Influence of 2-Weeks DuraBeet® Ingestion on Cycling Performance, Gut Permeability, and Metabolite Shifts

This study will employ a randomized crossover design. Study participants will be randomized to two trials using double-blinded, placebo-controlled procedures. The supplement capsules (betaine and placebo) will be coded by the sponsor, with the double-blind code held until after all study samples have been analyzed. Subjects will come to the lab for orientation/baseline testing, pre-and post-supplementation blood sample collections (2 weeks supplementation with betaine or placebo), two 60-km cycling sessions, and two 24-h recovery lab sessions (thus 8 total lab visits). Subjects will complete a COVID-19 screening questionnaire before entering the lab (all visits). The total amount of time subjects will be asked to volunteer for this study is about 18 hours at the Human Performance Laboratory (over a 6-week period).

A. Orientation (Visit #1). Subjects will report to the lab in an overnight fasted state. Subjects will voluntarily sign IRB-approved consent forms and complete questionnaires (delayed onset of muscle soreness or DOMS, Profile of Mood States or POMS). Demographic, health, and training histories will be acquired with questionnaires. A blood sample will be collected. Body composition and total body water will be measured using 8-point bioelectrical impedance (BIA). Subjects will ingest a standardized sugar solution containing lactulose 5 g, 13C mannitol 100 mg, mannitol 1.9 g, and rhamnose 1 g in a total of 450 ml water (SS, calculated osmolality 69 mosmol/kg). An increase in the post-exercise lactulose/13C mannitol ratio (L/M) will be used as an indicator of increased gut permeability. All urine excreted for five hours post SS ingestion will be collected in a urine collection container. Subjects will be urged to drink water after the first hour of the test to ensure adequate urine output. The Boost beverage will be consumed at 7 kcal/kg 1.5 h post SS ingestion (to simulate what occurs post-exercise). The urine collection container will be placed in the refrigerator until they are returned to the lab the next day. The total urine volume will be measured with four 10 ml aliquots frozen in a minus 80°C freezer until analysis.

B. Baseline Testing/Pre-Supplementation (Visit #2). Subject will return the urine collection container to the lab the day after Visit #1. Body composition will be measured with the Bod Pod body composition analyzer (Life Measurement, Concord, CA). Study participants will be tested for maximal aerobic capacity (VO2max) during a graded, cycling test with continuous metabolic monitoring with the Cosmed CPET metabolic device (Cosmed, Rome, Italy). A 2-week supply of betaine or placebo capsules will be given to the participants. Subjects will consume 6 capsules per day, 3 with the first meal in the morning and 3 more with the last meal of the day.

DuraBeet Betaine supplement. DuraBeet® crystalline betaine is produced from beet molasses at the betaine crystallization plant, in Austria, according to strict European standards. The white crystalline betaine will be in 6 capsules (3 g/day). The placebo capsules will contain a white cellulose powder in identical looking capsules.

C. 60-km Cycling Session (Lab Visit #3): During the 3-day period prior to the 60-km cycling session, subjects will taper exercise training and ingest a moderate-carbohydrate diet using a food list restricting high fat foods, visible fats, and caffeine. Subjects will record all food and beverage intake in a 3-day food record with macro- and micro-nutrient intake calculated using the ESHA Food Processor nutrient analysis software program. Study participants will report to the Human Performance Lab in an overnight fasted state and provide a blood sample, ingest the supplement (3 capsules of betaine or placebo), and then cycle 60-km at the fastest pace possible while ingesting water alone (3 ml/kg every 15 minutes). Immediately following the cycling bout, subjects will ingest the gut permeability sugar solution (SS). Blood samples will be collected at 0 h, 1.5 h, 3.0 h, and 24-h post-exercise. All urine excreted for five hours after SS ingestion will be collected in a urine collection container.