Effects of Consuming Red Meat on the Gut Microbiota in Young Adults
Condition: Diet Modification
Study type: Interventional

Summary: 
      The purpose of this study is to assess the impact of consuming unprocessed and processed red
      meat on gut microbiota in young healthy adults in a cross-over, randomized controlled feeding
      trial.
    

Detailed description: 
      The purpose of this study is to assess the impact of consuming processed and unprocessed red
      meat on gut microbiota in young healthy adults in a cross-over, randomized controlled feeding
      trial. The hypothesis is that compared to consuming a meat-free lacto-ovo vegetarian (LOV)
      diet, (1) consuming the LOV diet with unprocessed red meat or processed red meat (omnivorous
      diet) will shift the gut microbiota with greater abundance of the bacteria Lactobacillus and
      other SCFA producers such as Clostridium XIVa, and no increase of pathogenic bacteria. The
      concentration of SCFA in stools will also increase in subjects consuming the unprocessed red
      meat diet. Compared to consuming a meat-free lacto-ovo vegetarian (LOV) diet, (2) consuming
      the LOV diet with processed beef and pork (omnivorous diet) will result in a comparable shift
      in gut microbiota as unprocessed red meat, except for greater abundance of taxa
      Erysipelotrichaceae and lower abundance of Lachnospiraceae.
    

Intervention name(s): Controlled Lacto-ovo vegetarian diet; Controlled Unprocessed red meat diet; Controlled processed red meat diet
Intervention type(s): Other; Other; Other
Intervention description(s): Subjects will be randomized and assigned into an intervention to consume the controlled lacto-ovo vegetarian (LOV) diet for 3 weeks. All foods will be provided to subjects during the intervention. Each subject's energy requirement will be estimated using sex-specific equations published by the Institute of Medicine for weight maintenance during the intervention.; The unprocessed red meat diet will be the same as the LOV diet except that one 3-ounce portion of unprocessed red meat per day, 7 days per week (21 oz/wk) will be included. The unprocessed red meat will include beef tenderloin and pork loin. All foods will be provided to subjects during the intervention.; The processed red meat diet will be the same as the LOV diet except that one 3-ounce portion of processed red meat per day, 7 days per week (21 oz/wk) will be included. The processed red meat will include a variety of beef and pork luncheon meats with different methods of preservation. All foods will be provided to subjects during the intervention.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This is a 24-week randomized controlled, crossover, single-blind study. Following a 5-wk pre-intervention baseline period, subjects will be randomly assigned to consume a controlled diet that either does not contain any red meat (lacto-ovo vegetarian, LOV), or contains unprocessed lean red meat, or contains processed lean red meat, for 3 weeks. After a 5-week dietary 'washout' period, they will consume one of the alternative diets for 3 weeks. After the second 5-week dietary 'washout' period, they will consume the remaining alternative diet for 3 weeks. Stool and fasting-state blood samples will be obtained at the end of study weeks 3, 4, 7, 8, 11, 12, 15, 16, 19, 20, 23, and 24, which correspond to before and during the last 2 weeks of the three 3-wk controlled diet periods. Consecutive 4-day 24-hour urine samples will be collected within the assessment weeks of each dietary 'washout' period and control diet period (study weeks 4, 8, 12, 16, 20, 24).
Masking: Single (Outcomes Assessor)
Primary purpose: Other
Keywords: beef; pork; red meat; gut microbiota