Strategies To OPpose Sugars With Non-nutritive Sweeteners Or Water (STOP Sugars NOW) Trial
Condition: Healthy; Overweight and Obesity; Metabolic Syndrome; PreDiabetes; Diabetes; Overweight; Obesity; Dysglycemia; Cardiovascular Diseases; Cardiovascular Risk Factor; Hypertension
MeSH terms: Cardiovascular Diseases; Obesity; Overweight; Metabolic Syndrome
Study type: Interventional

Summary: 
      Health authorities recommend a reduction in added sugars from sugar-sweetened beverages
      (SSBs) due to risk of obesity and diabetes. As a sugar-reduction strategy, finding the ideal
      SSB replacement is of the utmost importance. Those who are already consuming SSBs might not
      easily replace it with water and therefore non-nutritive sweetened beverages (NSBs) present a
      sweetened alternative, though guidelines recommend water instead of NSBs as a replacement for
      SSBs. Recent evidence suggests that saccharine, a non-nutritive sweetener, which is not found
      in NSBs, might induce glucose intolerance by altering gut microbiota in humans. It is
      currently not known if replacing SSBs with NSBs (which contain low-calorie sweeteners other
      than saccharine) or water will have any effect on the human gut microbiota and any downstream
      diabetic risk. The investigators plan to undertake a randomized controlled cross-over trial
      in 75 healthy adults to assess the effect of replacing SSBs with equal amounts of NSBs or
      water for 4 weeks on the composition and diversity of human gut microbiota, changes in
      glucose tolerance and total body fat in those who regularly drink SSBs. Each participant will
      act as their own control receiving each of the three interventions of SSB, NSB and water for
      four weeks in random order, each period separated by a four-week wash-out period. All study
      visits will occur at the Clinical Nutrition and Risk Factor Modification Centre at St.
      Michael's Hospital. This study will contribute to knowledge that will inform dietary
      guidelines and public policy with regards to the best possible replacement for SSBs. It will
      also shed light on the potential mechanism of the adverse effects of NSBs and if the
      replacement of SSBs by NSBs or water are in fact similar with respect to their effect on gut
      bacteria and any downstream diabetic risk.
    

Detailed description: 
      BACKGROUND AND SIGNIFICANCE:

      International health agencies and chronic disease associations have called for reductions in
      free/added sugars to ≤5-10% of energy to address the growing epidemics of obesity and
      diabetes. Attention has focused especially on the reduction of major source of free sugars,
      sugar sweetened beverages (SSBs), of which the excess consumption has been associated with
      weight gain, diabetes, and their downstream complications including hypertension and coronary
      heart disease (CHD). Ontario's Healthy Kids Panel, Health Canada, the Standing Senate
      Committee, the Heart and Stroke Foundation and Diabetes Canada have recommended policies to
      reduce SSBs including replacement strategies, taxation, and/or bans on advertising to
      children. A role for non-nutritive sweeteners (NNSs) in these policy options has been
      conspicuously absent.

      There is an emerging concern that NNSs may contribute to an increase in the diseases that
      they are trying to prevent. Systematic reviews and meta-analyses of prospective cohort
      studies have shown that NNSs are associated with increased risk of weight gain, diabetes, and
      CHD. Although this evidence is recognized to be at high risk of reverse causality and
      disagrees with the higher quality evidence from randomized controlled trials, several
      biological mechanisms have been proposed, among them changes in gut microbiome. One
      highly-influential study concluded that NNSs induce glucose intolerance through a loss of
      diversity in microbiome. This study, however, disagreed with a subsequent study and had
      several methodological weaknesses including the lack of a control group. Despite the
      uncertainties, these data have contributed to a negative view of NNSs in the media.

      There is an urgent need to address the ongoing concerns related to NNSs. Health Canada, in
      particular, has indicated that studies of sugar reduction strategies that use NNSs and target
      microbiome are an important research priority. The investigators propose to conduct a
      CIHR-funded randomized controlled trial that assesses the effect of a 'real world' strategy
      to reduce SSBs using non-nutritive sweetened beverages (NSBs) or water on gut microbiome,
      glucose tolerance, and cardiometabolic risk factors in overweight or obese participants.

      OBJECTIVES

        1. To assess the effect of replacing SSBs with NSBs or water on the first primary outcome
           of diversity of gut microbiome over 4-weeks in overweight or obese participants.

        2. To assess the effect of replacing SSBs with NSBs or water on the second primary outcome
           of glucose tolerance over 4-weeks in overweight or obese participants.

        3. To assess the effect of replacing SSBs with NSBs or water on the secondary and
           exploratory outcomes of body weight, blood pressure, glucose and insulin regulation,
           blood lipids, ectopic fat, liver fat, body adiposity, and diet quality over 4-weeks in
           overweight or obese participants

      PARTICIPANTS:

      Participants will be recruited from a population of healthy, adult men and non-pregnant women
      who are overweight or obese (BMI > 23 kg/m2 for Asian individuals and > 25 kg/m2 other
      individuals) who currently report drinking SSBs regularly (≥ 1 serving daily). 75
      participants will be recruited for the study. Of the 75 participants, 30 of them will be
      asked to consent to have an MRI taken to measure their liver and muscle adiposity.

      DESIGN:

      The trial is a four-week single-centre, open-label, randomized controlled cross-over trial
      with three arms (SSB, NSB, water) comparing the effect of replacing SSBs with NSBs or water
      on the gut microbiome. Each participant will act as their own control receiving the
      interventions for four weeks in random order, with intervention phases separated by four-week
      wash-out phases.

      POWER CALCULATION:

      The study will be performed in a total of 75 participants. It is powered to show a difference
      between the water, NSB, and SSB arms in 60 participants in the two primary outcomes. Assuming
      a drop-out rate of 20 percent, we would need 75 participants in order to have to power to
      detect a difference.

      The first primary outcome is in beta diversity of the gut microbiome communities of the
      participants between water and NSB groups via 16S ribosomal rRNA gene sequencing. The
      investigators used the micropower R package to compute sample size based upon the power of
      16S tag sequencing that can be analyzed using pairwise weighted UniFrac distances. UniFrac is
      a distance metric based upon the unique fraction of branch length in a phylogenetic tree
      built from two sets of taxa. Comparison of microbiome samples is performed via weighted
      UniFrac, which considers the relative abundance of taxa. The investigators simulated the
      within-group distance as 0.2, and the standard deviation (SD) of within-group distances as
      0.07. To detect a weighted UniFrac distance of 0.04, which is smaller than the effect
      observed in a studies of Suez et al. (0.05 derived from figure 5), and considering it is a
      cross-over study with a within-person correlation of 0.7, and taking into account multiple
      arms the investigators calculated that for above 95 percent power the investigators would
      need 60 participants in this study. Assuming a loss of 20 percent, the investigators will
      recruit 75 participants. The investigators are confident about detecting an alteration in gut
      microbiome diversity if it exists as previous studies show that small changes in diet causes
      significant alteration in gut microbiome taxa over a much shorter period (5 to 7 days) in
      fewer individuals (10 to 25 people).

      The second primary outcome is glucose tolerance, as measured by incremental Area Under the
      Curve (iAUC) from a 2-hour 75g OGTT. With 60 participants the investigators will have 89
      percent power (assuming absolute numbers for mean and SD from the investigators recent
      unpublished randomized trial) to detect a 20% change in mean iAUC between the water and NSB
      group if the direction of change is similar to Suez et al. while assuming a within-person
      correlation of 0.7 and taking into account the three comparisons. The 20% difference for
      glucose iAUC is based on the minimally important difference proposed by Health Canada to
      support postprandial blood glucose response reduction claims.

      This power calculation takes into account adjustment for multiple testing for both primary
      outcomes using the Benjamini-Hochberg procedure, which is a suggested method by the Food and
      Drug Administration in its "Multiple Endpoints in Clinical Trials Guidance for Industry"
      (https://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm536
      750.pdf). Benjamini-Hochberg procedure is a step-down method that controls for false
      discovery rate, while maintaining high power. The investigators will implement a truncated
      Benjamini-Hochberg method with parallel gatekeeping in which some portion of the unused alpha
      from each step is reserved for passing to the secondary outcome family if any of the primary
      outcome is significant. The alpha levels calculated for the primary outcomes is given in
      table 2. The study is also powered to show a difference between the three arms for secondary
      outcomes with an α=0.0125, the lowest possible starting α for secondary outcomes based upon
      the truncated Benjamini-Hochberg procedure.

      Sub-study: 1H-MRS will be performed in 30 subjects to assess intrahepatic and intramuscular
      fat. The investigators will have 99% power to show a difference in liver fat of 5% between
      the water and NSB arm for both hepatic and muscle fat assuming a between group SD of 4%, with
      a correlation of 0.65 and alpha of 0.05.

      RECRUITMENT:

      Using the Research Electronic Data Capture (REDCap) program, the Applied Health Research
      Centre (AHRC) will perform the randomization with no stratification. Following successful
      completion of the run-in phase and following measurements taken at the first study visit,
      participants will be randomized into groups, of a possible six, using a blocked (Latin
      squares) randomization. These groups will be sequences representing SSB, NSB and water
      groups. The Latin square sequences will be randomly allocated to participants with a similar
      number of participants allocated to each treatment sequence. The randomization schedule is
      also created by AHRC through REDCap. The participants will only be randomized and given their
      study drinks once all measures from the first study visit are collected.

      INTERVENTIONS:

      There will be three interventions: Participants will be provided with the SSB of their choice
      (355 ml, 140kcal, 39g sugars per can), equivalent NSB (355 ml, 0kcal, 0g sugars per can), or
      water (355 ml, 0kcal, 0g sugars per can or bottle of still or carbonated water) to replace
      the amount of SSBs they usually consume (≥1serving/day) as determined in the run-in phase.
      All intervention beverages will be provided to each participant. They will be instructed to
      replace their usual SSBs with the study beverages while freely consuming their usual
      background diets. The calories of the intervention groups will not be matched to allow for
      "real-world" substitutions using products available on the market. They will pick up one week
      of their beverage assignment at the first visit of each phase and then will have the
      remaining three weeks of beverages delivered using an online grocery delivery service. The
      participants will receive relevant drinks during the intervention phase based on their group
      assignment. They will revert to their usual SSB intake during wash-out phase during which
      they will not receive any beverages from the study.

      STATISTICAL ANALYSIS:

      Data will be analyzed according to an intention to treat (ITT) principle using mixed models
      in STATA 14 (StataCorp, Texas, USA). Sensitivity analysis will be performed on the basis of
      complete data availability for primary endpoints. A separate sensitivity analysis will be
      performed on the basis of antibiotic use during the trial.

        -  Primary outcomes. Repeated measures mixed effect models will be used to assess changes
           in the two primary outcomes i) beta diversity and ii) glucose iAUC between the groups.
           Pairwise comparisons between interventions will be performed using Tukey-Kramer
           adjustment or other appropriate statistics. For all primary outcomes effect modification
           by sex will be explored. The investigators will use the truncated Benjamini-Hochberg
           false discovery rate controlling method with parallel gatekeeping procedure to correct
           for multiple comparisons for all primary outcomes.

        -  Secondary outcomes. Repeated measures mixed effect models be used to assess changes in
           weight, waist circumference, fasting glucose, 2hr plasma glucose, and MATSUDA. Pairwise
           comparisons between interventions will be performed using Tukey-Kramer adjustment or
           other appropriate statistics. For all secondary outcomes effect modification by sex will
           be explored. The investigators will use the truncated Benjamini-Hochberg false discovery
           rate controlling method with parallel gatekeeping procedure to correct for multiple
           comparisons for all secondary outcome comparisons if at least one primary outcome
           reaches significance. If none of the primary outcomes reach significance, the secondary
           outcomes will be analyzed as exploratory variables with no adjustment for false
           discovery rate.

        -  Exploratory and adherence outcomes. Repeated measures mixed effect models will be used
           to assess changes in all exploratory outcomes without controlling for false discovery
           rate. Pairwise comparisons between interventions will be performed using Tukey-Kramer
           adjustment or other appropriate statistics. Effect modification by sex will be explored.

      OUTCOMES:

        -  The two primary outcomes are change in gut microbiome beta diversity, measured by 16S
           rRNA gene sequencing, and plasma glucose iAUC, measured by OGTT.

        -  Secondary outcomes are change in waist circumference, body weight, fasting plasma
           glucose, 2h plasma glucose [2h-PG], and the Matsuda whole body insulin sensitivity index
           [Matsuda ISIOGTT].

        -  Exploratory outcomes (specified below as "Other Pre-specified Outcome Measures")
           represent a comprehensive but non-exhaustive list of potential outcomes to be assessed
           which will be conducted on an ad hoc basis depending on the availability of funding.
           These include change in ectopic fat (an early metabolic lesion) in liver
           (intra-hepatocellular lipid [IHCL]) and calf muscles (intra-myocellular lipid [IMCL]) by
           1H-MRS; fasting plasma insulin; 75g OGTT derived indices (iAUC plasma insulin, maximum
           concentrations (Cmax) and time to maximum concentrations (Tmax) of plasma glucose and
           insulin, and mean incremental plasma glucose and insulin); homeostatic model assessment
           of insulin resistance (HOMA IR); the insulin secretion-sensitivity index-2 [ISSI-2]);
           fasting blood lipid profile; satiety, hunger, and food cravings (using the Control of
           Eating Questionnaire); diet quality (by analysis of the 3DDRs); and cardiometabolic risk
           (systolic and diastolic blood pressure, lipid profile (LDL, HDL, non-HDL cholesterol,
           total cholesterol), CRP, urinary sodium, liver function/injury (ALT, AST, ALP, TBIL),
           and kidney function/injury (albumin-to-creatinine ratio [ACR], creatinine, eGFR)),
           metabolomics, and proteomics.

        -  Adherence outcomes will be based on participant beverage logs, returned beverage
           containers, and objective biomarkers of SSBs (increased 13C/12C ratios in serum fatty
           acids, increased urinary fructose), water (decreased 13C/12C ratios in serum fatty
           acids, decreased urinary fructose), and NSBs (increased urinary acesulfame potassium,
           sucralose) intake.
    

Intervention name(s): Sugar-sweetened beverage (SSB); Non-nutritive sweetened beverages (NSB); Water
Intervention type(s): Other; Other; Other
Intervention description(s): SSBs will be provided to each participant. Participants will be able to choose their SSB of choice from the list in the protocol. They will be instructed to drink their usual SSB intake, study drinks provided, while freely consume their usual background diets. They will revert to their usual SSB intake during wash-out phase during which they will not receive any beverage drinks from the study.; NSBs will be provided to each participant. Participants will be be given the NSB equivalent to the usual SSB chosen from the list in the protocol. They will be instructed to replace their usual SSBs with the NSBs while freely consume their usual background diets. They will revert to their usual SSB intake during wash-out phase during which they will not receive any beverage drinks from the study.; Water will be provided to each participant. They will be instructed to replace their usual SSBs with the water while freely consume their usual background diets. They will revert to their usual SSB intake during wash-out phase during which they will not receive any beverage drinks from the study.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention
Keywords: Microbiome; Sugar Sweetened Beverages; Diet Beverages; Non-Nutritive Sweetened Beverages; Glucose response