High Fiber Diet for Obesity and Colon Cancer

Overseen By Terry Hartman, PhD, MPH, RD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Emory University

Must not be taking: Anti-inflammatories, Gut-altering drugs

Disqualifiers: Colorectal cancer, Bowel resection, others

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

Compensation: Varies

Number of Visits: 6

60 Participants Needed

Trial Summary

Do I have to stop taking my current medications for the trial?

The trial does not specify if you must stop taking your current medications, but you cannot participate if you regularly use prescription medication that may alter inflammation markers or gut function.

Will I have to stop taking my current medications?

The trial excludes people who regularly or recently use prescription medication that may affect inflammation markers or gut function, so you might need to stop taking such medications. It's best to discuss your specific medications with the study team.

What data supports the idea that High Fiber Diet for Obesity and Colon Cancer is an effective treatment?

The available research shows that a high fiber diet can reduce the risk of colon cancer. Studies have found that switching from a diet high in fats to one rich in fiber and whole grains can lower the chances of developing colon cancer. Specifically, wheat bran has been shown to be more effective in preventing colon tumors than other fiber sources like oat or corn bran. Additionally, populations with higher fiber intake from cereals, fruits, and vegetables tend to have lower rates of colon cancer. Although some studies have mixed results, overall, increasing fiber intake is recommended as it may help reduce cancer rates. ^{1 2 3 4 5}

What data supports the effectiveness of the High Fiber Diet treatment for obesity and colon cancer?

Research shows that diets high in dietary fiber, such as those including whole grains, fruits, and vegetables, are linked to a lower risk of colon cancer. Studies have found that switching from a high-fat diet to a high-fiber diet can reduce the incidence of colon cancer, suggesting that a high fiber diet may be beneficial for colon health. ^{1 2 3 4 5}

What safety data exists for high fiber diets in treating obesity and colon cancer?

The safety data for high fiber diets, often referred to by various names such as Healthy American Diet, Balanced Diet, or High Fiber Diet, suggest a protective effect against colorectal cancer. Studies indicate that diets rich in dietary fibers, vegetables, grains, and fruits are associated with a reduced risk of colorectal cancer. Meta-analyses of observational studies show a significant protective effect, with a combined odds ratio of 0.57 for high fiber intake. While some studies suggest that the protective effect may be due to fiber or other components in fiber-rich foods, the overall evidence supports the safety and potential benefits of high fiber diets in reducing the risk of colorectal cancer. ^{5 6 7 8 9}

Is a high fiber diet safe for humans?

Research suggests that a high fiber diet, which includes plenty of vegetables, grains, and fruits, is generally safe for humans and may even offer protective benefits against colorectal cancer. ^{5 6 7 8 9}

Is the High Fiber Diet a promising treatment for obesity and colon cancer?

Yes, a High Fiber Diet is promising for colon cancer because it may lower the risk of developing the disease. Studies suggest that eating more fiber, found in fruits, vegetables, and whole grains, can help protect against colon cancer. This diet is also linked to a lower risk of colorectal cancer and may reduce cancer rates overall. ^{1 4 5 9 10}

How does the High Fiber Diet treatment for obesity and colon cancer differ from other treatments?

The High Fiber Diet treatment is unique because it focuses on increasing fiber intake, which may help reduce the risk of colon cancer by counteracting the harmful effects of high-fat diets and red meat consumption. Unlike other treatments that might involve medication or surgery, this approach uses natural foods like legumes and fiber-rich foods to potentially protect against cancer and manage obesity. ^{1 4 5 9 10}

What is the purpose of this trial?

This study tests whether a high-fiber diet based on legumes, such as dry beans, can lead to sustained reductions in obesity and colon cancer risk in persons at highest risk, namely overweight or obese, post-polypectomy patients.

Research Team

Terry Hartman, PhD, MPH, RD

Principal Investigator

Emory University

Eligibility Criteria

This trial is for English-speaking adults aged 40-75 who are overweight or obese (BMI 25-40), can move around on their own, and have had a colonoscopy that found polyps in the last 3 years. It's not for those with serious health issues like cancer or heart disease, recent smokers, people with dietary restrictions, those changing exercise habits significantly soon, regular users of certain medications affecting gut function or inflammation markers, or women who are pregnant.

Inclusion Criteria

Colonoscopy within 3 years that found ≥1 adenoma >0.5 cm

I can walk, eat by myself, undergo tests, and understand consent forms.

BMI 25-40 kg/m2

Exclusion Criteria

Planning on substantially changing usual exercise behavior in the next 6 mos

Pregnant women, breast feeding women, or women planning pregnancy within the year of active study participation

I have a history of colorectal cancer, bowel surgery, multiple polyps, or chronic bowel inflammation.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Intensive Treatment

Participants receive two pre-portioned entrées per day featuring legumes during months 1 through 3

3 months

Monthly visits for monitoring and dietary guidance

Maintenance Treatment

Participants receive one pre-portioned entrée per day during months 4 through 6

3 months

Monthly visits for monitoring and dietary guidance

Self-directed Diet

Participants continue the high-fiber diet on their own during months 7 through 12

6 months

Visits at month 6 and month 12 for outcome measurements

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Healthy American Diet
• High Fiber Diet (HFD)

Trial Overview The study tests if a high-legume, high-fiber diet leads to more weight loss and lower intestinal cancer risk markers compared to a standard healthy American diet among individuals at risk for colorectal cancer due to obesity and previous polyps.

Participant Groups

Group I: High Fiber Diet Featuring Legumes (HLD) Experimental Treatment 1 Intervention

Participants randomized to the high fiber diet featuring legumes (HLD) will add approximately 30 grams of dietary fiber per day from legume dishes, ensuring a total intake of approximately 50 grams of dietary fiber per day.

Group II: Healthy American Diet Control Arm Active Control 1 Intervention

Participants randomized to the healthy American diet control arm will receive pre-portioned meal replacement entrées with legumes replaced by lean chicken or meat.

Who Is Running the Clinical Trial?

Emory University

Lead Sponsor

Trials

1,735

Recruited

2,605,000+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

Findings from Research

In a study involving 20 C57BL/6J Apc Min/+ mice over 60 days, high-fat diets without fiber were linked to a significantly higher incidence of small bowel tumors compared to diets with fiber, suggesting that fiber may offer protective effects against these tumors.

Despite variations in fiber content, the study found that high-fat diets increased tumor burden and colonic atypical hyperplasia, indicating that dietary fat may have a more pronounced effect on tumor development than fiber in this model, particularly for colon cancer.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Differential dietary effects on colonic and small bowel neoplasia in C57BL/6J Apc Min/+ mice. Yu, CF., Whiteley, L., Carryl, O., et al.[2019]

A diet high in dietary fiber, particularly from wheat bran, is associated with a reduced risk of colon cancer, as shown in various studies including case-control and animal models.

Wheat bran specifically inhibits colon tumor development more effectively than other fiber sources like oat and corn bran, and it reduces levels of tumor promoters in the colon, highlighting its potential as a protective dietary component.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Role of dietary fiber in colon cancer: an overview. Reddy, BS.[2019]

Epidemiological studies suggest that increasing dietary fiber intake and reducing dietary fat may help lower the risk of developing colon cancer in humans.

Among various dietary fibers, wheat bran has shown the most promise in inhibiting colon tumor development, although animal studies have produced mixed results due to methodological differences.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary fiber and colon cancer: animal model studies. Reddy, BS.[2019]

While some studies suggest a negative association between dietary fiber intake and colon cancer rates, the evidence remains inconsistent and inconclusive, with some studies even indicating a potential positive association in certain populations.

Despite the lack of definitive proof that fiber protects against colorectal cancer, dietary guidelines promoting increased consumption of fiber-rich foods like cereals, fruits, and vegetables are still recommended as they are unlikely to cause harm and may contribute to overall health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fiber intake in different populations and colon cancer risk. McKeown-Eyssen, GE.[2019]

Higher intake of dietary fibers, found in fruits and vegetables, is associated with a decreased risk of developing colorectal cancer, especially in populations that switch from a high red meat and fat diet to a fiber-rich diet.

Increased fiber consumption is also linked to lower mortality rates from colorectal cancer, highlighting the protective benefits of dietary fibers against this disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Protective effect of dietary fibers against colorectal carcinoma. Mia, MA., Siddiqui, MN., Rukunuzzaman, M., et al.[2017]

A review of 37 observational studies and meta-analyses of 16 case-control studies suggests that a high-fiber diet is associated with a reduced risk of colon cancer, with an estimated odds ratio of 0.57, indicating a significant protective effect.

While both fiber intake and vegetable consumption appear to lower colon cancer risk, the specific contributions of dietary fiber versus other beneficial components in vegetables remain unclear, as both factors are correlated.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary fiber, vegetables, and colon cancer: critical review and meta-analyses of the epidemiologic evidence. Trock, B., Lanza, E., Greenwald, P.[2022]

Higher fiber intake is associated with a reduced risk of colorectal cancer (CRC), as it promotes the production of butyrate, a compound with anti-cancer properties.

Conversely, a high-fat diet increases CRC risk by enhancing the conversion of bile acids into harmful compounds like deoxycholic acid, suggesting that managing fiber and fat intake could be effective strategies for CRC prevention.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fiber, Fat, and Colorectal Cancer: New Insight into Modifiable Dietary Risk Factors. Ocvirk, S., Wilson, AS., Appolonia, CN., et al.[2023]

In a study of 88,757 women over 16 years, no significant link was found between dietary fiber intake and the risk of developing colorectal cancer, with a relative risk of 0.95 for the highest fiber intake compared to the lowest.

The research also showed no protective effect of dietary fiber against colorectal adenomas, suggesting that increasing fiber consumption may not reduce the risk of these conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary fiber and the risk of colorectal cancer and adenoma in women. Fuchs, CS., Giovannucci, EL., Colditz, GA., et al.[2022]

In a study of 47,949 U.S. male health professionals, high intake of red meat was associated with a significantly increased risk of colon cancer, with a relative risk of 1.71 for those consuming the most compared to the least red meat.

Men who consumed beef, pork, or lamb five or more times a week had an even higher relative risk of 3.57 for developing colon cancer, indicating a strong link between red meat consumption and cancer risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intake of fat, meat, and fiber in relation to risk of colon cancer in men. Giovannucci, E., Rimm, EB., Stampfer, MJ., et al.[2019]

In a study using a dimethylhydrazine model for colon cancer, rats fed diets high in fat showed an increased incidence and number of tumors, highlighting the role of dietary fat in colon carcinogenesis.

Adding dietary fiber to high-fat diets provided significant protection against tumor development, with complete protection observed when saturated fat was combined with fiber, suggesting that fiber can counteract the harmful effects of fat on colon health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The fat/fiber antagonism in experimental colon carcinogenesis. Trudel, JL., Senterman, MK., Brown, RA.[2017]

References

1. United States pubmed.ncbi.nlm.nih.gov

Differential dietary effects on colonic and small bowel neoplasia in C57BL/6J Apc Min/+ mice. [2019]

2. United States pubmed.ncbi.nlm.nih.gov

Role of dietary fiber in colon cancer: an overview. [2019]

3. United States pubmed.ncbi.nlm.nih.gov

Dietary fiber and colon cancer: animal model studies. [2019]

4. United States pubmed.ncbi.nlm.nih.gov

Fiber intake in different populations and colon cancer risk. [2019]

5. Bangladesh pubmed.ncbi.nlm.nih.gov

Protective effect of dietary fibers against colorectal carcinoma. [2017]

6. United States pubmed.ncbi.nlm.nih.gov

Dietary fiber, vegetables, and colon cancer: critical review and meta-analyses of the epidemiologic evidence. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Fiber, Fat, and Colorectal Cancer: New Insight into Modifiable Dietary Risk Factors. [2023]

8. United States pubmed.ncbi.nlm.nih.gov

Dietary fiber and the risk of colorectal cancer and adenoma in women. [2022]

9. United States pubmed.ncbi.nlm.nih.gov

Intake of fat, meat, and fiber in relation to risk of colon cancer in men. [2019]

10. United States pubmed.ncbi.nlm.nih.gov

The fat/fiber antagonism in experimental colon carcinogenesis. [2017]