The effects of soy protein and soy isoflavones intake on chronic kidney disease: a systematic review and meta-analysis.

Purpose: Existing literatures on the potential impact of soy protein consumption on kidney function present conflicting findings. In this study, a meta-analysis has been conducted to assess the impact of soy protein consumption in comparison to animal protein consumption among individuals with chronic kidney disease (CKD).

Methods: A structured electronic search was conducted on Medline, EMBASE, and Cochrane Library for randomized controlled trials published up to March 2024. The outcome measures were serum creatinine (SCR), triglyceride (TG), total cholesterol (TC), calcium (Ca), C-reactive protein, proteinuria, high-density lipoprotein (HDL), low-density lipoprotein (LDL), uric acid (UA) and phosphorus concentrations. Mean differences were calculated for net changes using random-effects models.

Results: Eighteen trials with a total of 522 participants were included in this systematic review. The results showed that consumption of soy protein led to a significant decrease in total cholesterol, LDL, and proteinuria levels. The average reduction was  - 20.55 mg/dL (95% CI  - 38.25,  - 2.85 mg/dL) for total cholesterol (P = 0.02),  - 8.26 mg/dL (95% CI  - 13.35,  - 3.17 mg/dL; P = 0.001) for LDL and  - 140.53 (95% CI  - 205.83,  - 75.23 mg/day) for proteinuria. No statistically significant impact was observed on serum creatinine, triglycerides, calcium, C-reactive protein, HDL, uric acid, or phosphorus levels.

Conclusion: The findings of the meta-analysis showed a potential protective impact of soy protein intake on hyperlipidemia and proteinuria in CKD patients. It is important to note that the evidence presented may be of limited accuracy due to relatively small number of trials and participants.