Diet Modification
Conditions
Keywords
beef, pork, red meat, gut microbiota
Brief 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.
Interventions
OTHERControlled Lacto-ovo vegetarian diet
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.
OTHERControlled Unprocessed red meat diet
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.
OTHERControlled processed red meat diet
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.
Sponsors
Purdue University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Outcomes Assessor)
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).
Eligibility
Sex/Gender
ALL
Age
20 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* male or female, * 20-35 years old, * BMI 20.0-29.9 kg/m2, * fasting serum total cholesterol \<240 mg/dL, low-density lipoprotein cholesterol \<160 mg/dL, triglycerides \<400 mg/dL, and glucose \<110 mg/dL; * systolic/diastolic blood pressure \<140/90 mmHg; * body weight stable for 3 months prior (±3 kg); stable physical activity regimen 3 months prior; * medication use stable for 6 months prior and not using medications or supplements known to impact gut function; * on-smoking; not drinking more than 2 alcoholic drinks per day; * non-diabetic, * no history of gastrointestinal disorders, surgeries or cancers; * non-pregnant and not lactating. * Participants must be willing and able to consume the prescribed diets (lacto-ovo vegetarian and omnivorous).
Exclusion criteria
* male or female \< 20-\>35 years old, * BMI \<20.0- \>29.9 kg/m2, * fasting serum total cholesterol \>240 mg/dL, low-density lipoprotein cholesterol \>160 mg/dL, triglycerides \>400 mg/dL, and glucose \>110 mg/dL; * systolic/diastolic blood pressure \>140/90 mmHg; * body weight stable for \<3 months prior (±3 kg); * stable physical activity regimen \< 3 months prior; * medication use unstable for 6 months prior and using medications or supplements known to impact gut function; * smoking; * drinking more than 2 alcoholic drinks per day; * diabetic, * history of gastrointestinal disorders, GI surgeries or GI cancers; * pregnant or lactating.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in gut microbiota composition | 21 months. Stool 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. | 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. 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. |
| Concentrations of short chain fatty acids (SCFA) | 21 months. Stool 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. | The hypothesis is that compared to consuming a meat-free lacto-ovo vegetarian (LOV) diet, the concentration of SCFA in stools will also increase in subjects consuming the unprocessed or processed red meat diet. |
Other
| Measure | Time frame | Description |
|---|---|---|
| metabolomics analysis | Undecided. | Saves of blood, urine, and stool samples will be kept for possible further metabolomics and foodomics analyses. |
Countries
United States
Outcome results
None listed