Ketogenic dietary interventions are known to be beneficial in animal models of autosomal-dominant polycystic kidney disease (ADPKD), the most common hereditary kidney disease worldwide, which causes 5 to 10% of all cases of kidney failure.
KETO-ADPKD, an exploratory, randomised, controlled trial conducted by researchers at University Hospital Cologne and the Aging Research Excellence Cluster CECAD of the University of Cologne, set out to provide clinical translation of these findings.
Participants were divided into three groups: one followed a ketogenic diet for three months, the second did three days of water fasting once a month – a kind of zero diet that only allows drinking water – and a third control group followed standard dietary recommendations.
As many as 95 per cent of patients in the ketogenic group and 85 per cent in the water fasting group reported the diet to be feasible – an important finding, given scepticism about how realistic the regimen is for everyday life.
Ketogenic diet reported by patients as ‘feasible’ dietary intervention
The ketogenic diet is very low in carbohydrate, modest in protein, and high in fat. Its aim is to mimic the metabolism of the fasting state to induce ketosis, the production of ketone bodies that serve as an alternate energy source for neurons and other cell types that cannot directly metabolise fatty acids.
Research group leader Professor Roman-Ulrich Müller, who presented the results during “Kidney Week” at the American Society of Nephrology last month, said: “You have to skip bread and sweets, and, for example, you use more olive oil – fatty fish such as salmon are also a great food in this regard.”
It has been established as a successful dietary approach for treating intractable epilepsy and has garnered attention over the past decade for its role in other chronic conditions, with emerging evidence of its promising therapeutic potential for diseases including obesity, diabetes, and malignancies.
Ketone bodies measured in participants’ blood samples showed that they had adhered to the prescribed diet, the study, in Cell Reports Medicine, found.
Positive changes in kidney function seen after three months
After three months, positive changes in important parameters such as kidney function were seen, and there were no unexpected side effects. The positive changes in kidney function were statistically significant and exceeded the expectations of the researchers.
Müller said the results were an important step for the development of a possible new treatment for polycystic kidney disease.
However, he conceded that these data from a phase II-like design study were not yet sufficient to generally recommend the ketogenic diet for patients with polycystic kidney disease. Further larger studies at multiple sites are needed to confirm the results and to clarify whether sustained improvements in kidney function can be achieved long term.
In general, however, the present study is important because, thanks to its design in analogy to a drug trial, it proves that food can be as effective as a drug, Müller argued.
He said: “This could be the starting point for many dietary treatment strategies.”
