Renal disease is an important cause of morbidity and mortality in Western countries. Dietary changes are fundamental to the management of a large number of chronic nephropaties (1).

It has to be very clear that the understanding of the health effects of soyafoods in patients with renal disease is still in its infancy.
However, integrated analysis of the current knowledge about the nutritional properties of this food, the metabolic derangement and dietary requirements of patients with kidney disease, and the handful of studies that have specifically addressed the issue of soyafoods utilization in renal disease, encourages optimism about the potential beneficial effects of soyafoods in renal patients.

Studies in healthy subjects and in diabetic patients suffering from renal disease, or at risk from it, have shown that soyabean protein-based diets are associated with functional reduction of the glomerular filtration rate, an indicator of glomerular capillary pressure and with reduction of microalbuminuria or proteinuria.
These events are considered beneficial for long term preservation of renal function.

1. The relatively low content of certain amino acids that are biologically active in the kidney
2. The specific sequence of certain digestion peptides that can diffuse from the gut lumen into the portal circulation and seem capable of affecting hepatic function and, indirectly, the renal hemodynamics
3. Certain micronutrients that are unique to soya such, as the isoflavones. 

Kidney dialysis patients run a higher risk of vaso-constriction and increased blood lipid levels. It was shown that soya consumption has a favourable effect on the blood lipid levels of these patients.  The researchers checked various parameters: total cholesterol levels, HDL cholesterol levels and LDL cholesterol levels and apoliprotein B levels. The study established the following results for kidney dialysis patients with high cholesterol levels who consumed 30 g of soya in their daily diet after 12 weeks: a significant decrease of total plasma cholesterol levels, LDL cholesterol and apoB concentrations and a significant increase of HDL cholesterol. No differences were found in the group that consumed milk protein. The researchers also established favourable effects of soya consumption on blood lipid levels in patients with normal blood lipid levels (2).

Fanti et al (3) found in end-stage renal disease patients on chronic haemodialysis that isoflavone-rich soyfoods have beneficial effects on the inflammatory and nutritional status

1. Kopple JD, Massry SG: Nutritional management of renal disease, in, 2nd ed, Philadelphia, PA, Lippincott Williams & Wilkins, 2004, p 682
2. Chen et al. Variable Effects of soy protein on plasma lipids in hyperlipidemic and normolipidemic hemodialysis patients. American Journal of Kidney Diseases 2005;46(6):1099-1106.
3. Fanti P, Asmis R, Stephenson TJ, Sawaya BP, Franke AA. Positive effect of dietary soy in ESRD patients with systemic inflammation--correlation between blood levels of the soy isoflavones and the acute-phase reactants. Nephrol Dial Transplant 2006;21:2239-46.