I was diagnosed with stage 4 kidney disease about two years ago. My kidney doctor couldn’t figure out why, since I didn’t have hypertension or diabetes. I did my own research and figured that it was the smoothies that I had almost every day (for three years) which contained one cup of spinach. Spinach is one of the foods with the highest amount of oxalates. I changed my diet and and my last blood work was normal. I couldn’t post a link to a research article because I am a new member, but you can search for “Diet-induced oxalate nephropathy from excessive nut and seed consumption”.