Effects of Lactose on Fecal Microflora
Condition: Lactose Intolerance
MeSH terms: Lactose Intolerance
Study type: Interventional

Summary: 
      The genetics of lactase divides the population into 2 phenotypes: Those who can(LP) and those
      who cannot(LNP)digest lactose. This division may help modify disease risks according to
      geographic population distribution. At least some of the putative mechanism of risk
      modification may relate to an effect of undigested lactose on lower intestinal bacteria. The
      effect may provide for support of beneficial microbes. The amount of lactose reaching the
      colon is made easier in LNP than LP subjects who have to consume larger amounts to have
      meaningful spillover into the lower bowel.The current study examines whether there are
      quantifiable qualitative fecal bacterial differences to a standard intake of lactose(milk
      sugar)between these 2 different phenotypic populations. Finding of differences would lend
      support to the notion that for some diseases LP and LNP subjects face different risks even in
      an area of uniform disease risk if they consume lactose (found in dairy foods).

      The primary end point is comparison of 4 groups of specific bacteria between LP and LNP
      participants before and after 2 weeks of lactose(in powder form mixed in water) consumption.
      Classification is based on genetic analysis and secondarily on breath hydrogen results.
      Results are compared within groups.

      The secondary outcome is comparison of 4 groups of bacteria between LP and LNP subjects
      against each group of stool samples obtained on the first visit. Results are obtained between
      groups.

      Additional information and other secondary outcomes are to evaluate any relationship between
      diet intake and the 4 groups of bacteria on the first visit

      Another outcome will be to compare within groups any effect of lactose consumption on insulin
      and glucose levels within the 2 groups.
    

Detailed description: 
      Healthy volunteers between the ages of 18 and 49 are recruited.

        1. Each participant fills a lactose targetting diet questionnaire(3 day recall).

        2. A 50g lactose challenge tets is administered,breath hydrogen and symptoms are recorded
           for 4.5hrs.

        3. Blood is drawn for analysis of lactase genetic status.

        4. A stool sample is collected(10-15g)and analysed fo total anaerobes, enterococci,
           bifidobacteria and lactobacilli.

        5. All subjects are withdrawn from dairy foods(calcium replacement suggested in diet) for 2
           weeks and are aked to return to repeat parts 2 and 4.

        6. A voluntary segment has glucose and insulin measured for 4 hrs via an indwelling venous
           catheter.

        7. Subjects are asked to consume 50g lactose in divided doses for 2 further weeks

        8. At the end they return and repeat sections 2 and 4 for the third time.

        9. Participants who volunteered to have glucose and insulin measured repeat this segment of
           the study as well.
    

Intervention name(s): lactose; lactose
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): consumption of 50g lactose/day in 2 divided doses mixed in water.; consumption of lactose 50g/day in 2 divided doses mixed in water
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: lactase; lactose; microflora