Ketogenic, Intermittent-Fasting Diet Feasible for Patients With Glioma

By Lisa Rapaport

July 08, 2021

(Reuters Health) - A modified Atkins diet combined with intermittent fasting appeared feasible and able to produce systemic biological activity and cerebral activity in patients with glioma, a small study suggests.

Researchers enrolled 25 patients with biopsy-confirmed glioma who completed adjuvant chemotherapy in an 8-week dietary trial that required them to follow a modified Atkins-style ketogenic diet five days a week and then have two fasting days when they consumed just 20% of their estimated caloric needs. The primary goal of the study was to assess dietary adherence based on food intake records.

Dietary adherence was defined as compliance with the modified Atkins diet based on intake of no more than 20 grams of net carbohydrates daily, compliance with calorie limits on fasting days, and no days with 40 grams or more of net carbohydrates. Overall, 21 patients completed the study and 12 patients (48%) were compliant with all aspects of the diet based on food records.

In addition, 18 patients (72%) adhered to both the modified Atkins diet and the intermittent fasting but were not counted as completely compliant due to one day with at least 40 grams of carbohydrates.

"Our study is an important step toward evaluating a rigorously defined dosing strategy of the diet, but more work is needed to determine whether this type of diet will be helpful for patients and if so, when it should be incorporated best into treatment," said senior study author Dr. Roy Strowd of Wake Forest School of Medicine in Winston-Salem, North Carolina, and lead study author Dr. Karisa Schreck of Johns Hopkins University School of Medicine in Baltimore.

The diet appeared well-tolerated, the researchers report in Neurology. Twelve patients had grade 2 adverse events including leukopenia, nausea, diarrhea, fatigue, or seizure, while one patient had grade 3 neutropenia that was deemed possibly related to the intervention and one had grade 3 seizures deemed not related.

Secondary endpoints of the study included markers of systemic and cerebral activity such as weekly urine ketones, serum insulin, glucose, hemoglobin A1c, IGF-1, and MR spectroscopy.

Four in five patients achieved at least moderate ketonuria, defined as at least 30 mg/dL, at some point during the eight-week study period. Researchers also found a significant increase in cerebral ketones.

"Importantly, we did see changes in brain metabolites," Dr. Strowd and Dr. Schreck said by email. "But more study is needed to determine whether this diet can prevent the growth of tumors and improve survival."

Beyond its small size, another limitation of the study is the potential for participant self-selection to influence the outcomes. Patients who agreed to enroll may not be representative of all glioma patients, the study team notes.

"In this highly motivated group of patients, only half were able to be fully compliant with this diet even when supported by the study staff and a registered dietician," said Dr. Lynne P. Taylor, a clinical professor in neurology and co-director of the Alvord Brain Tumor Center at the University of Washington Medical Center in Seattle.

"This should make it clear that it is not yet possible to safely make this diet part of treatment for brain tumor patients until we can prove that it is definitely beneficial in slowing down the rate of tumor growth - something that is currently just a theory," Dr. Taylor, who wasn't involved in the study, said by email.

SOURCE: Neurology, online July 7, 2021.