The Ketogenic Diet and Cancer
Over the last few years, the ketogenic diet has become a popular diet to lose weight. While the diet is challenging to implement and carries some risks and side effects, data is starting to suggest that it may have applications for treating some health conditions, including cancer.
What Is the Ketogenic Diet?
If you haven’t heard of the ketogenic diet, it’s worth briefly explaining the history and principles around inducing “ketosis.” The diet was initially developed in the 1920s for the treatment of intractable seizures in children. At the time, there were few viable treatment options for seizures. Historical reports back to Hipocrates, recommended fasting as a treatment approach (Bailey 2005). Based on these reports of positive outcomes, around the end of World War I, Dr. H.R. Geyelin at the Presbyterian Hospital in New York City started treating epilepsy patients with fasting. During a strict fast, and for a time afterwards, seizure patients would often remain seizure free (Geyelin 1921).
At the time, it was known that fasting induces a ketogenic state or ketosis. When carbohydrates are no longer available for energy production, cells in the body switch to processing fat for energy. Based on the idea that ketosis was the reason why fasting was beneficial for seizures, Dr, H.R. Wilder proposed a study. He treated patients with severe seizures using a diet almost devoid of carbohydrates. The diet eliminated grains, beans, fruit, sugar and other starchy foods (Wilder 1921). Eliminating carbs and sugars effectively induces ketosis and has similarities with fasting. The diet proved to be effective. To this day, ketogenic diets are still utilized in cases of intractable seizures, often in children.
Cancer and Sugar
At around the same time, Otto Warburg, a renowned physician and researcher, noted something peculiar about cancer cells. Called the Warburg effect, Warburg noted that cancer cells utilized sugar for fuel primarily through an inefficient process of fermentation, similar to yeast (Chen 2007). While a bit of an oversimplification, research has confirmed that many cancers due rely heavily upon sugar fermentation to survive. To this day, targeting the fermentation pathway of energy production has been suggested as a promising approach to cancer treatment (Mirzaei 2020).
Ketogenic Diet, Ketosis and Cancer
As a corollary, a simple approach to reduce energy production in cancer cells is to eliminate the availability of sugar. The ketogenic diet, in theory, is one such approach. With reduced availability of carbohydrates and sugar, you starve cancer cells. Brain, head, neck and lung cancers are often heavily reliant on sugar for energy. While not all cancer cells rely heavily on fermentation, many common cancers do (Bozzetti 2020).
Ketogenic Diets and Malignant Gliomas (Brain Cancer)
Malignant gliomas are often fatal. They account for 75% of all brain cancers. Only 5% of patients diagnosed with a malignant glioma will be alive five years later. In addition, no current therapy is considered potentially curative (Finch 2021). Interestingly, malignant gliomas rely heavily on fermentation as a source of energy. As such, malignant gliomas have been one of the most frequent cancers where the ketogenic diet has been utilized.
While the current research results have not definitively documented benefits, they do at least outline safety and feasibility. Some of the biggest challenges are due to adherence, since ketogenic diets are difficult to implement for many patients. Due to the challenges, drop-out rates are often quite high in the research literature (Thomas 2020). However, there remains an interest in using ketogenic diets for malignant gliomas based on the poor results of standard therapies.
Ketogenic Diets and Other Types of Cancer
Human studies are needed to evaluate the effects of the ketogenic diet in other forms of cancer as well. Currently, animal studies show promise in prostate, lung, stomach and pancreatic cancer (Khodadadi 2017). The studies found slower tumor growth and increased survival time for animals following a ketogenic approach. However, it’s worth noting that animal studies don’t always guarantee positive outcomes in humans.
Side effects of the ketogenic diet can occur. During the initiation phase, it’s not unusual for patients to experience flu-like symptoms for a few days. There also appears to be risks for kidney stones and gastrointestinal side effects, including constipation, vomiting and diarrhea (Ułamek-kozioł 2016). Kidney stones may be related to lower mineral intake and increased dehydration caused by ketosis. Bone loss has also been found in children with long-term use, although not generally seen in adults (Bertoli 2014). Increased water intake and supplementation with minerals, especially as citrates, may help decrease these risks, although research is needed for confirmation.
The current data suggests potential benefits of the ketogenic diet for some types of cancer, although human data is extremely limited and somewhat contradictory. At times, I have recommended the ketogenic diet for patients struggling with cancer and intractable seizures. However, it’s not an approach that patients often choose to implement due to the challenges of maintaining such a low carbohydrate diet. Through the ongoing research, we should get a better idea of the potential therapeutic value of ketosis for cancer treatment. Most likely, if effective, it will be an adjunctive therapy to help prolong survival combined with other forms of cancer treatment.