Abstract
Introduction: High protein intake can accelerate kidney disease. Soy protein diet has been reported to reduce the progression of chronic kidney disease (CKD) compared to a milk (casein) protein diet. Sex differences play a key role in kidney function and disease with premenopausal women having fewer kidney diseases compared to age-matched men. The purpose of this study was to compare the effects of high soy protein consumption with that of high casein consumption on renal protein excretion in male and female mice. We hypothesized that sex differences exist in the renal handling of these two protein sources.
Methods: Two separate studies, one with male mice and one with female mice, were conducted. Mice at 25 days of age were placed in metabolic cages. After a baseline period of three days on standard diet, one group consumed 40% casein and the other an isocaloric 40% soy diet for 25 days (n=6 per group). Daily measurements included body weight, food and water intake, urinary flow rate (UFR), and urinary protein excretion (UPE) via dipstick analysis. UPE (mg/day) was also determined on the final day of each study by measuring total urine protein concentration (TPC) and calculating UPE (UPE = TPC x UFR).
Results: Independent of the diet, females excreted significantly less protein compared to males despite equal protein consumption. Regardless of sex, the casein groups excreted more protein than the soy groups via dipstick measurement. UPE (mg/day) measured on the 25th day was higher in the casein groups compared to the soy groups (males: 31.9 ± 2.5 vs. 17.8 ± 0.9, p<0.009; females: 10.2 ± 1.7 vs. 5.4 ± 0.8, NS).
Conclusion: We conclude that high soy intake induces less proteinuria compared to that with high casein intake. Female mice on high casein and high soy diets excreted less protein when compared to male mice on the same diet. These results support the benefits of soy protein in patients with kidney disease and indicate sex differences in the renal handling of high protein diets.
Methods: Two separate studies, one with male mice and one with female mice, were conducted. Mice at 25 days of age were placed in metabolic cages. After a baseline period of three days on standard diet, one group consumed 40% casein and the other an isocaloric 40% soy diet for 25 days (n=6 per group). Daily measurements included body weight, food and water intake, urinary flow rate (UFR), and urinary protein excretion (UPE) via dipstick analysis. UPE (mg/day) was also determined on the final day of each study by measuring total urine protein concentration (TPC) and calculating UPE (UPE = TPC x UFR).
Results: Independent of the diet, females excreted significantly less protein compared to males despite equal protein consumption. Regardless of sex, the casein groups excreted more protein than the soy groups via dipstick measurement. UPE (mg/day) measured on the 25th day was higher in the casein groups compared to the soy groups (males: 31.9 ± 2.5 vs. 17.8 ± 0.9, p<0.009; females: 10.2 ± 1.7 vs. 5.4 ± 0.8, NS).
Conclusion: We conclude that high soy intake induces less proteinuria compared to that with high casein intake. Female mice on high casein and high soy diets excreted less protein when compared to male mice on the same diet. These results support the benefits of soy protein in patients with kidney disease and indicate sex differences in the renal handling of high protein diets.
| Original language | American English |
|---|---|
| Journal | Oklahoma State Medical Proceedings |
| Volume | 3 |
| Issue number | 3 |
| State | Published - 8 Nov 2019 |
Keywords
- High protein diet
- Urinary Protein Excretion
- Casein
- Soy
- Sex differences