PREDICT 2: Personalized Responses to Dietary Composition Trial 2
Condition: Diabetes; Heart Diseases; Diet Habit; Diet Modification; Microbial Colonization; Healthy; Obesity; Metabolism
MeSH terms: Communicable Diseases; Infections; Heart Diseases
Study type: Interventional

Summary: 
      Foods in the human diet can affect the development of diseases over time, such as diabetes or
      heart disease. This is because the amount and types of foods in the diet eat can affect a
      person's weight, and because different foods are metabolised (processed) by the body in
      different ways.

      Scientists have also found that the bacteria in the human gut (the gut microbiome) affect
      their metabolism, weight and health and that, together with a person's diet and metabolism,
      could be used to predict appetite and how meals affect the levels of sugar (glucose) and fats
      (lipids) found in blood after eating. If blood sugar and fat are too high too often for too
      long, there is a greater chance of developing diseases such as diabetes and cardiovascular
      disease.

      The gut microbiome is different in different people. Only 10-20% of the types of bacteria
      found in the human gut are found in everyone. This might mean that the best diet to prevent
      disease needs matching to a person's gut microbiome and it might be possible to find
      personalised foods or diets that will help reduce the chance of developing chronic disease as
      well as metabolic syndrome.

      The study investigators are recruiting volunteers aged 18-70 years to take part in a study
      that aims to answer the questions above. Participants will be asked to consume standardised
      meals on up to 8 days while wearing glucose monitors (Abbott Freestyle Libre) to measure
      their blood sugar levels. Participants will also be required to prick their fingers at
      regular intervals to collect small amounts of blood, and to record their appetite, food,
      physical activity and sleep using apps and wearable devices. They will be asked to collect a
      fecal and saliva sample before consuming the standardised meals, and to provide a fasted
      blood sample at the end of the study period.
    

Detailed description: 
      Choice of design: The study is a single arm mechanistic intervention study.

      Study population: Participants will be recruited through online and offline advertisements,
      and through health professionals.

      Screening Assessment: Prospective participants will be selected based on the defined
      inclusion and exclusion criteria by the study management team. Screening will be online and
      via phone. Prospective participants will be booked in to start their study period and will
      receive a study kit by post.

      Study duration: Each participant will take part in the study for a period of up to 12 days.

      Dietary intervention: The dietary intervention will be carried out on up to 8 days within the
      12-day study period. On day one, participants will be asked to collect biological samples and
      fit wearable devices (glucose monitor and physical activity tracker). Over the following
      consecutive days, each participant will be instructed to eat up to 8 standardised meals for
      breakfast, which must be their first meal of the day. On up to 3 of the days the participants
      will also be asked to eat a standardised lunch. Participants are free to eat whatever they
      wish at all other times. The standardised meals will be provided to all participants by the
      study team via post. The foods included as part of these meals will be foods that are
      commonly consumed and can be made from products sold in US supermarkets. Participants will be
      reassured that the amount of food will be designed to ensure a stable body weight over the
      course of the study. Participants will be asked to consume the entire amount of food
      indicated for the standardised meals and to record any left-over food via a digital app for
      which training will be provided at the start of the study. Following completion of
      standardised meal days, participants are free to eat and drink whatever they wish and will be
      asked to track all meals, snacks and drinks on their digital app. Participants will also be
      advised not to change their physical activity patterns during the course of the study. The
      12th day of the study involves a visit to a medical clinic where participants will provide a
      fasted blood sample.

      Regular contact will be made with the participants via phone, their app and text messages for
      the period of the intervention to encourage compliance and answer any queries.

      Anthropometry: The participant will be instructed to measure their weight, height, waist and
      hip circumference.

      Dietary and Lifestyle: Participants will be asked to complete a baseline questionnaire
      online, as well as a diet history questionnaire with portion sizes about the month preceding
      their study period. They will be asked to record on a daily basis their dietary, activity,
      and psychological data (e.g. hunger) using a digital mobile phone app. Lifestyle information
      (such as sleep and exercise) will be monitored using digital wearable devices. Training in
      all apps and equipment will be given through written and online instructions and via
      communications with the study support staff.

      Digital devices: Participants will be asked to record daily dietary and activity information
      using digital apps and lifestyle information will be monitored using digital wearable
      devices. The continuous glucose monitor (Freestyle Libre, CGM) provides continuous glucose
      profiles for up to 14 days. The CGM will be inserted on the back of the upper arm, one day
      before participants begin dietary intervention. This will measure subcutaneous interstitial
      fluid glucose concentrations every 5 minutes. The CGM will be removed at the end of the
      intervention period by the participant. A contact number will be made available to
      participants for any inquiries or if any problems arise. Data from the CGM will be
      downloaded, and glucose profiles will be evaluated on the basis of data collected.

      Blood samples: The participant will collect postprandial blood on 2 days using finger-prick
      blood sampling. They will also provide a fasted blood sample after the study period to
      measure their baseline metabolomic profile.

      Digital app: Participants will be asked to download an app designed specifically for this
      study, which provides diet & activity logging functionality similar to widely used existing
      apps such as MyFitnessPal.

      Participants will be asked to record and monitor the following information via the digital
      app and wearable devices, on a daily basis:

        -  All food and drink they consume, with serving sizes and photos

        -  Sleep and physical activity patterns, including exercise

        -  Hunger and alertness ratings

        -  Psychological feeling of energy and mood

        -  Prescription and over-the-counter drug consumption

      The app will be available in versions for both iOS and Android operating systems, and will
      support a wide range of mobile phone models as expected across the participant population.
      The app will synchronise remotely with backend database servers, over an encrypted and
      authenticated API, and will support offline operation for when patients wish to record an
      entry without network coverage. This continuous background synchronization means that it will
      not be necessary to explicitly download data from the phone at the end of the study.

      Following the 2020 pandemic of COVID-19, participants are asked to use the COVID-19 Symptom
      Tracker app to record their physical health symptoms, or lack thereof, attributable to
      COVID-19, as well as demographic and other health information to track the spread of disease
      in real time, and to potentially reveal risk factors for infection and severe illness.

      Subcohort: An opt-in follow-on study will be offered to participants to follow dietary
      guidance from the ZOE app based on their Predict 2 results. During the first 2 to 4 weeks,
      participants will be given dietary guidance to follow from the ZOE app. Thereafter, for a
      period of up to 12 months, participants will be asked to report on outcome measures at
      regular intervals (monthly). Outcome measures will be reported before, during and after the 2
      to 4 week period and include weight, bristol stool, bowel habits, hunger, energy, alertness,
      stress, mood, activity, adherence to dietary advice, and app usage.

      The data will be used to test the efficacy of the ZOE dietary advice in promoting weight loss
      and improvement of overall health, and may be stratified by age, sex, BMI, adherence and/or
      motivation to take part in the PREDICT 2 study.
    

Intervention name(s): Dietary Intervention
Intervention type(s): Other
Intervention description(s): To carry out an interventional dietary study using standardised meals to predict an individual's metabolic response to certain foods, using their gut microbiome, metabolic profile, and other measurable characteristics such as weight, sleep and exercise.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Gut microbiome; Personalised Nutrition; Metabolic health; Postprandial metabolism