The Effect of Dietary Protein on Intestinal Calcium Absorption in Rats

Gaffney‐Stomberg, Erin; Sun, Ben‐hua; Cucchi, C; Simpson, Christine; Gundberg, Caren M.; Kerstetter, Jane E.; Insogna, Karl L.

doi:10.1210/en.2009-0744

Cited by 27 publications

(14 citation statements)

References 29 publications

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“…Consuming supplemental protein may optimize the whole-body and skeletal muscle metabolic responses to periods of intense physical training and preserve lean body mass by sustaining muscle protein balance, attenuating proteolysis, and promoting muscle protein accretion (4,7,8). Consuming a high-protein diet (supplemental or dietary) may also enhance bone health by attenuating bone turnover and increasing intestinal calcium absorption, if calcium intake is adequate (14)(15)(16). During repeated days and weeks of intense physical training and periods of training overload, supplemental protein may also mitigate the risk of injury and overtraining, although direct evidence for this is currently lacking (17).…”

Section: Dietary Protein Recommendations For Warfighters: Efficacy Ofmentioning

confidence: 99%

Efficacy and Safety of Protein Supplements for U.S. Armed Forces Personnel: Consensus Statement

Pasiakos

Austin

Lieberman

et al. 2013

The Journal of Nutrition

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To provide evidence-based guidance regarding the efficacy and safety of dietary protein supplement (PS) use by members of the U.S. Armed Forces, a panel of internationally recognized experts in the fields of protein metabolism and dietary supplement research was convened by the Department of Defense Center Alliance for Dietary Supplement Research and the U.S. Army Medical Research and Material Command. To develop a consensus statement, potential benefits, risks, and strategies to optimize military performance through PS use were considered in the context of specific warfighter populations and occupational demands. To maintain muscle mass, strength, and performance during periods of substantial metabolic demand and concomitant negative energy balance the panel recommended that warfighters consume 1.5-2.0 g · kg(-1) · d(-1) of protein. However, if metabolic demand is low, such as in garrison, protein intake should equal the current Military Dietary Reference Intake (0.8-1.5 g · kg(-1) · d(-1)). Although PS use generally appears to be safe for healthy adults, warfighters should be educated on PS quality, given quality-control and contamination concerns with commercial dietary supplements. To achieve recommended protein intakes, the panel strongly urges consumption of high-quality protein-containing whole foods. However, when impractical, the use of PSs (20-25 g per serving or 0.25-0.3 g · kg(-1) per meal), particularly after periods of strenuous physical activity (e.g., military training, combat patrols, and exercise), is acceptable. The committee acknowledges the need for further study of protein requirements for extreme, military-specific environmental conditions and whether unique metabolic stressors associated with military service alter protein requirements for aging warfighters.

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Section: Dietary Protein Recommendations For Warfighters: Efficacy Ofmentioning

confidence: 99%

Efficacy and Safety of Protein Supplements for U.S. Armed Forces Personnel: Consensus Statement

Pasiakos

Austin

Lieberman

et al. 2013

The Journal of Nutrition

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“…Comparable observations were made in later rat studies, 11,12 and Whiting and Draper 12 confirmed no benefit or harm to bone mass or composition after 10 months of a diet providing 35% energy as protein (soy and lactalbumin). A recent study by Gaffney-Stomberg et al 13 studied vesicles developed from the intestinal brush border mucosa of rats fed 5, 20, and 40% energy as protein, observing an increased Vmax, but no change in Km of calcium uptake. These changes explained a 14.4% improvement in calcium absorption in high-versus low-protein animals, which more than compensated for protein-induced urine losses.…”

Section: Clinical Effect Of Protein On Calcium Absorptionmentioning

confidence: 99%

“…[4][5][6] Indeed, urinary calcium losses are unequivocally induced by high protein intakes. 7 In contrast, equally diverse research paradigms support that dietary protein increases calcium absorption or bioavailability, [8][9][10][11][12][13] casting the net effect of high-protein diets on the calcium economy into doubt. Furthermore, trials have persuasively demonstrated that increased protein intake may initiate bone anabolism mediated by the protein-sensitive insulin-like growth factor 1 (IGF-1).…”

Section: Introductionmentioning

confidence: 99%

Dietary protein and bone health: harmonizing conflicting theories

Thorpe

Evans

2011

Nutrition Reviews

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No clear consensus on the role of higher protein intakes has emerged, in spite of many decades of research. Protein unambiguously increases urinary calcium losses, which is completely attributable to the dietary acid load imposed by metabolism of sulfur containing amino acids into acid equivalents. Although alternate dietary sources of fixed acid cause demineralization of bone and apparent osteoporosis, this effect has not been consistently observed for protein, suggesting opposing, beneficial effects on bone. Specifically, protein may improve bone health through improving calcium absorption, increasing total circulating insulin-like growth factor 1 or by improving lean body mass which in turn increases bone growth. Although the notion of competing positive and negative pathways has been articulated theoretically, statistical mediation models of this "dual pathways" relationship have not been employed to quantify these relationships.In a cross-sectional investigation of postmenopausal women, protein intake is positively related to bone mineral density of the lumbar spine following adjustment for an accompanying negative effect mediated by the sulfur containing fraction of protein. In growing rats, an analogous and complementary pattern emerged: A negative association of protein intake with bone strength was suppressed by an opposing, positive effect of protein mediated by insulin-like growth factor 1. A second animal study assessed the influence of protein source on bone strength and bone mineral content of growing rats consuming isoenergetic, isonitrogenous diets. The influence of protein source was completely mediated by the corresponding changes in lean body mass.ii iii A randomized, controlled trial indicated a higher protein diet preserved bone density during weight loss compared to a conventional, MyPyramid based diet; however the protein diet also contained more calcium. A mathematical model of calcium availability in this trial suggested that this additional dietary calcium was not sufficient to explain differences in calcium accrual between groups unless calcium availability was also improved in the higher protein diet. Also, within this study, urine calcium (a surrogate of the diet acid load) exhibited a negative association with bone density change, in spite of its positive association with protein intake.The striking consistency of a dual pathway model across populations and experimental models lends credence to the notion that dietary protein may hold a positive or negative effect on bone health, depending on other factors in the diet. Specifically, we find support that the sulfur containing amino acid induced dietary acid load holds negative effects that may be opposed by positive influences of insulin-like growth factor 1, calcium availability or lean body mass. On average, this effect is probably null or too small to be of clinical importance.The effect may be of public health relevance, however, if the diet can be manipulated in order to uncouple positive and negative pathways. If correc...

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“…As monogastric species do not have the similar potential to utilise N efficiently, a low-protein diet changes metabolic pathways seriously. A reduction of dietary protein leads to changes in Ca and inorganic phosphate (P i ) homoeostasis in monogastric animals and humans, including decrease in intestinal Ca absorption, reduced urinary Ca excretion and diminished plasma calcitriol and insulin-like growth factor 1 (IGF1) concentrations (5)(6)(7)(8) .…”

mentioning

confidence: 99%

Modulation of intestinal calcium and phosphate transport in young goats fed a nitrogen- and/or calcium-reduced diet

Elfers¹,

Wilkens²,

Breves³

et al. 2015

Br J Nutr

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Feeding ruminants a reduced N diet is a common approach to reduce N output based on rumino-hepatic circulation. However, a reduction in N intake caused massive changes in Ca and inorganic phosphate (P i ) homoeostasis in goats. Although a single dietary Ca reduction stimulated intestinal Ca absorption in a calcitriol-dependent manner, a concomitant reduction of Ca and N supply led to a decrease in calcitriol, and therefore a modulation of intestinal Ca and P i absorption. The aim of this study was to examine the potential effects of dietary N or Ca reduction separately on intestinal Ca and P i transport in young goats. Animals were allocated to a control, N-reduced, Ca-reduced or combined N-and Ca-reduced diet for about 6 − 8 weeks, whereby N content was reduced by 25 % compared with recommendations. In Ussing chamber experiments, intestinal Ca flux rates significantly decreased in goats fed a reduced N diet, whereas P i flux rates were unaffected. In contrast, a dietary Ca reduction stimulated Ca flux rates and decreased P i flux rates. The combined dietary N and Ca reduction withdrew the stimulating effect of dietary Ca reduction on Ca flux rates. The expression of Ca-transporting proteins decreased with a reduced N diet too, whereas P i -transporting proteins were unaffected. In conclusion, a dietary N reduction decreased intestinal Ca transport by diminishing Ca-transporting proteins, which became clear during simultaneous N and Ca reduction. Therefore, N supply in young ruminant nutrition is of special concern for intestinal Ca transport.Key words: Flux rates of calcium and phosphate: Goats: Na + -dependent P i transporter IIb: Transient receptor potential vanilloid channel type 6: Ussing chambersFeeding ruminants a N-reduced diet is preferable for economic and environmental reasons. Dietary crude protein (CP) concentrations of 11 − 12 % were recommended to meet the requirements of growing goats (1) . A reduced dietary N supply was associated with a significant reduction in urinary N excretion (2) due to increased expression of renal urea transporters, and thus greater renal urea re-absorption (3) in goats. In addition, the urea transporting capacity of the ruminal epithelium was increased due to dietary N reduction (4) . By possessing such efficient recycling mechanisms, ruminants such as goats are able to maintain rumen microbes' N supply, and therefore a sufficient synthesis of microbial protein as the most important source for host protein, provided that energy supply to the rumen flora is also adequate for microbial protein synthesis.As monogastric species do not have the similar potential to utilise N efficiently, a low-protein diet changes metabolic pathways seriously. A reduction of dietary protein leads to changes in Ca and inorganic phosphate (P i ) homoeostasis in monogastric animals and humans, including decrease in intestinal Ca absorption, reduced urinary Ca excretion and diminished plasma calcitriol and insulin-like growth factor 1 (IGF1) concentrations (5)(6)(7)(8) .Despite the N-rec...

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The Effect of Dietary Protein on Intestinal Calcium Absorption in Rats

Cited by 27 publications

References 29 publications

Efficacy and Safety of Protein Supplements for U.S. Armed Forces Personnel: Consensus Statement

Efficacy and Safety of Protein Supplements for U.S. Armed Forces Personnel: Consensus Statement

Dietary protein and bone health: harmonizing conflicting theories

Modulation of intestinal calcium and phosphate transport in young goats fed a nitrogen- and/or calcium-reduced diet

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