Expert's opinion
Breast cancer is one of the most common cancer diagnoses worldwide, with over 2 million new cases[1] yearly. This significant health burden has called the scientific community to action to find alternative and complementary breast cancer treatments.
Different types of breast cancer are classified based on where in the breast the cancer originated, how much the cancer has grown, and how the cancer behaves. Estrogen-positive breast cancer is a specific type of cancer with cancer cells with receptors for the hormone estrogen on their surface. This means estrogen levels fuel the growth of the cancer cells.
So, what is the link between the keto diet and estrogen-positive breast cancer? Well, diet as an adjunctive therapy for breast cancer treatment[2] has been an essential topic of discussion. Recently, high-fat, low-carb diets such as the ketogenic diet have gained popularity. Research has taken place to help determine if the keto diet is an effective adjunct in treating cancer.
In this article, we will discuss the ketogenic diet, how it can be used to treat estrogen-positive breast cancer, and the proposed scientific mechanisms behind why it might work for breast cancer patients. We will also dive into the recent and future research around this topic.
Keto Diet And Estrogen Positive Breast Cancer
Estrogen-positive breast cancer is the most common form of breast cancer, accounting for approximately 80% of all cases.[2] In recent years, there has been an increasing interest in the potential role of ketogenic diets in managing breast cancer and reducing cancer risk.
Increasing research[3] has demonstrated that there may be many benefits to implementing the ketogenic diet along with traditional breast cancer treatment, including slowing the growth of tumor cells, reducing inflammation, altering cancer cell metabolism, and potentiating the effects of standard therapies.
Keto Diet For Cancer Treatment
Ketogenic metabolic therapy[4] is a novel approach to cancer treatment that involves using a ketogenic diet to target the metabolic characteristics of cancer cells. The main aim of this therapy is to gradually degrade and eliminate tumor cells without causing toxicity to healthy cells.
The ketogenic diet appears to sensitize most cancers to standard therapy, such as chemotherapy and radiation, by targeting the reprogrammed metabolism of cancer cells. This makes the ketogenic diet a promising candidate for adjuvant therapy to cancer treatment.
The macronutrient composition of the ketogenic diet forces the body to metabolize fats rather than carbohydrates or proteins and shifts the body’s primary energy substrate from glucose to ketones. The Warburg effect[5] is believed to occur when cancer cells rewire their metabolism to promote growth, survival, proliferation, and long-term maintenance.
Cancer cells are thought to rely on glycolysis to fuel their growth, even in the presence of oxygen. This theory supports the hypothesis that cancer cell growth will be hampered by a shift to ketone metabolism[6] through the use of the ketogenic diet.
Research on the potential benefits of ketogenic metabolic therapy for cancer is still in its early stages, with most studies being conducted in animal models or small groups of late-stage cancer patients. A recent literature review[7] found that approximately 90% of the studies they reviewed demonstrated that carbohydrate restriction was protective against cancer, with only one study on colorectal cancer demonstrating tumor growth continued.
Other preliminary findings have also been promising, with reported benefits including slowed tumor growth,[7] protection of healthy cells from damage[6] caused by chemotherapy or radiation, enhancement of the effectiveness of anticancer drugs,[8] and improved quality of life for patients.
The ketogenic diet should be implemented under the guidance of your doctor or nutritionist. There are even keto diet apps that can help you stick to your plan, as there has been conflicting evidence showing cancer patients have difficulty[9] implementing the diet.
The Ketogenic Diet: An Overview
The ketogenic diet is a high-fat, low-carbohydrate, and moderate-protein dietary approach. It has gained popularity recently for its reported weight loss and health benefits.[10]
The keto diet meal plan includes no more than 10% of their calories from carbohydrates, around 20% from protein, and 70% from healthy fats. When the body is deprived of carbohydrates, it switches to burning fat for fuel instead of carbohydrates, a process called ketosis.
Ketosis leads to the production of ketone bodies derived from fatty acids and can be used as an alternative energy source for the body and brain. The primary goal of a ketogenic diet is to achieve and maintain a state of nutritional ketosis, which has been shown to result in lower blood glucose levels, higher ketone body levels, and improved glycemic control.[3]
The ketogenic diet has many potential benefits for cancer patients. Studies[11] have shown that the keto diet lowers the level of insulin and glucose in the blood, which are necessary for tumor growth, potentially slowing or stopping tumor progression. Research[12] has also demonstrated that some cancer cells are less able to metabolize ketones compared with healthy cells, which may also halt tumor growth.
Cancer can lead to unwanted weight and muscle loss, decreased quality of life, and reduced physical performance. Research[13] has shown that the ketogenic diet can improve body composition (muscle/fat ratio), physical performance, and quality of life in cancer patients. For these reasons, the keto diet has emerged as a possible adjuvant treatment option for various cancers, including breast cancer.
The best way to get into ketosis is by implementing the diet, but there are also supplements on the market that may help. Before beginning any nutritional therapy, it is best to meet with a nutritionist to discuss the pros and cons of the keto diet.
Possible Breast Cancer Prevention Mechanisms Via Keto Diet
Target Mitochondrial Metabolism Of Breast Cancer Cells
The initiating agents for cancer development can be anything that disrupts mitochondrial energy metabolism. Chemicals, x-rays, viruses, diet, and lifestyle choices can all impair mitochondrial energy production.
Mitochondria are the powerhouses of the cell. They create the energy we need to survive, called adenosine triphosphate (ATP). Cancer cells have been shown to demonstrate dysfunctional metabolism, which increases reactive oxygen species.
Through a ketogenic diet, cancer cells are forced to use mitochondrial oxidative metabolism,[14] which selectively causes metabolic oxidative stress[15] in cancer versus normal cells. Research[16] has shown that increased metabolic oxidative stress in cancer cells may put these cells in a weakened state and, in turn, can selectively sensitize cancer cells to conventional radiation and chemotherapies.
Targeting Glucose Metabolism Of Breast Cancer Cells
Some studies[16] have suggested that a ketogenic diet may help reduce cancer risk by affecting tumor cells and their metabolism. Cancer cells have been shown to have a higher reliance on glucose[17] for energy, and a ketogenic diet, by reducing glucose levels in the blood, may potentially starve the tumor cells of their preferred fuel source. This has led to the hypothesis that a ketogenic diet may have a role in adjuvant cancer therapy and prevent cancer cell proliferation.
Additionally, reducing insulin resistance and improving body composition associated with a ketogenic diet may contribute to a lower breast cancer risk, as obesity is a significant risk factor.[18]
Reducing Inflammation
In addition, ketogenic diets have been found to have anti-inflammatory effects, which may help reduce inflammation-driven cancer development and progression. Recent research[11] has shown that the ketogenic diet decreases TNF-alpha and increases IL-10. These two immune mediators play an essential role in the homeostasis and regulation of inflammation in the body and assist with stopping the inflammatory processes.
Research[19] has shown that elevated production of TNF-alpha contributes to an overwhelming inflammatory response and tissue damage, while IL-10 suppresses the production of numerous activating and regulatory mediators. Upregulation of these mediators through the ketogenic diet can contribute to decreased inflammation and potential improvement in immune system regulation.
Keto Diet And Breast Cancer Trials
No major cancer health organizations currently recommend the ketogenic diet for cancer treatment or cancer prevention. Although the existing research shows promising potential benefits of a ketogenic diet for breast cancer patients, it is still in its early stages, and more extensive studies are needed to determine its safety, efficacy, and long-term effects.
Future research should focus on identifying specific patient populations that may benefit from a ketogenic diet and developing individualized dietary plans that consider the unique needs and preferences of breast cancer patients.
Currently, clinical trials are taking place to explore further the role of the ketogenic diet in estrogen-positive breast cancer in people with obesity and those with recurrent breast cancer. In one clinical trial, researchers will evaluate the feasibility and tolerability of a 2-week ketogenic diet combined with targeted endocrine therapy before surgery for early-stage estrogen-positive breast cancer. The findings of these clinical trials will help patients make more informed decisions regarding if this adjunctive treatment is right for them.
In the meantime, patients interested in trying a ketogenic diet should consult with their healthcare providers and work closely with a dietitian trained in ketogenic diets to ensure this is a safe and effective dietary intervention.
Conclusion
In summary, the current state of research on ketogenic diets and their potential impact on estrogen-positive breast cancer patients is still in its infancy. Although some studies indicate potential benefits like slowed tumor growth and improved response to conventional treatments, more extensive research is required to fully understand the ketogenic diet’s role in treating breast cancer and reducing cancer risk.
Breast cancer patients considering a ketogenic diet should consult their healthcare providers and work closely with a trained dietitian to ensure a safe and effective dietary intervention. As our understanding of the relationship between diet and cancer grows, we must remain informed and open to new findings and approaches that may help improve the lives of those affected by this disease.
Frequently Asked Questions
Research has shown that the use of the keto diet in conjunction with standard cancer therapies may slow the progression of breast cancer in specific populations.
Research[6] has demonstrated that the ketogenic diet may prevent cancer cachexia by altering the metabolic pathways of cancer cells.
There are numerous hypotheses on the mechanisms behind how the ketogenic diet complements traditional breast cancer treatment. The most common theories include altering blood glucose levels, changing mitochondrial metabolism, and reducing inflammation, among other theories.
