Exploring the Ketogenic Diet’s Potential in Cancer Therapy
Overview of the Ketogenic Diet
A recent investigation by US researchers examined the ketogenic diet’s potential anti-cancer effects and its application as an adjuvant therapy for cancer. The ketogenic diet, characterized by high fat, moderate protein, and low carbohydrate intake, has gained popularity as a rapid weight-loss strategy. The underlying principle of this diet is to shift the body’s metabolism from carbohydrates to fats, inducing a state known as ketosis. In ketosis, the body utilizes fat as its primary energy source, converting fatty acids into ketones when glucose levels are insufficient. This metabolic shift not only aids in weight loss but has also been utilized in treating conditions such as epilepsy and type 2 diabetes.
Cancer as a Metabolic Disease
Emerging research indicates that cancer may be classified as a metabolic disease, which disrupts normal metabolic processes, particularly how food is converted into energy at the cellular level. Cancer cells tend to favor aerobic glycolysis, a method of energy production that relies heavily on glucose. In contrast, normal cells utilize oxidative phosphorylation, a more efficient process for energy conversion. This distinction suggests that cancer cells thrive on high-glucose diets and could become vulnerable when deprived of glucose.
In healthy individuals, blood glucose levels are meticulously regulated. However, in cancer patients, various factors may facilitate glucose utilization by cancer cells, including a higher concentration of insulin receptors. Consequently, when carbohydrates are consumed, the insulin released can enable cancer cells to access glucose even when overall glucose levels are normal. Additionally, insulin and insulin-like growth factor I (IGF-I) may encourage cancer cell proliferation, indicating that a ketogenic diet could potentially hinder cancer cell growth by limiting glucose availability.
Advantages of the Ketogenic Diet for Cancer Cells
Transitioning the body’s primary energy source from carbohydrates to fats presents multiple challenges for cancer cells. Firstly, many cancer cells rely on aerobic glycolysis and are unable to utilize fats for energy. Secondly, most cancer cells lack the ability to metabolize ketones, which serve as an alternative energy source. Lastly, ketones may inhibit cancer cells from metabolizing glucose, collectively leading to the suppression of cancer cell growth.
Animal Studies on the Ketogenic Diet and Cancer
Research conducted on animal models has demonstrated that adopting a ketogenic diet can significantly impact cancer cell proliferation. These studies have indicated that a ketogenic diet may prevent cancer initiation, inhibit tumor growth, enhance the effectiveness of treatments such as chemotherapy and radiotherapy, and extend survival rates. However, there is a scarcity of research evaluating the ketogenic diet’s impact on human cancer patients. Despite this limited evidence, the existing studies suggest that the ketogenic diet is safe and may offer a beneficial treatment strategy for improving cancer outcomes.
Recent Clinical Trial on Ovarian and Endometrial Cancer
A recent US study investigated the effects of a ketogenic diet on patients with ovarian or endometrial cancer—two of the deadliest cancer types affecting American women. Both cancer types are associated with obesity, which correlates with increased levels of glucose, insulin, and IGF-I. Researchers hypothesized that a ketogenic diet could lower insulin levels and growth factors critical for the proliferation of these cancers. The study’s findings were published in The Journal of Nutrition.
Trial Methodology and Results
The randomized controlled trial involved 45 women aged 19 years and older with ovarian or endometrial cancer and a body mass index (BMI) greater than 18.5 kg/m². Participants were allocated to either a ketogenic diet or the American Cancer Society diet for 12 weeks. The ketogenic diet comprised 70% fat, 25% protein, and 5% carbohydrates, while the American Cancer Society diet was high-fiber and low-fat. Body composition, fasting serum insulin, IGF-I, β-hydroxybutyrate (a ketone marker), and urinary ketones were measured throughout the study.
Results indicated that participants on the ketogenic diet experienced a greater reduction in visceral fat, leading to a lower overall fat mass. These results align with previous studies demonstrating that lower-carbohydrate diets are more effective at reducing abdominal fat compared to low-fat diets in women, particularly those with polycystic ovary syndrome or at risk for type 2 diabetes. Notably, no significant differences were found in lean mass retention between the two groups, indicating that the ketogenic diet helped preserve lean mass, which is crucial for cancer patients prone to sarcopenia.
Insulin Sensitivity and Cancer Proliferation
The study also revealed lower fasting insulin levels among participants on the ketogenic diet, suggesting an improvement in insulin sensitivity potentially linked to reduced visceral fat. However, the precise mechanisms behind this correlation remain unclear. Additionally, lower IGF-I concentrations were observed in patients following the ketogenic diet compared to those on the American Cancer Society diet.
An inverse relationship was noted between IGF-I and β-hydroxybutyrate levels; as IGF-I levels decreased in ketogenic patients, β-hydroxybutyrate levels increased. Previous research indicated that achieving ketosis may correlate with improved cancer outcomes, suggesting that elevated ketone levels could create an environment that limits cancer proliferation.
Study Limitations and Future Research
This study is the first randomized trial to analyze the effects of a ketogenic diet on human cancer patients. However, the diversity among participants in terms of cancer type, treatment history, and concurrent therapies presents a significant limitation that may affect the results. Additionally, as participants were not provided with controlled food, dietary adherence could have influenced the findings.
In conclusion, the study indicated that over 12 weeks, patients with ovarian and endometrial cancer on a ketogenic diet exhibited greater reductions in visceral and total fat compared to those on the American Cancer Society diet, while maintaining lean body mass and demonstrating decreased levels of cancer-related growth factors. Although further research is needed to establish the ketogenic diet as an effective adjuvant treatment for cancer, these initial findings are promising.
Correction Notice
An earlier version of this article inaccurately stated that participants had an average age of 19 years; they were actually aged 19 years or older.
References
Caroline W Cohen, Kevin R Fontaine, Rebecca C Arend, Ronald D Alvarez, Charles A Leath III, Warner K Huh, Kerri S Bevis, Kenneth H Kim, John M Straughn, Barbara A Gower; A Ketogenic Diet Reduces Central Obesity and Serum Insulin in Women with Ovarian or Endometrial Cancer, The Journal of Nutrition, Volume 148, Issue 8, 1 August 2018, Pages 1253–1260, https://doi.org/10.1093/jn/nxy119
Ketosis and the Ketogenic Diet Explained – A Complete Beginners Guide. Bulletproof blog website https://blog.bulletproof.com/keto-diet-guide/. Accessed August 20, 2018.