(P01-17-26) The Effects of Red Meat on Gut-Derived Uremic Toxins in Adults With Chronic Kidney Disease: Protocol for a Crossover-Controlled Feeding Feasibility Study

Objectives: Cardiovascular disease is the leading cause of morbidity and mortality in people with chronic kidney disease (CKD). Many uremic toxins, substances that build up with CKD and cause detrimental health effects, are gut-derived from amino acid precursors. This feasibility study aims to determine the effects of red meat intake on gut-derived uremic toxins in people with CKD.

Methods: A randomized, crossover, controlled feeding trial will be conducted in 12 adults aged 40-70 years with moderate CKD (eGFR 30 to 59 mL/min/1.73 m²). Participants will complete two three-week periods separated by a five-week washout period. During the intervention periods, participants will consume 0.8g of protein/kg body weight from a lacto-ovo vegetarian (LOV) diet or the same diet modified by the isonitrogenous replacement of 20% total protein with unprocessed red meat (LOVM) and validated by chemical analysis of the menu. During each study period (before start, both study diets, and washout), outcomes will be measured twice, including the fecal microbiota, uremic toxins (including trimethylamine N-oxide, p-cresyl sulfate, and indoxyl sulfate), and cardiovascular risk factors (fasting blood lipids and blood pressure).

Results: Nutrient database-estimated (80.3 LOV and 80.5g LOVM) and chemically analyzed (80.8 LOV and 81.6g LOVM) protein values, as well as other key nutrients (macronutrients, sodium, potassium, phosphorus), were within 10%. Inter- and intra-person variabilities will be compared, and linear mixed-effects models will be used to analyze trial data. We hypothesize that these results will demonstrate smaller intra-person variability, supporting the use of a crossover design, and providing data needed for a power analysis to inform a larger trial.

Conclusions: This study will provide information on the effects of a nutrient-validated lacto-ovo vegetarian diet with or without red meat on gut-derived uremic toxins and inform the design of future studies examining the effects of high-protein foods on cardiometabolic outcomes in people with non-dialysis CKD.

Funding Sources: Indiana CTSI K12TR004415, Showalter Research Trust, Indiana CTSI UM1TR004402.