We often get the question about soy milk versus cow’s milk in the kidney diet. “Which is better for a person with chronic kidney disease?” was prompted when he substituted soy milk for cow’s milk in his favorite Starbuck’s coffee drink. Soy milk is made from soy beans, and any bean product is potentially a food higher in potassium and high in phosphorus.
Check the Nutrition Label
However all products are not created equal. Soy milk brands vary in potassium, phosphorus, calcium and sodium so it is essential to check the nutrition label and ingredients list. The nutrition label is now required to have the potassium listed in milligrams.
In some cases the label may include phosphorus expressed as a percentage of the Daily Value, which is the percent of a nutrient recommended based on a 2000 calorie healthy diet (5% or less is low and equals 50 mg phosphorus and 20% or more is high and equals 200 mg (milligrams) phosphorus). For people with kidney disease the lowest phosphorus-containing milk substitute is best.
Potassium, Phosphorus, Sodium, Calcium and Protein in Soy Milk
The nutrient values for an 8 ounce serving (240 ml) of several soy milk brands vary by brand, so aim for the lowest potassium, sodium, and calcium level. Also avoiding phosphorus additives in the ingredient list.
- Potassium range estimates: 240-400 mg
- Phosphorus range estimates: 100-250
- Sodium range estimates: 90-145 mg
- Calcium range estimates: 40-450 mg
- Protein range estimates: 6-8 grams
Benefits of Soy Milk
Replacement of animal protein with plant protein like soy in the kidney diet can reduce protein loss in the urine (proteinuria). This is attributed to phytoestrogens from soy and may help preserve kidney function for those with chronic kidney disease not yet on dialysis, and be a healthy food choices for those on dialysis. In addition to soy milk, kidney disease patients can explore other soy products like soy protein powder, nutrition bars with soy, tempeh, tofu and meat analogs made with soy. Work with your renal dietitian to see which of these foods for kidney health fit into your individual renal diet.
References:
"Protective effects of Dietary Phytoestrogens in Chronic Renal Disease" in the Journal of Renal Nutrition, Vol 11, No 4 (October) 2001: pp 183-193.
Zhou Jing, Yuan Wei-Jie. Effects of soy protein containing isoflavones in patients with chronic kidney disease: A systematic review and meta-analysis. Clinical Nutrition. Volume 35, Issue 1, 2016, Pages 117-124. https://www.sciencedirect.com/science/article/abs/pii/S0261561415000874. Accessed September 9, 2026.
