Plant-Based Diet for Colorectal Cancer Prevention

(BILMOD Trial)

Overseen By Andrew T. Chan, MD, MPH

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Massachusetts General Hospital

Must not be taking: Anticoagulants, Aspirin, Antibiotics, Probiotics

Disqualifiers: Vegan, IBD, Cancer, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 7

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how a diet rich in plant-based foods and low in animal-based foods affects the body, focusing on gut health and factors linked to colon cancer. The researchers aim to determine if dietary changes can impact bile acids and other markers related to cancer risk. Ideal candidates have had a colonoscopy that found and removed at least one adenoma (a type of growth that can lead to cancer) and typically consume a Western diet high in animal products. As an unphased trial, this study provides a unique opportunity to contribute to understanding the health benefits of dietary changes.

Will I have to stop taking my current medications?

The trial requires that you stop taking certain medications, such as anticoagulants (blood thinners), aspirin, antibiotics, and probiotics. If you are on these medications and cannot stop, you may not be eligible to participate.

What prior data suggests that this dietary intervention is safe?

Research has shown that plant-based diets are generally safe and might help protect against some types of cancer. For instance, studies have found that people who follow a plant-based diet can have a significantly lower risk of developing colorectal cancer. One study reported up to an 88% lower risk, while another found a 28% reduction in risk with a healthy plant-based diet.

Switching to a plant-based diet usually involves eating more fruits, vegetables, and whole grains, which most people tolerate well. No major reports have linked negative effects directly to plant-based diets in cancer prevention. This suggests that the dietary changes in this trial are likely safe for participants. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about using a plant-based diet for preventing colorectal cancer because it offers a natural, non-invasive approach that focuses on dietary changes. Unlike traditional treatments like surgery, chemotherapy, or radiation, which can be harsh and come with significant side effects, a plant-based diet encourages the consumption of fruits, vegetables, and whole grains while reducing animal products. This dietary shift could potentially lower cancer risk by promoting gut health and reducing inflammation. By targeting the root cause—lifestyle and diet—this approach could not only prevent cancer but also improve overall health.

What evidence suggests that this dietary intervention could be effective for colorectal cancer prevention?

Research has shown that eating a plant-based diet can greatly reduce the risk of colorectal cancer. Studies have found that people who follow a plant-based diet have a 46% lower risk of colon cancer and a 73% lower risk of rectal cancer. Another study found that a healthy plant-based diet can lower the risk of colorectal cancer by 28%. This diet involves eating more foods from plants and fewer from animals. Overall, choosing a plant-based diet may strongly help prevent colorectal cancer. Participants in this trial will increase plant-based foods and decrease animal-based foods for a 4-week period. ^{3 4 5 6 7}

Who Is on the Research Team?

Andrew T. Chan, MD, MPH

Principal Investigator

Massachusetts General Hospital

Are You a Good Fit for This Trial?

This trial is for adults who are overweight or obese and at risk of colorectal cancer, possibly due to a history of colorectal adenomas. Participants should be willing to change their diet by eating more plants and fewer animal products.

Inclusion Criteria

Habitually consume a Western pattern diet

BMI of at least 18.5 kg/m2 but less than 35 kg/m2

Weight stable in last 3 months (loss or gain <4%)

Exclusion Criteria

Pregnant or breastfeeding

Strict dietary patterns (e.g., vegan, carnivore, kosher, low-carb etc.)

Known bleeding tendency/condition (e.g. von Willebrand disease) or history of peptic ulcer or gastrointestinal bleed requiring hospitalization, endoscopic complications, or contraindication to colonoscopy

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Observation

1 week of observation prior to dietary intervention to establish baseline food diary data

1 week

No visits, food diary entries every 2 days

Dietary Intervention

Participants increase plant-based food intake and decrease animal-based food intake

4 weeks

2 visits (in-person), phone calls for guidance, food diary entries every 2 days, stool sample collection every 7 days

Follow-up

Participants are monitored for changes in stool metabolomics, gut microbiome, and circulating biomarkers

5 weeks

2 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Increased Plant-Based Diet and Decreased Animal-Based Diet

Trial Overview The study tests whether changing your diet to include more plant-based foods and less meat can affect bile acid production in the gut, alter the types of bacteria living there, influence blood markers, and modify gene activity related to colon bile acid receptors and cancer risk.

How Is the Trial Designed?

Group I: Increased Plant-Based Diet and Decreased Animal-Based Diet Experimental Treatment 1 Intervention

Participants will be instructed to self-regulate their diet by increasing the amount of plant-based foods while decreasing the amount of animal-based foods for a 4-week period.

Who Is Running the Clinical Trial?

Massachusetts General Hospital

Lead Sponsor

Trials

3,066

Recruited

13,430,000+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9398226/

Healthy and unhealthy plant‐based diets in relation to ... It is estimated that eliminating the effect of poor‐quality diet in the United States may reduce colorectal cancer (CRC) incidence by approximately 38%.

2. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1091255X25002914

Plant-based diet and colorectal cancer: a systematic review ... A United States cohort study found that a healthy PBD was associated with a 28% reduction in CRC risk, whereas an unhealthy PBD was associated with a 41% ...

3. frontiersin.org frontiersin.org/journals/public-health/articles/10.3389/fpubh.2022.892153/full

The Relationship Between Plant-Based Diet and Risk of ... Conclusions: Plant-based diets were protective against cancers of the digestive system, with no significant differences between different types of cancer.

4. jhpn.biomedcentral.com jhpn.biomedcentral.com/articles/10.1186/s41043-024-00605-4

A healthful plant-based diet can reduce the risk of developing ... For instance, one study showed following a plant-based diet was linked to a 46% reduced risk of colon cancer and a 73% reduced risk of rectal ...

5. juniperpublishers.com juniperpublishers.com/ctoij/CTOIJ.MS.ID.555906.php

Colorectal Cancer Prevention with a Plant-Based Diet A Canadian study showed that a plant-based diet resulted in a 46% decreased risk of colon cancer and 73% decreased risk of rectal cancer [7].

6. translational-medicine.biomedcentral.com translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-04522-8

Plant-based dietary patterns, genetic predisposition and risk of ... Our results suggested that better adherence to overall and healthful plant-based diets was associated with a lower risk of CRC.

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10538608/

Vegetarian diets and the risk of gastrointestinal cancers Vegetarian diets were negatively correlated with the risk of gastrointestinal tumorigenesis in North American [RR = 0.76, 95% CI (0.61–0.95)] ...