The InterSat Study
Condition: Cardiometabolic Health
Study type: Interventional

Summary: 
      In response to the removal of trans fats from our foods, the food industry now uses
      interesterified (IE) fats. Randomly interesterified (IE) fats rich in palmitic (Europe) and
      stearic (North America) acids are the most commonly used IE fats by the food industry.
      Despite their widespread use, there has been no published research on the acute and chronic
      cardio-metabolic health effects of the most commonly consumed palmitic and stearic acid rich
      IE fats. The aim of InterSat is to investigate the postprandial and chronic effects of a diet
      rich in IE fats on cardiometabolic health.
    

Detailed description: 
      Choice of design: A randomised crossover study with two arms, each arm consisting of a 6-week
      dietary intervention, separated by a 3-week (minimum) washout period.

      Study population: Healthy adult snackers aged 35-65 years. 48 participants in total, 24 at
      each centre (see Locations).

      Locations:

      Metabolic Research Unit, Franklin-Wilkins Building, Waterloo Campus, King College London.

      Metabolic Research Unit Maastricht, Academic Hospital Maastricht, Maastricht University.

      Screening Assessment: Prospective participants will be selected based on the defined
      inclusion and exclusion criteria by the study management team. Recruitment will be done over
      the phone and via the Internet and emails and prospective participants will be booked in for
      their initial appointment to acquire baseline measurements.

      Study duration: A 2-week run-in period, two 6-week dietary interventions, and a 3-week
      (minimum) washout period.

      Dietary intervention: The InterSat intervention aims to provide 10% of total daily energy
      intake in the form of IE fat. These will be consumed in the form of muffins and spreads,
      designed to replace typically consumed snacks and spreads throughout the day. Energy
      requirements will be calculated using the Henry equation and physical activity levels (PAL).

      At the baseline visit, participants will have and anthropometric measures and fasted blood
      samples taken, and will be assessed for endothelial function via flow mediated dilation
      (FMD), after which they will be provided with enough muffins and spread for a 2-week period,
      as well a study booklet (containing instructions and a diary to log muffin and spread
      consumption). They will receive guidance on how to incorporate the muffins and spread into
      their diet. Food collection dates will be set, and participants are then free to leave. At
      the second visit (first snack collection visit), no physical measures are taken, but the
      empty tubs and muffin cases are collected, and the study booklet is checked by a researcher
      to ensure the participant is compliant to the intervention. Any issues should be discussed,
      and guidance given to increase compliance if necessary. Another snack collection visit is
      booked. At the end of the 6-week intervention, participants will undergo physical and blood
      sampling as well as FMD, as with the baseline testing day. After a 3-week (minimum) washout
      period, the same procedures occur for the other arm of the trial.

      Anthropometry: Weight, height, waist and hip circumference, blood pressure, body fat will be
      taken using standard procedures, in duplicates by a trained researcher at all face to face
      appointments.

      Habitual food intake: Participants will complete the EPIC (European prospective investigation
      of cancer) food frequency questionnaire at the screening visit. They will also complete three
      4-day diet diaries (one at the run-in period and one in each of the dietary intervention
      periods).

      Blood samples: Fasting blood samples will be collected from a superficial antecubital vein
      via venepuncture before and after each dietary intervention. Postprandial blood samples will
      be taken via cannulation in a subgroup (see Subgroup below) for an 8-hour postprandial test
      day.

      Participants will be asked to record and monitor the following information:

      Amount of muffins and spread consumed (study booklet). Habitual intake (4-day diet diaries).

      Subgroup: A subset (n = 24) of participants will undergo a postprandial test day at the
      baseline and 6-week points of each intervention arm. After baseline samples (anthropometrics,
      blood samples, FMD) are taken, participants will consume a breakfast containing a large bolus
      of the IE fat they are assigned to. Blood samples will be taken over an 8-hour testing period
      and FMD will be taken 2 more times. Liver fat will be assessed via MRI imaging (Maastricht
      only).
    

Intervention name(s): Palmitic acid rich interesterified fat; Stearic acid rich interesterified fat
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Muffins and spread containing the palmitic acid rich IE fat will be consumed daily for a 6-week dietary intervention period; Muffins and spread containing the palmitic acid rich IE fat will be consumed daily for a 6-week dietary intervention period.
Intervention MeSH terms: Palmitic Acid
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Randomised controlled trial with 2x6 week interventions separated by a 3 week washout.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Interesterified fat; Cardiometabolic health; Palmitic acid; Stearic acid; Vascular function; Postprandial lipaemia