Effects of SCFA supplements on GI toxicity in cancer patients receiving radiation therapy

Inclusion Criteria:

* Written informed consent obtained to participate in the study and HIPAA authorization for release of personal health information. Consent for the use of any residual material from biopsy and/or surgical resection (archival tissue) and serial blood draws will be required for enrollment.
* ≥ 18 years of age on day of signing informed consent.
* ECOG performance score ≤ 2
* Subjects with histological or cytological evidence/confirmation of GI, urologic or gynecologic malignancy (including sarcoma) that will be treated with minimum dose of 40Gy (equivalent dose in 2Gy per fraction or EQD2) via 3D conformal fields or IMRT to abdomen or pelvis (multimodality treatment with surgery, systemic anti cancer therapy is permissible)
* Subjects may have had prior chemotherapy or surgery.
* Subjects deemed healthy for study inclusion by the treating physician based on the laboratory values at screening and general health status.
* Prior cancer treatment must be completed at least 14 days prior to registration and the subject must have recovered from all reversible acute toxic effects of the regimen (other than alopecia) to ≤ Grade 1 or baseline.
* Females of childbearing potential must have a negative urine pregnancy test within 14 days prior to simulation. NOTE: Females are considered of childbearing potential unless they are surgically sterile (have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or they are naturally postmenopausal for at least 12 consecutive months. Documentation of postmenopausal status must be provided.
* Females of childbearing potential must be willing to abstain from heterosexual activity or to use 2 forms of effective methods of contraception from the time of informed consent until 14 or 28 days after treatment discontinuation. The two contraception methods can be comprised of two barrier methods, or a barrier method plus a hormonal method or an intrauterine device that meets \< 1% failure rate for protection from pregnancy in the product label.
* Male subjects with female partners of childbearing potential must have had a prior vasectomy or agree to use an adequate method of contraception (i.e., double barrier method: condom plus spermicidal agent) starting with the first dose of study therapy through 14-28 days after the last dose of study therapy.
* Subjects is willing and able to comply with study procedures based on the judgement of the investigator or protocol designee.

Exclusion Criteria:

* Pregnant or breastfeeding (NOTE: breast milk cannot be stored for future use while the mother is being treated on study).
* Prior abdominopelvic RT to a region with anticipated direct overlap with the present planned course of RT.
* History of inflammatory bowel disease or GI motility disorder
* Grade 2 or higher diarrhea at baseline unless deemed by the investigator to be caused by laxatives prescribed for symptomatic partial obstruction
* Concurrent use of histone deacetylase inhibitors (vorinostat)
* Baseline hypernatremia defined as serum sodium concentration \>145 mEg/L
* Creatinine clearance \< 50 mL/min
* Congestive heart failure
* On a salt restricted diet for medical indications
* Severe nut allergy
* Active central nervous system (CNS) metastases
* Subject must have completed treatment with any investigational drug other than the drugs in this study and subjects may not be on another clinical trial by no less than 14 days prior to registration. Subjects participating in interventional trials that does not include an investigational agent or any other drug are allowed at the discretion of the principal investigator.
* Subject is receiving prohibited medications or treatments as listed in section 5.6 of the protocol that cannot be discontinued/replaced by an alternative therapy.