standard pH meter)

Inclusion Criteria: i. Men and women aged 18-68 years; BMI ranging from 18-35 kg/m2; measured at the screening visit Exclusion Criteria: i. smokers ii. subjects with: diagnosis of diabetes, pregnant, hypertension, renal, hepatic, haematological disease, coronary heart disease or any gastrointestinal disorder ii. unsuitable veins for blood sampling; iii. inability to speak, read and understand English. iv. Use of antibiotics within the last 3 months will automatically exclude volunteers. v. Vegans. Fermented whey concentrate, (FWC), is derived from milk (animal product) which excludes potential participants adhering to a vegan diet. vi. allergy to any of the following: cow milk, lactose, casein, whey, sucralose, acesulfame K, citric acid, potassium benzoate, fruit flavourings.