Steven B. Machek1,2, Emilia E. Zawieja3, Jeffery L. Heileson1, Dillon R. Harris1, Dylan T. Wilburn1, Emma A. Fletcher1, Jason M. Cholewa4, Artur Szwengiel3, Agata Chmurzynska3 & Darryn S. Willoughby, FASCM1,5

1Baylor University, Waco, TX; 2University of the Ozarks, Clarksville, AR; 3The Poznań University of Life Sciences, Poznań, Poland; 4University of Lynchburg, Lynchburg, VA; 5University of Mary Hardin-Baylor, Belton, TX

Several previous investigations have employed betaine supplementation in randomized controlled crossover designs to assess its ostensible ergogenic potential. Nevertheless, prior methodology is predicated on limited pharmacokinetic data and an appropriate betaine-specific washout period is hitherto undescribed. PURPOSE: To determine whether a 28-day washout period was sufficient to return serum betaine concentrations and several associated parameters to baseline following a supplementation protocol. METHODS: In the present pilot study, five resistance trained men (26±6y) supplemented with 6g/day betaine anhydrous for 14-days and subsequently visited the lab 10 additional times amidst a 28-day washout period. Participants underwent venipuncture to assess serum betaine and several other parameters before (PRE) and periodically throughout the washout timeframe (POST-0, -4, -7, -10, -13, -16, -19, -22, -25, and -28 [days]). Serum betaine was quantified employing liquid chromatography-mass spectrometry, whereas several other associated serum variables were assessed using hematocrit and ELISA. All aforementioned variables were analyzed via separate one-way repeated measures ANOVA at a significance level of p<.05 and significant results assessed using Bonferroni-adjusted pairwise comparisons. RESULTS: While analyses failed to detect any differences in any associated serum parameter, serum betaine demonstrated a significant main time effect (p=.010; ηp2=.820). However, no significant pairwise comparisons were observed due to Bonferroni α adjustments, and thus a follow-up analysis was performed to further determine the supplementation time point at which concentrations were no longer statistically significant versus PRE. A significant time effect was once again observed (p=.007; ηp2=.842), whereby serum betaine was significantly elevated from PRE-to-POST0 (p=.047; 2.31±1.05 to 11.1±4.91µg•mL-1) and was statistically indistinguishable from baseline at POST4 (p=1.00). CONCLUSION: Despite the current findings, visual data assessment and an inability to assess skeletal muscle concentrations would otherwise suggest that a more conservative 7-day washout period is sufficient to truly return both serum-and-skeletal muscle betaine content to pre-supplementation levels.

ACKNOWLEDGEMENTS: The present research was partially funded by the Baylor University Health, Human Performance, and Recreation Doctoral Dissertation Research Grant and the Polish National Science Centre under Grant DEC2017/27/N/NZ9/00750 (approximately 40% and 60% of total funding, respectively).

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