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标题：Pilot Study Examining the Influence of Potassium Bicarbonate Supplementation on Nitrogen Balance and Whole-Body Ammonia and Urea Turnover Following Short-Term Energy Restriction in Older Men
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作者：Lee M. Margolis ; Lisa Ceglia ; Donato A. Rivas 等
期刊名称：Nutrients
电子版ISSN：2072-6643
出版年度：2018
卷号：10
期号：5
页码：624
DOI：10.3390/nu10050624
语种：English
出版社：MDPI Publishing
摘要：With aging there is a chronic low-grade metabolic-acidosis that may exacerbate negative protein balance during weight loss. The objective of this randomized pilot study was to assess the impact of 90 mmol∙day−1 potassium bicarbonate (KHCO3) versus a placebo (PLA) on 24-h urinary net acid excretion (NAE), nitrogen balance (NBAL), and whole-body ammonia and urea turnover following short-term diet-induced weight loss. Sixteen (KHCO3; n = 8, PLA; n = 8) older (64 ± 4 years) overweight (BMI: 28.5 ± 2.1 kg∙day−1) men completed a 35-day controlled feeding study, with a 7-day weight-maintenance phase followed by a 28-day 30% energy-restriction phase. KHCO3 or PLA supplementation began during energy restriction. NAE, NBAL, and whole-body ammonia and urea turnover (15N-glycine) were measured at the end of the weight-maintenance and energy-restriction phases. Following energy restriction, NAE was −9.8 ± 27.8 mmol∙day−1 in KHCO3 and 43.9 ± 27.8 mmol∙day−1 in PLA (p < 0.05). No significant group or time differences were observed in NBAL or ammonia and urea turnover. Ammonia synthesis and breakdown tended (p = 0.09) to be higher in KHCO3 vs. PLA following energy restriction, and NAE was inversely associated (r = −0.522; p < 0.05) with urea synthesis in all subjects. This pilot study suggests some benefit may exist with KHCO3 supplementation following energy restriction as lower NAE indicated higher urea synthesis.
关键词：weight loss; aging; alkaline supplement; acid-base weight loss ; aging ; alkaline supplement ; acid-base