The internet is awash with advice on how to stop or even cure cancer through diet. Separating fact from fiction requires careful consideration of the evidence. While no single diet can eradicate cancer, understanding the relationship between nutrition and cancer risk – both in prevention and support during treatment – is crucial.
Can Diet Stop or Cure Cancer?
To be clear, there is no diet or dietary pattern that can halt or cure cancer in humans. There is no scientific evidence to support the claim that a specific diet can cure cancer or replace conventional cancer treatment.
In recent years, interest in the role of nutrition in cancer has grown. However, many complementary or alternative diets marketed for cancer are highly restrictive and often make unsubstantiated claims. It’s generally not advisable to eliminate entire food groups, such as dairy or carbohydrates, during cancer treatment. Doing so can lead to nutritional deficiencies and impair the ability to maintain weight, potentially jeopardizing the treatment plan.
If a dietary pattern, food, or supplement truly possessed the power to effectively slow or cure cancer, it would be widely adopted in medicine. That is not the case. Cancer is a complex, multifactorial process that cannot be caused or resolved by a single factor.
Does Diet Play a Role in Cancer Development?
Approximately 40–50% of all cancers and cancer deaths are linked to modifiable, preventable risk factors. Significant contributors include smoking (19–30% of cases), excess body weight (7.8%), diet and alcohol consumption (5.6%). Approximately 90–95% of cancers are attributed to environmental and lifestyle factors, with only 5–10% being genetically determined.
Various nutrients can help slow down the development of cancer, and in some cases, even help prevent it. Examples include glucosinolates (found in cruciferous vegetables), green tea, coffee, a variety of fruits and vegetables, selenium, and vitamin D3.
Conversely, some dietary components can promote cancer development. Polycyclic aromatic hydrocarbons and heterocyclic amines, formed when protein-rich foods are charred, are examples.
It’s important to remember that the effects of these nutrients should be considered within a preventative context, not as a treatment for existing cancer.
What About ‘Alternative Cancer Diets’? Is There Any Truth to Them?
Several ‘alternative’ cancer diets frequently surface, including the ketogenic diet, the alkaline diet, and intermittent fasting. Let’s examine each.
Does the Ketogenic Diet Help with Cancer?
The ketogenic diet may create an unfavorable metabolic environment for cancer cells and could be considered an adjunctive strategy within a patient-specific, multifactorial therapy. Most preclinical studies and several clinical trials suggest benefits of the ketogenic diet in combination with standard therapies, potentially enhancing the antitumor effects of conventional chemotherapy and radiotherapy. The diet is generally well-tolerated and may contribute to a better quality of life.
However, it’s crucial to emphasize that no leading cancer organization recommends the ketogenic diet as a sole treatment for cancer patients, nor is it recommended for cancer prevention.
Does the Alkaline Diet Help with Cancer?
The acidity or alkalinity of the body is measured by the pH scale, which is tightly regulated by the kidneys and lungs. A pH of 0 is strongly acidic, a pH of 14 is strongly alkaline, and a pH of 7 is neutral. Different parts of the body have specific pH levels to optimize their functions. Blood is naturally slightly alkaline (around pH 7.4), while the stomach is highly acidic (between pH 1.5 and 3.5) to aid digestion. It is not possible to change the pH of the blood through diet.
The alkaline diet is based on the idea that an acidic environment in the body promotes diseases like cancer, while an alkaline environment supports good health. This diet has gained popularity in the media, but studies reporting such results have been conducted in laboratory settings and are not directly applicable to the human body.
There is no scientific evidence that an alkaline diet reduces cancer risk or provides protection against cancer. Such a diet, often avoiding meat and dairy, does not alter the pH of the blood or other organs. A restrictive diet can lead to unwanted weight loss and deficiencies in essential nutrients like calcium, vitamin D3, vitamin B12, and protein, impacting health and treatment.
Even if a diet could theoretically alter blood pH, a strongly alkaline environment could actually reduce the effectiveness of chemotherapy.
Does Intermittent Fasting Help with Cancer?
Intermittent fasting involves periods of fasting or severely restricted eating. This type of diet is generally not recommended for individuals diagnosed with cancer. Fasting can reduce the body’s ability to absorb essential nutrients. During cancer treatment, the body requires ample energy, protein, vitamins, and minerals to withstand the therapy. Fasting also increases the risk of weight loss. Maintaining weight is important during cancer treatment, even for those who are overweight.
Research on intermittent fasting is still in its early stages, primarily conducted on animals and isolated cells. There is limited evidence to support its use. Fasting is not recommended for patients at risk of malnutrition or those with diabetes.
What Should a Cancer Patient Eat and Drink?
A nutritious diet is essential during cancer treatment. Research shows that weight loss due to cancer or treatment can reduce the response to therapy, worsen side effects, and decrease overall survival. Unintentional weight loss is also stressful and can significantly impact quality of life.
A healthy diet includes a variety of foods, including carbohydrates, proteins, fats, vitamins, and minerals. Dietary patterns rich in energy and protein help patients maintain a healthy weight during treatment. However, side effects of the disease or therapy can make eating and maintaining weight difficult.
A helpful publication from UZ Gent, titled ‘Voeding bij Kanker’ (Nutrition in Cancer), provides practical and accessible information on how to approach nutrition during cancer treatment.
What is Your Advice Regarding Diet and Cancer?
There is no diet, superfood, vitamin, or beverage that can cure cancer. Cancer typically arises from years of genetic damage to cells, caused by environmental factors like pollution and lifestyle choices, and to a lesser extent, genetic predisposition. Once cancer is diagnosed, no amount of kale or vitamins will make the disease disappear.
My advice regarding cancer is clear: focus on prevention, where nutrition plays a vital role, and if you have cancer, trust in conventional medicine and the well-established treatments currently available. In recent years, cancer treatment techniques have improved dramatically, significantly increasing the chances of cure with early detection. Substantial investment is also being made in this area, as demonstrated by the efforts of organizations like ‘Kom op tegen Kanker’ and ‘Stichting tegen Kanker’, which invest millions of euros annually in scientific research.
Do not rely on dubious diets or quacks offering various supplements, pills, or ointments. There is no scientific evidence that these remedies actually help. Relying on them is very risky: there is no guarantee of improvement or cure, and you risk missing out on valuable, proven treatments from conventional medicine.
