Supplementing a Low-Protein Diet with Dibasic Amino Acids Increases Urinary Calcium Excretion in Young Women

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 lowprotein (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 6 2.0%) and the control diet (22.3 6 1.4%) (P = 0.64). However, calcium absorption tended to be greater during the DAA supplementation period (25.2 6 1.4%) compared with the control diet period (22.3 6 1.4%) (P < 0.10). Larger and longer clinical trials are needed to clarify the possible benefit of arginine and lysine on calcium absorption.

Soy protein improves tibial whole-bone and tissue-level biomechanical properties in ovariectomized and ovary-intact, low-fit female rats

“…Both GH and IGF-I are osteogenic with some of the effects of GH mediated via IGF-I ( Yakar et al, 2002 ; Locatelli and Bianchi, 2014 ; Ohlsson et al, 1998 ). In addition, the relatively high levels of arginine and lysine compared to animal-based proteins, might increase calcium absorption ( Bihuniak et al, 2014 ). Soy protein increases expression of intestinal calcium transporters, specifically TRPV6, in rats ( Gaffney-Stomberg et al, 2014 ).…”

The effects of dietary protein and amino acids on skeletal metabolism

“…As noted earlier, studies from Wasserman and colleagues reported an effect of lysine and arginine on calcium absorption in rats (Comar et al, 1956; Wasserman et al, 1957). We also recently demonstrated a trend toward higher calcium absorption in young women when a low-protein diet was supplemented with arginine and lysine (Bihuniak et al, 2014). The data from Torricelli et al (2002, 2003) underscore the importance of a comprehensive analysis of the effects of amino acids on bone cells both individually as well as in functionally relevant combinations.…”

“…The authors hypothesized that L-lysine and vitamin D may be acting via different cellular pathways to increase intestinal calcium absorption. We recently undertook a crossover feeding study in 14 young Asian and Caucasian women and assessed the effect of amino acid supplementation on intestinal calcium absorption (Bihuniak et al, 2014). Each participant ingested a low-protein diet (0.7 g protein/kg) supplemented with: (1) L-tryptophan, L-phenylalanine, and L-histidine, (2) L-arginine and L-lysine, and (3) methylcellulose capsules (control) and calcium absorption was assessed after 6 days using dual stable calcium isotopes.…”

Calcium Oxalate Nephrolithiasis and Gut Microbiota: Not just a Gut-Kidney Axis. A Nutritional Perspective

“…Animal proteins raise the renal acid load, which is associated with reduced excretion of lithogenesis inhibitors such as citrate [72,73] and incident kidney stones in population-based studies [74]. Amino acid and protein supplementation are also associated with increased urinary calcium excretion [75,76], while mild protein intake restriction reduces calcium excretion [77]. Thus, limiting animal protein intake is one of the cornerstone measures for preventing calcium lithiasis recurrence [16,17,62].…”