Sabboh Houda, Horcajada Marie-Noëlle, Coxam Véronique, Tressol Jean-Claude, Besson Catherine, Rémésy Christian, Demigné Christian
Unité des Maladies Métaboliques et Micronutriments, INRA de Clermont-Ferrand/Theix and CRNH d'Auvergne, 63122 St-Genès-Champanelle, France.
Br J Nutr. 2005 Aug;94(2):192-7. doi: 10.1079/bjn20051474.
Low-grade metabolic acidosis, consecutive to excessive catabolism of sulfur amino acids and a high dietary Na:K ratio, is a common feature of Western food habits. This metabolic alteration may exert various adverse physiological effects, especially on bone, muscle and kidneys. To assess the actual effects of various K salts, a model of the Westernised diet has been developed in rats: slight protein excess (20 % casein); cations provided as non-alkalinising salts; high Na:K ratio. This diet resulted in acidic urine (pH 5.5) together with a high rate of divalent cation excretion in urine, especially Mg. Compared with controls, K supplementation as KCl accentuated Ca excretion, whereas potassium bicarbonate or malate reduced Mg and Ca excretion and alkalinised urine pH (up to 8). In parallel, citraturia was strongly increased, together with 2-ketoglutarate excretion, by potassium bicarbonate or malate in the diet. Basal sulfate excretion, in the range of 1 mmol/d, was slightly enhanced in rats fed the potassium malate diet. The present model of low-grade metabolic acidosis indicates that potassium malate may be as effective as KHCO3 to counteract urine acidification, to limit divalent cation excretion and to ensure high citrate concentration in urine.
低级别代谢性酸中毒是西方饮食习惯的一个常见特征，它继发于含硫氨基酸的过度分解代谢以及较高的饮食钠钾比。这种代谢改变可能会产生各种不良生理影响，尤其是对骨骼、肌肉和肾脏。为了评估各种钾盐的实际效果，在大鼠中建立了一种西式饮食模型：蛋白质略有过量（20%酪蛋白）；阳离子以非碱化盐的形式提供；钠钾比高。这种饮食导致尿液呈酸性（pH 5.5），同时尿中二价阳离子排泄率较高，尤其是镁。与对照组相比，补充氯化钾会加剧钙的排泄，而碳酸氢钾或苹果酸钾则会减少镁和钙的排泄，并使尿液pH值碱化（高达8）。同时，饮食中的碳酸氢钾或苹果酸钾会使枸橼酸尿症和2-酮戊二酸排泄量大幅增加。基础硫酸盐排泄量在1 mmol/d范围内，喂食苹果酸钾饮食的大鼠的基础硫酸盐排泄量略有增加。目前的低级别代谢性酸中毒模型表明，苹果酸钾在对抗尿液酸化、限制二价阳离子排泄以及确保尿液中高枸橼酸盐浓度方面可能与碳酸氢钾同样有效。
