Q&A: Keto diet intervention effective in small study of patients with glioma
Patients with glioma who completed the 8-week GLioma Atkins-based Diet experienced “meaningful” ketonuria and significant systemic and cerebral metabolic changes, according to results from a small study published in Neurology.
The GLioma Atkins-based Diet (GLAD) intervention involved two fasting days, in which calories were restricted to 20% of calculated, estimated needs, and five modified Atkins diet days, with a net carbohydrate intake of 20 gm/day. Among the 25 patients with glioma participating in the diet intervention, 84% completed the study due to the “demanding” diet regime. Those who did complete the intervention experienced ketonuria that correlated with cerebral ketone concentration.
Healio Neurology spoke with Karisa Schreck, MD, PhD, assistant professor of neurology, oncology and neurosurgery at Johns Hopkins University School of Medicine, and Roy Strowd, MD, MS, MEd, associate professor of neurology and oncology at Wake Forest School of Medicine, about the study results and the implications of the findings for patients with glioma.
Healio Neurology: What prompted this research?
Schreck and Strowd: There has been a long interest in targeting metabolic pathways that are involved in cancer and glioma specifically. Few therapies are available today that can be brought into the clinic, but ketogenic dietary interventions have been used safely for over a century in neurology and clinical medicine. Quite frankly, many patients are already exploring and doing this type of dietary intervention for their seizures or cancer and we felt an obligation to study this therapy more closely so that we can understand whether it is safe, when it could be incorporated best into existing treatment regimens, and whether it is effective for patients with gliomas.
Healio Neurology: Can you discuss the major themes that emerged?
Schreck and Strowd: This study was intended to determine whether a rigorously defined ketogenic diet was safe, could be maintained in patients with a brain tumor and what the effects were on systemic metabolism as well as cerebral metabolism. Evaluating the activity of this dietary intervention on the brain and in the area of the treated brain tumor was an important goal and secondary objective of the study.
Healio Neurology: What were the primary take-home messages?
Schreck and Strowd: There are at least three important take-home messages. First, we found that while only 48% of glioma patients were able to maintain the strict dietary requirements according to their food records, over 80% of patients achieved ketosis, indicating that the diet had the anticipated effect. Second, we found that the diet was well tolerated and safe. While total body weight did decline during the study, lean body mass, which we tend to think of as largely muscle mass, increased. Third, specialized brain scans called MR spectroscopy detected changes in brain metabolites, including an increase in the concentration of ketones and metabolic changes in the tumor region.
Healio Neurology: What specific strategies would you suggest, based on your conclusions that efforts are needed to improve the delivery of care?
Schreck and Strowd: We still have a long way to go before this type of therapy is ready for prime time for patients. Since we began this study, there have now been a number of additional studies evaluating ketogenic dietary therapies for brain tumors. The findings in many of these studies are largely mixed and this may have to do with many factors, including the wide variety of dietary interventions that have been used. This 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 could be incorporated best into treatment.
Healio Neurology: Is there anything unusual or surprising about the results that you would like to elaborate on?
Schreck and Strowd: It is important to note that we screened a lot of patients to complete the study and those patients who did go on study were seen by a dietitian every 2 weeks to help them learn how to implement this treatment safely.
Healio Neurology: What are the next steps for this research?
Schreck and Strowd: There is still a lot of work to do. This study was designed at a unique time after patients had completed traditional treatment for their tumor and as a potential maintenance strategy. The study was not designed to determine whether the diet improves survival. These questions still need to be answered.