Ketogenic diet interventions (KDIs)—which, instead of drawing fuel from glucose obtained from carbohydrates, drive the body to use ketone bodies produced by the liver from stored fat—limit protein intake, and some studies have shown some possible health risks associated with prolonged adherence. But there are also benefits associated with this diet plan, including weight loss.

Lab work in animal models by Sebatian Strubl, MD, and colleagues has suggested that KDIs or time-restricted diets (TRDs) may lessen autosomal dominan polycystic kidney disease (ADPKD) progression. The lining cells of the cysts in polycystic kidney disease (PKD) rely on glucose as an energy source, and mouse models have shown that a restriction of this energy source can decrease renal cyst growth. “Our findings indicated that PKD cysts cannot adapt to the metabolic changes in ketosis, which could potentially be exploited therapeutically,” wrote Dr. Strubl and colleagues in Clinical Kidney Journal.

Given the aims of a KDI, Dr. Strubl and colleagues conducted a study to examine the effects of dietary intervention in patients with ADPKD. Focusing primarily on KDI and TRD, they carried out an uncontrolled, unbalanced case series study that retrospectively collected and analyzed patient-reported observations and self-reported medical data before and during the implementation of KDIs.

The study cohort included 131 patients with ADPKD who had tried KDI diets previously—including variations of KDIs as well as TRDs and calorie-restrictive (CR) diets. The patients were mainly based in the United States and were separated by diet: 74 followed a KDI, 52 a TRD, and five a CR diet. More than one-half of the KDI group also applied a TRD or CR to their dietary practice. Participants followed KDIs for an average of 6 months.

Improved Health Issues for Patients With ADPKD

Eighty percent of participants on KDIs reported improvements in their well-being (Figure). A total of 11 participants reported recurrent health issues (HIs) before starting KDIs; of them, 67% reported improvement after starting the diet plan, and more than 50% of all HIs were improved.

Weight loss was also a positive outcome associated with KDI, with about 90% of participants reporting weight loss (average, 9.1kg). Participants reported experiencing rapid weight loss within the first few weeks that leveled off for 66% and continued for 34%.

Among the 74% of participants who reported hypertension, 64% re- ported improvements in their blood pressure (BP) with a KDI. Self-reported BP values showed a considerable decrease in average from 132/85 mm Hg to 118/76 mm Hg in participants adhering to the KDI. Of the 70 KDI participants who provided data on estimated glomerular filtration rate (eGFR), 45 reported an improvement, eight had no change, and 17 had a decline.

Sixty-six percent of participants reported an average of 2.6 new HIs while on KDIs. Of these, fatigue, hunger, and “keto flu” were the most common. Fifty-five percent of participants with new HIs reported that these subsided over time, and 12% reported that these new HIs persisted.

Implementation of the KDI was manageable, according to 76% of participants; 50% of participants adhered to the diet daily and 42% skipped diet adherence several times a month.

Safety Concerns & Considerations

Among participants, 22 experienced changes that raised safety concerns; the most common was increased cholesterol. Data provided by the participants indicated an average increase in total cholesterol of 13 mg/dL and in LDL levels of 8.5 mg/dL. Increases were significantly higher in the KDI group. One participant reported kidney stones, and two reported an increase in serum creatine.

The research team acknowledged that because all the information was self-reported, the reliability and interpretation of the data may be limited.