Is the very low carbohydrate diet safe for individuals with chronic kidney disease?

Abstract

Background: The very low carbohydrate diet (VLCHD) is gaining popularity as a therapy for metabolic syndrome. However, its effect on renal function in patients with comorbid moderate to severe chronic kidney disease (CKD) is currently unclear.

Aim: This study analyses markers of kidney function in patients with metabolic syndrome and stages 3 and 4 CKD who undertook a VLCHD for at least 3 months.

Setting: The study was conducted in a Mid North Coast general practice located in Port Macquarie, NSW, Australia, 2020–2022.

Methods: Clinical data were analysed retrospectively from 18 participants with metabolic syndrome and CKD stages 3 and 4, who were prescribed a VLCHD (< 30 g carbohydrates/day). A linear mixed model was used to analyse markers of metabolic health (glycated haemoglobin (HbA1C), body mass index (BMI), blood pressure (BP), lipid profile (triglycerides and low-density lipoprotein cholesterol) and kidney function (estimated glomerular filtration rate (eGFR), serum creatinine, bicarbonate and urea)).

Results: Strong evidence was found for reduced BMI (p < 0.001) and HbA1c (p < 0.001), despite reduced diabetic medications in 13/14 participants. Antihypertensive medications were reduced in 6/14 participants with no change in systolic BP. No changes were detected in eGFR or bicarbonate, while creatinine (p ≤ 0.001) and urea (p = 0.002) were reduced. No participants deteriorated to a more advanced stage of CKD; rather an absolute eGFR increase was found in 15/18 participants.

Conclusion: For the first time, the VLCHD was demonstrated to reduce BMI, HbA1c, BP and medication burden in patients with CKD stages 3–4 without evidence of kidney damage.

Contribution: The VLCHD could be a safe and effective therapy to improve metabolic health and consequently reduce cardiovascular disease risk in patients with metabolic syndrome and CKD.