Effects of processed low-protein brown rice on patients with chronic kidney disease

Alterations in gut microbiota are prevalent in patients with chronic kidney disease (CKD) and are associated with pathogenic phenotypes, including the progression of kidney damage and defecation conditions. We developed a fermented low-protein brown rice (LPBR), a whole grain unpolished rice, and examined its effects on renal function, defecation condition, and gut microbiota composition in CKD patients.

In this 3-month, single-arm study, 30 outpatients with stage 3 - 4 CKD were recruited and received a dietary intervention with LPBR. Changes in the defecation condition were evaluated using the Constipation Scoring System (CSS) and the Bristol Stool Form Scale. Alterations in urinary protein excretion and estimated glomerular filtration rate (eGFR) as well as stool condition were assessed as primary outcomes.

Among the 29 participants with CKD, intervention with LPBR led to a significant improvement in CSS scores (P = 0.023), a reduction in urinary protein excretion (P = 0.050), and a decrease in eGFR levels (P = 0.044). Fecal acetic acid increased (P = 0.024) and the abundance of Bifidobacterium longum in the gut microbiota increased (P = 0.094). Changes in Bifidobacterium longum were positively associated with alterations in fecal acetic acid levels and CCS scores. Additionally, changes in fecal acetic acid were positively associated with changes in eGFR and Bristol stool scores.

The trend toward increased Bifidobacterium longum abundance and elevated acetic acid production with LPBR intake may contribute to the attenuation of CKD complications. Our findings suggest that LPBR intervention may offer beneficial effects for CKD patients.