Effects of Brassica on Human Gut Lactobacilli
Condition: Human Gut Microbiota
Study type: Interventional

Summary: 
      Brassica vegetables are an important part of the investigators normal diet and are associated
      with a reduced risk of many chronic diseases. The protective effect may be as a result of the
      hydrolytic products of compounds contained within these vegetables, called glucosinolates.
      There is evidence that consumption of Brassica vegetables may cause compositional changes to
      the investigators gut microbiota. The aim of this study is to see whether a diet rich in
      Brassica alters the human gut microbiota composition, and specifically whether it causes an
      increase in the number of the beneficial bacteria known as lactobacilli.
    

Detailed description: 
      The study is a randomised human dietary intervention two-phase cross-over study and will
      require the participants to consume both a low and a high Brassica vegetable diet. In this
      study, male and female participants aged between 18 and 50 years will be recruited until 10
      complete the study. For the low Brassica diet test phase, the participants will be provided
      with one 84g portion of frozen broccoli and one 84g portion of frozen cauliflower, to be
      consumed across a period of two weeks. The participants will be asked to consume one of these
      portions of Brassica (either broccoli or cauliflower) in week one, and then consume the
      remaining portion of Brassica in week two, with a minimum of 5 days between consuming the two
      portions. When on the high Brassica diet test phase, the participants will be provided with
      six 84g portions of frozen broccoli, six 84g portions of frozen cauliflower, and six 300g
      portions of frozen broccoli and sweet potato soups (each with a broccoli content of 84g), to
      be consumed across a period of two weeks. The participants will be asked to consume three
      portions of broccoli, three portions of cauliflower, and three portions of the broccoli and
      sweet potato soups each week for two weeks, consuming a minimum of one portion per day. The
      Brassica diet test phases will be separated by a washout period, which will be a minimum of 2
      weeks.

      The participants will be asked to restrict their diet of Brassica vegetables and
      ITC-containing foods for a period which includes 2 weeks prior to test phases 1 and 2, as
      well as during the full 2 weeks of each test phase. The participants will be asked to provide
      faecal samples, urine samples, complete food diaries and stool charts at various stages
      throughout the intervention. Participants will be asked to complete a food diary, recording
      the consumption of all fruits and vegetables, for a consecutive seven day period, during each
      of the two test phases (test phases 1 and 2), and for the entire seven days of the last week
      of the study when consuming their habitual diet. Participants will also need to be willing to
      complete stool charts noting the frequency and consistency of their bowel movements.
    

Intervention name(s): High Brassica; Low Brassica
Intervention type(s): Other; Other
Intervention description(s): Participants consume a minimum of one portion of a Brassica food (84g frozen broccoli, 84g frozen cauliflower, or 300g frozen broccoli and sweet potato soup) each day for 14 consecutive days at their homes.; Participants consume one portion of a Brassica vegetable (84g frozen broccoli, or 84g frozen cauliflower) each week for two weeks at their homes.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science