Based on my research, here's what you need to know about sourdough bread and CKD in IgA Nephropathy:

Sourdough bread can be a better choice than regular bread for CKD patients because:
1. The fermentation process reduces phosphorus content
2. It has a lower glycemic index
3. The probiotics may help gut health

However, watch your portions and sodium content. Choose whole grain sourdough when possible, and always check with your doctor about specific serving sizes that work for your condition.