The Effects of an 8-week Vegan Diet on TMAO Levels and Post-challenge Glucose Levels in Individuals With Dysglycaemia
Condition: Diabetes Mellitus, Type 2; Heart Diseases
MeSH terms: Heart Diseases; Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      The amount of people with diabetes mellitus has now reached over 4 million in the United
      Kingdom. Type 2 diabetes accounts for the majority of all cases of diabetes and increases the
      risk of many other diseases such as heart problems. Plant based diets are thought to be an
      effective way to improve markers of health related to type 2 diabetes and heart disease. One
      way that a plant based diet improves health could be through reducing waste products that are
      generated in the gut by the bacteria that break down food as part of the digestion process.
      For example, the digestion of some meats, fish and eggs results in the creation of a
      substance called Trimethylamine-N-Oxide (TMAO) which has been linked to worse health outcomes
      in several studies. However, the full impact on TMAO and blood glucose levels of swapping
      regular meat consumption for a plant based vegan diet is not fully understood and requires
      further research. Therefore, the aim of this study will be to develop and undertake a
      clinical trial to investigate the effects of an 8-week vegan diet on TMAO levels and post
      challenge glucose levels in individuals with dysglycaemia (drug naïve).

      The study will be interventional single group prospective trial of adults aged 18-75 years of
      age from a multi-ethnic population with dysglycaemia (drug naïve). A sample of 29 people will
      be sought. The dietary intervention (vegan diet) will last 8 weeks. Then, the participants
      will go back to their normal diet and come for their final visit after a four week follow-up
      period (week 12). To assess the effectiveness of the intervention, primary and secondary
      outcome data collected at baseline will be compared with data collected at 1 week, 8 weeks
      and 12 weeks.
    

Detailed description: 
      Study Design

      Interventional single group prospective trial in a patient population with identified
      dysglycaemia within the past 36 months defined as 2h post-challenge glucose ≥7.8 mmol/L after
      a standard oral glucose tolerance test or HbA1c ≥5.7% (39-46 mmol/mol). This phase clinical
      trial will evaluate the efficacy and underlining mechanisms of a vegan diet in promoting
      cardiometabolic health in those with dysglycaemia. Specifically, this trial will aim to
      investigate the effect of an 8-week vegan diet with follow-up at 1, 8 and 12 weeks.

      Study Setting

      The study will be co-ordinated within the Leicester Biomedical Research Centre (Leicester
      Diabetes Centre) at the Leicester General Hospital. Clinical measurement sessions will be
      carried out by the appointed research team. Participants will be asked to visit the study
      centre on five occasions.

      Intervention Description and Definition

      The participants will be asked to follow a diet that excludes foods hypothesised to support
      the syntheses of TMAO, particularly meat (any), eggs and fish (any). A number of studies
      suggest that dairy products may also have an effect in modulating TMAO production whereas
      other studies do not. Therefore, in order to avoid any potential contaminating or confounding
      effect, dairy products will also be avoided.

      The diet employed in this study is broadly aligned to a vegan diet. The term vegan will be
      used to aid behaviour change and food choice. For example, an increasing array of products
      are now pack marked as vegan. The participants will be asked to keep their diet similar to
      their original and the Registered Dietitian involved in this study will plan their weekly
      menus accordingly.
    

Intervention name(s): Adoption of a vegan diet
Intervention type(s): Other
Intervention description(s): Adoption of a vegan diet The participants of this study wil be asked to adopt a vegan diet under the supervision of a Registered Dietitian.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: type 2 diabetes; vegan diet; TMAO; cardiovascular disease