Advantage of carbonate-versus citrate-based alkalinization on bone metabolism in moderately exercising aged male rats fed an acidogenic diet.

ABSTRACT

This study aims to determine the effects of different alkaline supplementations on high protein diet-induced abnormalities affecting bone metabolism in rats which were also undergoing physical exercise of moderate intensity. Sixty elderly Sprague-Dawley rats were randomly divided into four groups of 10 rats each and treated for 16 weeks as follows baseline control group fed normal food (C); acidic high-protein diet supplemented group (chronic acidosis, CA group), bicarbonate-based alkaline formula (Basenpulver, Named, Italy) supplemented chronic acidosis (BB-CA) and citrate-based alkaline supplement (CB-CA). Throughout the supplementation period, rats were put on a treadmill training mimicking a moderate level of exercise. In the CA group, 24-hour urinary calcium (Ca) and phosphorus (P) excretion were increased over 30 percent (p<0.05 vs normal diet controls). However serum Ca was not significantly changed. Femural and tibial BMD and BMC was significantly decreased in the CA group (p<0.05) but both alkaline supplementations prevented such phenomenon (p<0.05 vs CA), without significant difference between the two formulations although the BB-CA group showed significantly more preserved trabecular bone volume (p<0.05 vs CB-CA group). An increased level of over 50 percent of urinary Dpd observed in the CA group (p<0.001) was reverted to normal by both supplementations (p<0.001 vs CA group). The same applied to urinary net acid excretion (p<001) with BB-supplementation performing better than CB-supplementation (p<0.05). Moreover, while the latter did not modify Nterminal telopeptide value, BB-supplementation significantly normalized this parameter (p<0.05 vs CA group) which exercise and acidic protein diet had modified (p<0.01 vs control diet). Overall, the present study shows that a bicarbonate-based alkaline formula, when administered to a dose amenable to clinical use, may significantly protect bone structure in exercising aged animals to a greater extent than a quali/quantitavely similar citrate-based formula.