Keto diets a ‘double-edged sword’ in fighting cancer, research suggests
The ketogenic diet is high-fat, moderate-protein, and low-carbohydrate. The idea of eating this way, is that the body burns ketones – produced in the liver from fat – rather than carbohydrates.
The diet appears to be growing in popularity, with an estimated 23m people following a ketogenic diet in the US alone, according to the International Food Information Council.
Proponents of the diet say health benefits associated with the trend range from supporting weight loss to reducing ‘brain fog’. But recently, another potential health benefit has been linked to the ketogenic diet.
Recent studies have indicated that a ketogenic diet can be used as an adjuvant therapy to enhance sensitivity to chemotherapy and radiotherapy in cancer patients. But it may not be all good news, according to new research out of the UK, US and Singapore.
The double-edged sword
The idea of using ketogenic diets to boost efficiency of cancer therapy stems from speculation that cancers feed on sugar. Since the keto diet is low carbohydrate, it has been suggested that tumours can be ‘starved’ of its energy source for improved clinical outcomes.
In their recent study published in Cell Metabolism, researchers demonstrated in two different experimental models that keto diets can indeed slow cancer growth.
But they also found that the keto diet can act as somewhat of a ‘double-edged’ sword. Unexpectedly, the diet also accelerated a ‘wasting syndrome’ known as cachexia, which worsens the disease prognosis. In mice, tumour growth was delayed, but cachexia onset accelerated and shortened survival in mice fed a ketogenic diet.
“Special diets may help to make cancer therapy more effective. However, our research highlights that dietary interventions affect many organ systems beyond just cancer cells, leading to both deleterious and positive consequences,” explained co-author Prof Venkitaraman, director of the Cancer Science Institute of Singapore at the National University of Singapore.
“The mechanism we have identified raises critical questions regarding the use of high-fat or starvation diets in the treatment of cancer. Further investigation is needed to fully understand the balance of benefits and risks associated with these dietary approaches.”
A potential solution
The researchers also found that administering dexamethasone, a potent glucocorticoid which improves appetite and increases endogenous glucose production, can delay the onset of cachexia and extend the survival of tumour-bearing mice following a keto diet.
It has been suggested that taking such drugs may allow suppression of tumour growth, but without developing the ‘wasting syndrome’.
“Our study emphasises the need to investigate the effects of systemic interventions on both the tumour and the host to accurately assess therapeutic potential,” noted the study authors.
“These findings may be relevant to clinical research efforts that investigate nutritional interventions such as ketogenic diets in patients with cancer.”
What else does the science say?
The study contributes to an ever-growing pile of scientific research into the health impacts – both positive and negative – of following a keto diet.
According to research out of Poland, for example, the keto diet may aid neurological diseases, specifically in patients with neurological problems associated with increased oxidative stress and neuro-inflammation or disruption in brain energy metabolism.
A study out of Canada has also suggested a ketogenic drink could improve cognitive function in individuals suffering from Mild Cognitive Impairment.
But it may not be all good news. In sport, it has been suggested that keto could benefit endurance athletes, by making their fat reserves more readily available. But in a review published in Journal of the International Society of Sports Nutrition in 2020, study authors concluded that the science could not – at least for the moment – support the use of ketogenic diets for improvement in performance in endurance events.
Nutrition experts have raised concerns that following a keto diet could damage liver heath, and more specifically, put followers at higher risk of developing non-alcoholic fatty liver disease.
And most recently, a study out of Nagoya University Graduate School of Medicine in Japan found that low carbohydrate intake in men (but not specifically a ketogenic diet) was associated with higher risk of all-cause and cancer-related mortality.
Source: Cell Metabolism
‘Ketogenic diet promotes tumor ferroptosis but induces relative corticosterone deficiency that accelerates cachexia’
Published 11 July 2023
DOI: https://doi.org/10.1016/j.cmet.2023.05.008
Authors: Miriam Ferrer, Nicholas Mourikis, Tobias Janowitz et al.
