Potential Benefits of the Keto Diet for Individuals with Breast Cancer

It is estimated that approximately 2.3 million women worldwide were diagnosed with breast cancer in 2020.⁽¹⁾ Factors such as age, gender, and family history are known to contribute to this type of cancer. Studies have also indicated a potential link between unhealthy dietary habits and an increased risk of breast cancer. Conversely, adopting healthy dietary patterns has shown promise in reducing breast cancer recurrence and overall mortality in survivors.^(2,3,4,5)

A recent review published in the journal Nutrients by researchers at the University of Catania in Italy suggests that embracing a ketogenic (keto) diet could offer therapeutic advantages for individuals dealing with breast cancer.⁽⁶⁾

Over time, scientific investigations have delved into the manifold ways in which diet can impact breast cancer.

Unhealthy dietary patterns have been correlated with an increased risk of breast cancer, as evidenced by recent research. For instance, a study released in September 2023 identified a connection between consuming ultra-processed foods and heightened breast cancer risk. Additionally, elevated sugar intake, notably through the consumption of sugar-sweetened sodas, has shown associations with an elevated risk for breast cancer.^(7,8,9)

On the other hand, studies have highlighted the potential positive impact of sound nutritional practices on breast cancer prevention and treatment. A study published in May 2021 demonstrated that a diet rich in fruits, vegetables, cheese, and soy products, coupled with reduced intake of red and processed meats, was linked to a decreased risk of breast cancer.⁽¹⁰⁾

Another study, from April 2023, indicated that adherence to the Mediterranean diet potentially exerted a protective effect against breast cancer. Moreover, findings from a study in November 2021 suggested that the dietary choices of individuals with breast cancer might alleviate treatment-related toxicities and enhance prognosis.^(11,12)

The ketogenic, or “keto,” diet is characterized by a predominant intake of calories from proteins and healthy fats, while restricting the consumption of carbohydrates. In the standard keto diet, individuals typically derive only five to ten percent of their daily calorie intake from carbohydrates. By cutting down on their intake of carbohydrates, the body shifts to burning fat for energy, inducing a metabolic state known as ketosis. 

Research suggests several potential benefits associated with adhering to a keto diet. These include aiding weight loss, curbing appetite, and promoting cardiovascular health. Moreover, the keto diet has exhibited promise in managing certain health conditions such as type 2 diabetes, epilepsy, Alzheimer’s disease, polycystic ovary syndrome (PCOS), and cancer.^{(13,14,15,16)}

However, the keto diet does come with certain drawbacks. Individuals initiating this diet might experience a transitional phase known as the “keto flu” as their bodies adjust from carb to fat metabolism.⁽¹⁷⁾ Long-term adherence to the keto diet could lead to side effects such as kidney stones, vitamin deficiencies, liver issues, and low protein levels in the blood (hypoproteinemia).⁽¹⁸⁾

Moreover, specific populations, including individuals with gallbladder, pancreas, liver, or thyroid conditions, pregnant individuals, and those with eating disorders, are advised against following the keto diet due to potential risks and complications. 

In their recent review, researchers conducted an extensive analysis of available evidence regarding the potential correlation between the ketogenic (keto) diet and breast cancer. Their assessment involved a thorough examination of preclinical and clinical studies exploring this relationship. 

Upon looking at the gathered data, the scientists revealed a spectrum of findings within existing studies. Some suggest that adopting a keto diet might exhibit potential benefits by impeding tumor growth and also improving the treatment response in cases of breast cancer.^(19,20) 

However, the researchers further emphasized that there was a need for carrying out further clinical trials to substantiate these potential positive effects. Currently, the findings remain inconclusive, largely due to limited human trial data, prompting the need for more comprehensive studies. 

Furthermore, the scientists highlighted concerns regarding the safety and long-term implications of sustained ketosis specifically in cancer patients, underscoring the need for a more comprehensive understanding of the diet’s effects in this context.⁽²¹⁾ 

Despite some potentially promising findings, experts have cautioned against viewing the ketogenic (keto) diet as a preventive or curative measure for breast cancer. 

According so some oncologists, the preliminary nature of current research does not allow doctors to immediately advocate the keto diet for individuals diagnosed with cancer. 

It is important that there are several ongoing clinical trials that are looking to carefully compare the effects of ketogenic diets versus normal healthy diets in cancer patients. These trials may offer better insights into the potential benefits, if any, and the extent of such benefits in relation to breast cancer therapy. It is, therefore, necessary that the scientific community waits for the completion and publication of these clinical trials before considering dietary recommendations for patients. 

It is important to understand that the keto diet is not universally suitable for everyone, especially for all individuals undergoing breast cancer treatment. In fact, there can even be certain potential drawbacks for cancer patients following this kind of a restrictive diet. 

It is very much possible that following a restricted diet, such as the keto diet, becomes burdensome and causes increased levels of stress or a decline in a patient’s quality of life during their cancer treatment. In such a scenario, a reevaluation of the dietary approach is must. One also needs to be guarded about any significant weight loss and malnutrition during cancer treatment. This is very much a possibility in cases where there are restrictions imposed on a patient’s diet, resulting in these issues. In such cases, the benefits of a keto diet for a breast cancer patient will soon get cancelled out. 

Furthermore, extreme diets like the keto diet, which severely limit or exclude certain food groups, could also potentially lead to deficiencies and create a pro-inflammatory environment, which is contrary to the intended goals of cancer management. 

It is, therefore, important to evaluate any dietary regimen in conjunction with ongoing medical treatments like chemotherapy, radiation, and targeted therapies. One must look at the necessity of preserving the patient’s muscle mass, strength, and overall well-being while undergoing medical interventions. This is why doctors and nutritionists advise patients to consult healthcare professionals before making any kind of significant changes to their diet, including adopting extreme measures like the keto diet. 

While the results of the clinical trials on keto diet are awaited, here are some other dietary tips that can be beneficial for individuals undergoing treatment for breast cancer: 

• Focus on Balanced Nutrition: Emphasize a balanced diet rich in fruits, vegetables, whole grains, lean proteins (such as poultry, fish, beans, and nuts), and healthy fats (like olive oil and avocados). 
• Remain Hydrated: Encourage adequate hydration by drinking plenty of water and avoiding excessive consumption of sugary or caffeinated beverages.
• Limit your intake of Processed Foods: Reduce the intake of processed foods, sugary snacks, and high-fat foods. Opt for whole, unprocessed foods whenever possible.
• Opt for Moderate Portions: Encourage portion control to manage weight and prevent excessive calorie intake, which can be essential during treatment and recovery.
• Maintain your Protein Intake: Ensure adequate protein intake to support healing and preserve muscle mass. Sources like lean meats, fish, eggs, dairy, legumes, and tofu can be beneficial.
• Include Antioxidants: Encourage foods rich in antioxidants, such as berries, citrus fruits, leafy greens, and cruciferous vegetables like broccoli and cabbage. These can help combat oxidative stress.
• Include Omega-3 Fatty Acids: Incorporate foods rich in omega-3 fatty acids, such as fatty fish (salmon, mackerel), flaxseeds, chia seeds, and walnuts. These can help reduce inflammation.
• Focus on getting Calcium and Vitamin D: Ensure adequate intake of calcium and vitamin D through sources like dairy, fortified foods, leafy greens, and supplements if recommended by a healthcare professional. They support bone health, especially if undergoing certain cancer treatments.
• Manage Digestive Issues: Address any digestive issues or discomfort by incorporating easily digestible foods like soups, cooked vegetables, and smaller, frequent meals.
• Consult a Registered Dietitian: Encourage consultation with a registered dietitian specializing in oncology. They can provide personalized dietary recommendations tailored to the individual’s specific needs and treatment plan.

Remember, individual responses to food during cancer treatment vary. This is why it is crucial to consider personal preferences and tolerances. Always consult with healthcare professionals, including oncologists and dietitians, for guidance tailored to the individual’s health status and treatment plan. 

While preliminary research suggests some potential benefits of the ketogenic (keto) diet for individuals with breast cancer, these findings are not yet conclusive. Some studies indicate a possible link between the keto diet and inhibiting tumor growth or improving treatment response. However, there is a need for more extensive and rigorous clinical trials to validate these findings and determine the degree of benefit, if any, that the keto diet may offer. 

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