Diet Therapy Can Improve Renal Function in Patients With CKD

A study published in The British Journal of Nutrition found that diet therapy with supportive education and counseling could help improve renal health, blood pressure control, and adherence to protein intake in patients with stages 3 and 4 chronic kidney disease (CKD). Investigators also observed a significant difference in mean glomerular filtration rate (eGFR) between the intervention and control groups.

The study took place over 24 weeks and included patients with stages 3 and 4 CKD without comorbidities. Patients were recruited from July to August 2019 from the Shahid-Faghihi and Shahid-Motahrai outpatient clinics in Iran. Patients were excluded if they had an infection, Alzheimer disease, AIDS, malignancy, diabetes, cancer, heart failure, impaired cognitive function, or a mental disorder, or if they were on dialysis, had experienced a rejected kidney transplant, or were pregnant or planning to become pregnant.

Patients self-reported their dietary adherence, which ranged from 80% to 90%. Participants were also contacted through a telephone call for 20 minutes once a week. Patients were required to provide a 3-day food recall on the first and final days of the trial, which was collected by a trained dietitian in an interview.

Dietary counseling was an individualized dietary program that was formulated by a renal dietitian. The dietary intake considered for this study included moderate protein consumption of 0.75 g per desirable body weight per day, energy consumption based on patient’s nutritional status, and low sodium intake of less than 2000 mg a day. Different educational strategies were also offered to the intervention group, including face-to-face meetings to discuss their dietary habits.

There were 105 patients who completed the trial. The mean (SD) age of the patients was 50.18 (1.96) years in the intervention group and 49.43 (1.85) years in the control group.

The researchers found that there was a significant difference in eGFR, blood urea nitrogen (BUN), and creatinine (Cr) serum level at the end of the study between the 2 groups. Mean (SE) eGFR increased significantly in the intervention group (2.8 [0.8]) compared with the control group (–2.7 [1]). Nutrition was also found to hinder the mean (SE) increase in BUN level in the intervention group (0.1 [0.7]) compared with the control group (3.6 [1.4]). A significant decline in Cr serum level was found in the intervention group (–0.09 [0.1]).

Systolic blood pressure and diastolic blood pressure also decreased significantly in the intervention group (–7.8 [1.6] and –3.3 [1.2], respectively) and depression scores were higher in the control group compared with the intervention group (1.3 [0.2] vs 0.3 [0.2]).

There were some limitations to this study. There was only a single measurement of serum Cr and BUN during the period of the study. Urinary protein and urea were not measured during the study. The relative lack of clinician contact and support for the control group compared with the intervention group could have affected the results. The participants were entirely patients with CKD who did not have comorbidities, which makes it hard to generalize the findings to patients with complex CKD.

The researchers concluded that nutritional treatment with supportive education and counseling contributed to significant improvements in renal function.

Reference

Hamidianshirazi M, Shafiee M, Ekramzadeh M, Jahromi MT, Nikaein F. Diet therapy along with nutrition education can improve renal function in people with stages 3-4 chronic kidney disease who do not have diabetes (a randomized controlled trial). Br J Nutr. Published online July 7, 2022. doi:10.1017/s0007114522002094