Mixed compared with single-source proteins in high-protein diets affect kidney structure and function differentially in obesefa/faZucker rats

Abstract

Questions remain regarding the potential negative effects of dietary high protein (HP) on kidney health, particularly in the context of obesity in which the risk for renal disease is already increased. To examine whether some of the variability in HP effects on kidney health may be due to source of protein, obese fa/fa Zucker rats were given HP (35% of energy from protein) diets containing either casein, soy protein, or a mixed source of animal and plant proteins for 12 weeks. Control lean and obese rats were given diets containing casein at normal protein (15% of energy from protein) levels. Body weight and blood pressure were measured, and markers of renal structural changes, damage, and function were assessed. Obesity alone resulted in mild renal changes, as evidenced by higher kidney weights, proteinuria, and glomerular volumes. In obese rats, increasing the protein level using the single, but not mixed, protein sources resulted in higher renal fibrosis compared with the lean rats. The mixed-protein HP group also had lower levels of serum monocyte chemoattractant protein-1, even though this diet further increased kidney and glomerular size. Soy and mixed-protein HP diets also resulted in a small number of damaged glomeruli, while soy compared with mixed-protein HP diet delayed the increase in blood pressure over time. Since obesity itself confers added risk of renal disease, an HP diet from mixed-protein sources that enables weight loss but has fewer risks to renal health may be advantageous.

Long Term High Protein Diet Feeding Alters the Microbiome and Increases Intestinal Permeability, Systemic Inflammation and Kidney Injury in Mice

“…High protein diets have been shown to worsen albuminuria in otherwise healthy rats [ 26,27 ] and mice. [ 28–31 ] The current study observed an increase in renal hypertrophy, consistent with some, [ 26,27,32,33 ] but not all [ 34 ] previous animal studies. In this study we observed an upregulation of NFĸB p65 mRNA in the kidney cortex with high protein diet feeding.…”

'Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis

“…Moreover, despite numerous studies that found that an HP diet increases GFR ( 30 , 33 , 49 , 53 , 70 , 71 ), to date there is no evidence linking HP intake to kidney disease in healthy individuals or those at risk of kidney disease due to pre-existing conditions such as obesity, hypertension, or dyslipidemia ( 62 ). Furthermore, animal studies have shown that markers of renal damage do not differ in obese rats fed a high-mixed-protein diet for 12 wk as compared with those fed a lower-protein diet, despite an increase in kidney size ( 72 ). In addition, monocyte chemoattractant protein 1 (MCP-1) concentration, a known mediator of kidney disease susceptibility ( 73 ), was lower in the high-mixed-protein group ( 72 ).…”

“…Furthermore, animal studies have shown that markers of renal damage do not differ in obese rats fed a high-mixed-protein diet for 12 wk as compared with those fed a lower-protein diet, despite an increase in kidney size ( 72 ). In addition, monocyte chemoattractant protein 1 (MCP-1) concentration, a known mediator of kidney disease susceptibility ( 73 ), was lower in the high-mixed-protein group ( 72 ). These animal data again highlight that increased kidney size and GFR are not linked to kidney damage and disease.…”

CCAP regulates feeding behavior via the NPF pathway inDrosophilaadults

“…Deficient intake of macronutrients can cause several problems, such as reduced energy, growth defects, hypoglycemic seizures, and liver or heart damage (1-3). On the other hand, high-sugar intake possibly leads to decreased insulin sensitivity, high-protein consumption leads to kidney disease, and a high-fat diet can cause chronic inflammation, which itself can lead to type 2 diabetes (4)(5)(6)(7)(8). While many known regulators of food intake have been implicated in affecting macronutrient consumption, such as neuropeptide Y (NPY), proopiomelanocortin, and galanin, this topic has been difficult to study and various research groups have used different conditions for testing macronutrient selection (9)(10)(11).…”