Brain Tumor - Glioblastoma
Dietary and Lifestyle Considerations
The American Cancer Society and American Brain Tumor Association have several dietary and lifestyle recommendations for cancer patients. Good nutrition can help patients manage the side effects of cancer treatment, maintain energy (Toles 2008), avoid infections (Di Furia 2015), and even fight the disease. In general, patients’ diets should be rich in a variety of vegetables and healthy sources of protein and unsaturated fats (ACS 2015; Vanderwall 2012; Toles 2008). For some patients, an exercise program may improve mood and quality of life (Levin 2016).
The ketogenic diet emphasizes healthy fats and proteins with very little carbohydrates (typically less than 20 grams net carbohydrates daily) (Winter 2017; Paoli 2015; Westman 2008). This diet is sometimes recommended to reduce seizure frequency in children and adults with epilepsy, but may also be helpful in those with glioblastomas because these tumors are known to rely on carbohydrates for energy (Varshneya 2015; Winter 2017).
A ketogenic diet has been found to control tumor growth and prolong survival in animal studies (Varshneya 2015; Klement 2016). Other studies have found that the diet may boost immune response to tumor cells and provide benefits when used in combination with other treatments, such as radiation (Lussier 2016). In humans, the diet is well tolerated and safe (Champ 2014). Blood tests can be used to check how well the diet is reducing blood glucose levels and increasing ketone levels (Meidenbauer 2015). Several phase I or II interventional trials have been conducted or are underway to investigate whether a ketogenic diet can improve outcomes for people with glioblastoma (Lin 2016; Klein 2016a; Klein 2016b; Martin-McGill 2017).
Some research has suggested restricting caloric intake may enhance the effects of a ketogenic diet (Maroon 2015; Seyfried 2012). Caloric restriction may be accomplished by reducing daily intake or by intermittent fasting. However, patients with advanced cancer should work with a nutritional oncologist to ensure they are consuming adequate nutrition (Maroon 2015).
Coffee and Tea Consumption
Coffee and tea have also been explored as a potential dietary intervention for reducing the risk of developing gliomas. In a large study of participants from 10 European countries, daily intake of 100 mL (about half a cup) or more of coffee or tea was associated with a lower risk of developing glioma. The association was slightly stronger in men (Michaud 2010). This same beneficial effect was reported in another study that examined the intake of coffee and tea in people from the United States. This US-based study reported that those drinking five or more cups of coffee and/or tea per day were less likely to develop gliomas than those who drank less than one cup per day (Holick 2010).
Coffee contains a compound called chlorogenic acid, which has been shown to inhibit glioblastoma cell growth in laboratory studies (Xue 2017; Belkaid 2006). Other compounds in coffee include kahweol and cafestol, which have been shown in animals to increase the activity of MGMT, which is commonly silenced in glioblastoma cells (Huber 2003). Additionally, one of the molecules found in tea, called epigallocatechin gallate (EGCG), can reverse the silencing of MGMT in cell culture experiments (Fang 2003). EGCG has also been shown to improve the efficacy of temozolomide in a mouse glioblastoma model (Zhang 2015; Chen 2011).