DysbiosisEarly Phase 1NCT05658263
Bacterial Intestinal Gut Modification Around Cancer Surgery (BIG MACS) Diet
A Early Phase 1 study testing Standard Diet and BIG MACS Diet in people with Dysbiosis and Sarcopenia, run by University of Minnesota at 1 site in United States.
Trial summary
The long-term study objective is to develop optimized nutritional therapies for surgery and test them in clinical practice. This pilot study will test a microbiome-optimization diet in colorectal cancer surgery patients. Read more about this study
- Who is it for?
- Ages 25 to 70 years
- Conditions the study is for
- Dysbiosis, Sarcopenia, Colon Cancer
- What is being tested?
- Standard Diet and BIG MACS Diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Jan 2023to 15 Aug 2024
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age 25-70 years
- Primary diagnosis of colon cancer, stages 1-3.
- Able and willing to provide informed consent.
- English-speaking.
- Willingness to return to the study site for specified study visits at D7 and D30.
- Able to comply with study measures.
Who cannot join
- Age ≤ 25 years or ≥70 years
- If surgery is being performed for any reason other than resection of colon cancer. Neoadjuvant therapy, or if surgery is not the initial approach for the patient's colon cancer treatment
- Significant anemia (hemoglobin 1.0 g/dL or more below normal range) or history of coagulopathy: any personal history of hereditary or acquired bleeding disorder, or thrombocytopenia with platelets under 100,000.
- Serum creatinine greater than 1.5 mg/dL.
- Serum total bilirubin greater than the upper limit of normal in the absence of Gilbert's syndrome or alkaline phosphatase or ALT or AST greater than 2.5 times the upper limit of normal. Elevated INR (1.5 or above).
- Alcohol intake more than one drink or greater than 20 grams per day for women or 30 grams per day for men.
Show all 21Show fewer
- History of gastrointestinal surgery including stomach, small bowel or colon resection, pancreatic surgery, bile duct or gallbladder surgery, or splenectomy, or gastric bypass.
- History of intra-abdominal sepsis.
- Previous organ transplantation.
- Self-reported HIV-positive status, active tuberculosis, active malaria, chronic hepatitis B or C, cirrhosis, or inflammatory bowel disease.
- Currently pregnant or nursing.
- History of alcohol, drug, or opioid dependency (excluding nicotine) in the past five years.
- Active psychosocial or psychiatric problem that is likely to interfere with adherence to the protocol.
- Depression: A CES-D score more than 16 and a psychologist determining that the patient is not a good fit for surgery.
- Body mass index (BMI) \<20 or \> 40 kilograms per meter squared:
- obesity is known to impact the microbiome and immune system and the occurrence of anastomotic leak, and extreme obesity may confound interpretation of these factors in association to leak. Inferences may be made by matching participants with less severe obesity (BMI \<40).
- Presence of any type of non-MRI compatible implant, including cardiac pacemakers or defibrillators, neurostimulators, cochlear implants, or other metallic hardware
- Self-reported history of claustrophobia.
- Incarceration
- Inability to adhere to the study protocol, procedures, and diet
- Exclusions may also be made at the discretion of the attending physician.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Minnesota
Minneapolis, Minnesota, 55455
About this study
The long-term study objective is to develop optimized nutritional therapies for surgery and test them in clinical practice. This pilot study will test a microbiome-optimization diet in colorectal cancer surgery patients. The study hypothesizes that the Bacterial Intestinal Gut Modification Around Cancer Surgery (BIG MACS) Diet will provide participants with increased microbiota accessible carbohydrates (MACs) to support the microbiome and improve outcomes.
- Conditions
- Dysbiosis, Sarcopenia, Colon Cancer
- Being tested
- Standard Diet, BIG MACS Diet
- Medical subject headings
- Dysbiosis, Sarcopenia, Colonic Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Standard DietDietary supplement
Participants receiving only standard of care (SOC) nutrition advice, which is SOC Dietary Instructions, as provided by routine surgical consults and one protein shake per day for 4 weeks prior to surgery (SOC).
BIG MACS DietDietary supplement
Participants will be instructed to consume the study diet, referred to as the 'BIG MACS Diet' and one protein shake per day for 4 weeks prior to surgery (SOC). Following surgery, participants will continue to follow the BIG MACS Diet for an additional four weeks, with solid food reintroduction after surgery as early as tolerated.
| Study group | Role | What they receive |
|---|---|---|
| Standard Diet | Active comparator | Participants receiving only standard of care (SOC) nutrition advice, which is SOC Dietary Instructions, as provided by routine surgical consults and one protein shake per day for 4 weeks prior to surgery (SOC). Receives: Dietary Supplement: Standard Diet |
| BIG MACS Diet | Experimental | Participants will be instructed to consume the study diet, referred to as the 'BIG MACS Diet' and one protein shake per day for 4 weeks prior to surgery (SOC). Following surgery, participants will continue to follow the BIG MACS Diet for an additional four weeks, with solid food reintroduction after surgery as early as tolerated. Receives: Dietary Supplement: BIG MACS Diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in muscle mass
The change in muscle mass assessed by MRI-measured area and density of the psoas muscle at the level of the L3 vertebra with adjunct grip strength measurement.
Measured: baseline and 4 weeks after surgery
Frequency of accidental gas leakage
this will be assessed in times per day or times per month
Measured: 4 weeks after surgery
Frequency of accidental mucus leakage
this will be assessed in times per day or times per month
Measured: 4 weeks after surgery
Frequency of accidental liquid stool leakage
this will be assessed in times per day or times per month
Measured: 4 weeks after surgery
Frequency of bowel movements
this will be assessed in numbers per day or numbers per week
Measured: 4 weeks after surgery
stool consistency
Bristol Stool Chart: Type 1 (hard lumps) through Type 7 (watery, no solid pieces, entirely liquid
Measured: 4 weeks after surgery
Bowel emptying patterns
(includes constipation, diarrhea, urgency; range: always--> never)
Measured: 4 weeks after surgery
Laxative/stool softener use
Yes/No
Measured: 4 weeks after surgery
Laxative/stool softener use
times/day
Measured: 4 weeks after surgery
Laxative/stool softener use
times/week
Measured: 4 weeks after surgery
Laxative/stool softener use
times/month
Measured: 4 weeks after surgery
Gastrointestinal comfort
range: 0 (no problem) --> 4 (very strong discomfort)
Measured: 24 hours before surgery
Bowel emptying patterns
includes constipation, diarrhea, urgency; range: 0 (never) --> 4 (always)
Measured: 24 hours before surgery
Laxative/stool softener use
range; 0-4+ doses
Measured: 24 hours before surgery
Compliance with the dietary intervention or standard of care- Baseline veggie meter
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Measured: baseline
Compliance with the dietary intervention or standard of care- Baseline veggie meter
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Measured: postop day 7
Compliance with the dietary intervention or standard of care- Baseline veggie meter
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Measured: postop day 30
Compliance with the dietary intervention or standard of care- survey
24-hour diet recall surveys conducted by Nutrition Coordinating Center at University of Minnesota
Measured: 4 weeks
Secondary outcomes (8)
Change in microbiome features- alpha diversity
Shannon, Simpson, and Chao1 indices
Measured: Baseline, time of surgery, postop day 7 and 30
Change in microbiome features- beta diversity
compositionally corrected Aitchison's distances
Measured: Baseline, time of surgery, postop day 7 and 30
Fecal metabolites
Targeted fecal and serum metabolomics will measure changes in short chain fatty acids (SCFAs) and bile acids.
Measured: baseline and 4 weeks after surgery
Fecal inflammatory markers
ELISA. Fecal calprotectin and IgA levels will be measured using ELISA as markers of intestinal inflammation.
Measured: Baseline and 4 weeks after surgery
Changes in body composition- abdominal muscle
total abdominal muscle area in cm squared. Absolute and relative change in total abdominal muscle area per patient over time (cm squared ), with the average change per patient group compared between study and control group
Measured: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- psoas muscle
total psoas muscle area in cm squared. Absolute and relative change in total psoas muscle area per patient over time (cm squared ), with the average change per patient group compared between study and control group
Measured: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- volume of fat
MRI-measured area (cm2) and volume (L) of subcutaneous and visceral adipose tissue
Measured: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- liver fat
MRI-measured liver fat content
Measured: Baseline, time of surgery, postop day 7 and 30
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Dec 2022
- Study start3 Jan 2023
- Primary completion15 Aug 2024
- Study completion15 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for DysbiosisStudies of the same condition, open and under way.
- More trials run by University of MinnesotaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Supportive care
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Minnesota
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Cyrus Jahansouz, Principal investigator, University of Minnesota
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05658263
- Sponsor's protocol ID
- SURG-2023-31051
- Status last verified
- May 2025
- First submitted
- 11 Oct 2022
- Last updated
- 13 May 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 13 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bacterial Intestinal Gut Modification Around Cancer Surgery (BIG MACS) Diet
- ClinicalTrials.gov ID
- NCT05658263
- Acronym / sponsor ID
- SURG-2023-31051
- Conditions
- Dysbiosis, Sarcopenia, Colon Cancer
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- University of MinnesotaUniversity, hospital or other
- Study start
- 3 Jan 2023 (actual)
- Primary completion
- 15 Aug 2024 (actual)
- Study completion
- 15 Aug 2024 (actual)
- First posted
- 20 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The long-term study objective is to develop optimized nutritional therapies for surgery and test them in clinical practice. This pilot study will test a microbiome-optimization diet in colorectal cancer surgery patients. The study hypothesizes that the Bacterial Intestinal Gut Modification Around Cancer Surgery (BIG MACS) Diet will provide participants with increased microbiota accessible carbohydrates (MACs) to support the microbiome and improve outcomes.
Study design
- Primary purpose
- Supportive care
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Standard Diet | Active comparator | Dietary Supplement: Standard DietParticipants receiving only standard of care (SOC) nutrition advice, which is SOC Dietary Instructions, as provided by routine surgical consults and one protein shake per day for 4 weeks prior to surgery (SOC). |
| BIG MACS Diet | Experimental | Dietary Supplement: BIG MACS DietParticipants will be instructed to consume the study diet, referred to as the 'BIG MACS Diet' and one protein shake per day for 4 weeks prior to surgery (SOC). Following surgery, participants will continue to follow the BIG MACS Diet for an additional four weeks, with solid food reintroduction after surgery as early as tolerated. |
Who may qualify
- Ages
- 25 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age 25-70 years
- Primary diagnosis of colon cancer, stages 1-3.
- Able and willing to provide informed consent.
- English-speaking.
- Willingness to return to the study site for specified study visits at D7 and D30.
Key exclusion criteria (21 listed)
- Age ≤ 25 years or ≥70 years
- If surgery is being performed for any reason other than resection of colon cancer. Neoadjuvant therapy, or if surgery is not the initial approach for the patient's colon cancer treatment
- Significant anemia (hemoglobin 1.0 g/dL or more below normal range) or history of coagulopathy: any personal history of hereditary or acquired bleeding disorder, or thrombocytopenia with platelets under 100,000.
- Serum creatinine greater than 1.5 mg/dL.
- Serum total bilirubin greater than the upper limit of normal in the absence of Gilbert's syndrome or alkaline phosphatase or ALT or AST greater than 2.5 times the upper limit of normal. Elevated INR (1.5 or above).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Standard DietParticipants receiving only standard of care (SOC) nutrition advice, which is SOC Dietary Instructions, as provided by routine surgical consults and one protein shake per day for 4 weeks prior to surgery (SOC). | Dietary supplement | Standard Diet |
| BIG MACS DietParticipants will be instructed to consume the study diet, referred to as the 'BIG MACS Diet' and one protein shake per day for 4 weeks prior to surgery (SOC). Following surgery, participants will continue to follow the BIG MACS Diet for an additional four weeks, with solid food reintroduction after surgery as early as tolerated. | Dietary supplement | BIG MACS Diet |
Primary outcome
Change in muscle mass
Time frame: baseline and 4 weeks after surgery
The change in muscle mass assessed by MRI-measured area and density of the psoas muscle at the level of the L3 vertebra with adjunct grip strength measurement.
Frequency of accidental gas leakage
Time frame: 4 weeks after surgery
this will be assessed in times per day or times per month
Frequency of accidental mucus leakage
Time frame: 4 weeks after surgery
this will be assessed in times per day or times per month
Frequency of accidental liquid stool leakage
Time frame: 4 weeks after surgery
this will be assessed in times per day or times per month
Frequency of bowel movements
Time frame: 4 weeks after surgery
this will be assessed in numbers per day or numbers per week
stool consistency
Time frame: 4 weeks after surgery
Bristol Stool Chart: Type 1 (hard lumps) through Type 7 (watery, no solid pieces, entirely liquid
Bowel emptying patterns
Time frame: 4 weeks after surgery
(includes constipation, diarrhea, urgency; range: always--> never)
Laxative/stool softener use
Time frame: 4 weeks after surgery
Yes/No
Laxative/stool softener use
Time frame: 4 weeks after surgery
times/day
Laxative/stool softener use
Time frame: 4 weeks after surgery
times/week
Laxative/stool softener use
Time frame: 4 weeks after surgery
times/month
Gastrointestinal comfort
Time frame: 24 hours before surgery
range: 0 (no problem) --> 4 (very strong discomfort)
Bowel emptying patterns
Time frame: 24 hours before surgery
includes constipation, diarrhea, urgency; range: 0 (never) --> 4 (always)
Laxative/stool softener use
Time frame: 24 hours before surgery
range; 0-4+ doses
Compliance with the dietary intervention or standard of care- Baseline veggie meter
Time frame: baseline
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Compliance with the dietary intervention or standard of care- Baseline veggie meter
Time frame: postop day 7
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Compliance with the dietary intervention or standard of care- Baseline veggie meter
Time frame: postop day 30
carotenoid score, triplicate measurement; range: 0 (lower estimated value)-800 (arbitrary units; higher estimated value correlates with greater carotenoid concentrations
Compliance with the dietary intervention or standard of care- survey
Time frame: 4 weeks
24-hour diet recall surveys conducted by Nutrition Coordinating Center at University of Minnesota
8 secondary outcomes
Change in microbiome features- alpha diversity
Time frame: Baseline, time of surgery, postop day 7 and 30
Change in microbiome features- beta diversity
Time frame: Baseline, time of surgery, postop day 7 and 30
Fecal metabolites
Time frame: baseline and 4 weeks after surgery
Fecal inflammatory markers
Time frame: Baseline and 4 weeks after surgery
Changes in body composition- abdominal muscle
Time frame: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- psoas muscle
Time frame: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- volume of fat
Time frame: Baseline, time of surgery, postop day 7 and 30
Changes in body composition- liver fat
Time frame: Baseline, time of surgery, postop day 7 and 30
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 May 2025.
- Individual participant dataSharing planned: Undecided
Related trials for Dysbiosis
Recruiting
Colon-delivered Riboflavin and Gut Microbiota Composition
Microbiome Dysbiosis, Gut Health
Enrolling by invitationPhase 2
Herbal Supplement (Biocidin REMOVE) for Bacterial Overgrowth in Irritable Bowel Syndrome
Irritable Bowel Syndrome (IBS), Small Intestinal Bacterial Overgrowth Syndrome (SIBO)
RecruitingObservational study
Effects Of Periodontal Therapy In Patients With Inflammatory Bowel Disease
Periodontal Diseases, IBD
Recruiting
Effect of a Probiotic or Postbiotic on Gut Microbiome During Antibiotic Treatment
Microbiome
RecruitingObservational study
Metabolic and Functional Study of γδ T Cells in Critically Ill Patients
Sepsis, Critical Illness
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Cyrus Jahansouz principal investigator
University of Minnesota
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Standard Diet and BIG MACS Diet in people with Dysbiosis and Sarcopenia, run by University of Minnesota at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in muscle mass (time frame: baseline and 4 weeks after surgery). The study lists 18 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 May 2025.