%0 Journal Article
%T 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
%A Bess Dawson-Hughes
%A Donato A. Rivas
%A Lee M. Margolis
%A Lisa Ceglia
%A Roger A. Fielding
%J Archive of "Nutrients".
%D 2018
%R 10.3390/nu10050624
%X 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 ¡À 4 years) overweight (BMI: 28.5 ¡À 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 ¡À 27.8 mmol£¿day£¿1 in KHCO3 and 43.9 ¡À 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
%K weight loss
%K aging
%K alkaline supplement
%K acid-base
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986503/