Exploring the Effects of a High Chlorophyll Dietary Intervention to Reduce Colon Cancer Risk in Adults

Colon cancer is the third most common cancer in men and women and over 70% of cases are preventable. A western diet, characterized by low vegetable and high red and processed meat intake, indisputably increases colon cancer risk. Heme, which gives red meat its color, is highly reactive, induces hyperproliferation and promotes DNA damage in the colon to a greater degree than any other red meat-associated carcinogen. Preclinical models indicate dietary chlorophyll, which gives green leafy vegetables their color, binds and stabilizes heme in the lumen, preventing genotoxicity. Additionally, data from our randomized controlled weight loss trial indicate increasing red meat consumption has deleterious effects on the gut microbiome, which is also implicated in colon cancer etiology. Because heme-containing foods are the richest sources of bioavailable iron and several other vitamins and minerals, mitigating their potential risks may be more beneficial than eliminating meat, poultry, fish and seafood in their entirety from the diet for risk reduction. This feasibility study will begin to explore the research question: Will adding chlorophyll-rich green leafy vegetables to the diet prevent the deleterious effects of heme-rich red meat on the human host and microbiome? The investigators will randomly assign 50 adults at increased risk of colorectal adenoma to a block randomized crossover study with two 4-week dietary regimens in which: 1) participants will be provided with frozen green leafy vegetables and counseled to consume a high chlorophyll diet including 1 cup per day of cooked green leafy vegetables and normal meat (high heme) consumption; or 2) continue their normal high heme, low chlorophyll diet (control). A 4-week washout period encouraging habitual diet will be employed between the intervention periods and data will be collected at all four time points. This study is critical in translating preclinical findings and has the potential to open the door to new knowledge and standards of care in colon cancer prevention. This study is a required step to aid in the design of a larger RCT to determine whether increased green leafy vegetable consumption mitigates the negative effects of red meat on DNA damage, inflammatory cytokines and gut microbe composition. This could lead to equally beneficial dietary guidance for colon health that might be more easily attained by the general public through addition, rather than omission of specific foods.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Consume less than 2 servings of green leafy vegetables per day
* Consume 5 or more servings of red meat per week
* BMI \>30 kg/m2
* Agrees to not change dietary supplements during course of study
* Willing to comply with dietary regimen over course of study
* Able to store and cook frozen green leafy vegetables (freezer and microwave)
* Able to speak and read English

Exclusion Criteria:

* Previous diagnosis of colon cancer
* Use of any of the following in the past 4 weeks: systemic antibiotics, corticosteroids, immunosuppressive agents, commercial probiotics

• BACKGROUNDFruge AD, Ptacek T, Tsuruta Y, Morrow CD, Azrad M, Desmond RA, Hunter GR, Rais-Bahrami S, Demark-Wahnefried W. Dietary Changes Impact the Gut Microbe Composition in Overweight and Obese Men with Prostate Cancer Undergoing Radical Prostatectomy. J Acad Nutr Diet. 2018 Apr;118(4):714-723.e1. doi: 10.1016/j.jand.2016.10.017. Epub 2016 Dec 15. PMID 27988219
• BACKGROUNDFruge AD, Van der Pol W, Rogers LQ, Morrow CD, Tsuruta Y, Demark-Wahnefried W. Fecal Akkermansia muciniphila Is Associated with Body Composition and Microbiota Diversity in Overweight and Obese Women with Breast Cancer Participating in a Presurgical Weight Loss Trial. J Acad Nutr Diet. 2020 Apr;120(4):650-659. doi: 10.1016/j.jand.2018.08.164. Epub 2018 Nov 9. PMID 30420171
• RESULTFruge AD, Smith KS, Riviere AJ, Demark-Wahnefried W, Arthur AE, Murrah WM, Morrow CD, Arnold RD, Braxton-Lloyd K. Primary Outcomes of a Randomized Controlled Crossover Trial to Explore the Effects of a High Chlorophyll Dietary Intervention to Reduce Colon Cancer Risk in Adults: The Meat and Three Greens (M3G) Feasibility Trial. Nutrients. 2019 Oct 2;11(10):2349. doi: 10.3390/nu11102349. PMID 31581743
• DERIVEDRiviere AJ, Smith KS, Schaberg MN, Greene MW, Fruge AD. Plasma and fecal zonulin are not altered by a high green leafy vegetable dietary intervention: secondary analysis of a randomized control crossover trial. BMC Gastroenterol. 2022 Apr 12;22(1):184. doi: 10.1186/s12876-022-02248-3. PMID 35413837