Supplementing a Low-Protein Diet with Dibasic Amino Acids Increases Urinary Calcium Excretion in Young Women. Issue 3 (15th January 2014)

• Record Type: Journal Article
• Authors: Bihuniak, Jessica D.; Sullivan, Rebecca R.; Simpson, Christine A.; Caseria, Donna M.; Huedo-Medina, Tania B.; O'Brien, Kimberly O.; Kerstetter, Jane E.; Insogna, Karl L.
• Is Part Of: Journal of nutrition. Volume 144:Issue 3(2014)
• Page Start: 282
• Page End: 288
• Publication Date: 2014-01-15
• Subjects: Nutrition -- Periodicals; Diet -- Periodicals; 613.205
• DOI: 10.3945/jn.113.185009
• Languages: English
• ISSNs: 0022-3166

Abstract

Abstract: Increasing dietary protein within a physiologic range stimulates intestinal calcium absorption, but it is not known if specific amino acids or dietary protein as a whole are responsible for this effect. Therefore, we selectively supplemented a low-protein (0.7 g/kg) diet with either the calcium-sensing receptor-activating amino acids (CaSR-AAAs) L-TRYPTOPHAN, L-PHENYLALANINE, and L-HISTIDINE, or the dibasic amino acids (DAAs) L-ARGININE and L-LYSINE, to achieve intakes comparable to the content of a high-protein diet (2.1 g/kg) and measured intestinal calcium absorption. Fourteen young women took part in a placebo-controlled, double-blind, crossover feeding trial in which each participant ingested a 6-d low-protein diet supplemented with CaSR-AAAs, DAAs, or methylcellulose capsules (control) after an 11-d adjustment period. All participants ingested all 3 diets in random order. Intestinal calcium absorption was measured between days 5 and 6 using dual-stable calcium isotopes ( 42 Ca, 43 Ca, and 44 Ca). There was no difference in calcium absorption between the diet supplemented with CaSR-AAAs (22.9 ± 2.0%) and the control diet (22.3 ± 1.4%) ( P = 0.64). However, calcium absorption tended to be greater during the DAA supplementation period (25.2 ± 1.4%) compared with the control diet period (22.3 ± 1.4%) ( P < 0.10). Larger and longer clinical trials are needed to clarify the possible benefit of arginine and lysine on calcium absorption.