Effects of coffee on gut microbiome and liver health in colorectal cancer patients

Inclusion Criteria:

Participants must meet the following criteria on screening examination to be eligible to participate in the study:

* Participants must have histologically confirmed stage I, II, or III colon or rectal adenocarcinoma and have completed standard treatment (including surgery, chemotherapy and radiotherapy) at least 2 months ago.
* Age 18 years or older.
* This study will only include adult participants because colorectal carcinogenesis in children is more likely to be related to a cancer predisposition syndrome with distinct biological mechanisms compared with sporadic colorectal cancer in adults.
* The effects of coffee on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
* Subjects must be able and willing to follow study procedures and instructions.
* Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

Participants who exhibit any of the following conditions at screening will not be eligible for admission into the study.

* Participants who are receiving any other investigational agents.
* Concurrent use of other anti-cancer therapy, including chemotherapy agents, targeted agents, biological agents, immunotherapy, or investigational agents not otherwise specified in this protocol.
* Regularly consuming more than 2 cups of coffee ( 8 oz) per day for at least 3 days a week in the past month.
* Current or recent use (within 1 month) of any coffee supplements (e.g., green coffee extracts).
* History of diagnosed conditions that may be worsen by coffee, including arrhythmias, insomnia, tremors, tics, generalized anxiety disorder, bipolar disease, panic attacks, Tourette's, epilepsy or overactive bladder.
* History of adverse reactions to coffee or intolerance of coffee consumption.
* Inability or unwillingness to swallow capsules.
* History of malabsorption or uncontrolled vomiting or diarrhea, or any other disease that could interfere with absorption of oral medications.
* Any uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, or psychiatric illness/social situations that, in the opinion of the investigator, may increase the risks associated with study participation or study treatment, limit compliance with study requirements, or interfere with the interpretation of study results.
* Pregnant or breastfeeding. The effects of coffee on the developing human fetus are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation.

Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. Similarly, lactating women are excluded from this study because there is an unknown but potential risk of adverse events in nursing infants secondary to treatment of the mother with coffee. Consequently, breastfeeding should be discontinued if the mother is enrolled on the study.

* Presence of synchronous (at the same time) malignancy for which the patient is currently receiving active treatment.
* Known positive test for human immunodeficiency virus (HIV), hepatitis C virus, or acute or chronic hepatitis B infection.