A diagnosis of cancer is a difficult time for both patients and their families. It can cause many psychological, physical and spiritual challenges for patients living with the disease.
It is understandable, therefore, to understand the search for help to combat the disease itself or to alleviate the side effects of treatment through diet.
But what types of diets can we find at this point?
– Complementary diet: a diet used in conjunction with medical treatment to treat cancer.
– Alternative diet: a diet used to replace medical treatment for cancer.
There are many myths and incorrect claims supported by pseudoscience that often lead patients to abandon medical treatment and thus put their lives at risk.
The following information summarises some of the most common myths and misconceptions related to diet and cancer.
Dairy
Myth:
– Hormones used in milk production promote the growth of hormone-related cancer tumours.
Fact:
– There is no link between diets containing dairy products and cancer risk or promotion of cancer growth as a result of hormones.
– There is evidence to suggest a protective role of dairy in the development of breast cancer through increased intake of calcium, vitamin D, butyrate, conjugated linoleic acid and lactoferrin.
Soy
Myth:
– Isoflavones, found in soy products, have a chemical structure similar to the hormone estrogen. Estrogen can stimulate some types of cancer, so it was thought that foods containing isoflavones might have the same effect.
Reality:
– Current evidence suggests that a diet containing natural isoflavones is safe.
– Soy foods can be used as part of a healthy, balanced diet as a non-meat source of protein and provide fibre.
Sugar
Myth:
– Sugar feeds cancer cells.
Reality:
– Eliminating sugar from the diet does not restrict glucose (sugar) to cancer cells.
– Sugars are found in a number of healthy foods including complex carbohydrates, fruits and vegetables. These are rich in fibre, vitamins and minerals and have been linked to a lower risk of cancer.
– It is recommended to reduce excess sugar in the diet, particularly in the form of “free sugars” or “simple” sugars, as they are linked to being overweight and are a risk factor for developing cancer.
Alkaline diet
Myth:
– An acidic environment promotes poor health, while an alkaline environment is beneficial and promotes good health. It is claimed that the foods you eat can affect the pH of the body and that as our blood is naturally alkaline (~ pH 7.4) eating acidic foods upsets the balance.
Reality:
– There is no consensus on grouping foods as acidic or alkaline, with many being misclassified.
– Blood pH (7.4) is tightly regulated by the kidneys and respiratory system. Any excess acid is excreted in the urine. Blood pH is not altered by dietary intake.
– This diet suggests that eating alkaline foods can create a hostile environment and therefore kill cancer. However, neither cancer cells nor healthy cells can survive in an alkaline environment.
– There is no scientific evidence establishing the benefit of an alkaline diet in curing cancer.
– The only situation in which blood pH is altered is during metabolic acidosis, when an individual is severely ill.
Ketogenic diet
Myth:
– The ketogenic diet decreases tumour size and spread.
Reality:
– The ketogenic diet is a low-carbohydrate, high-fat diet.
– Existing research is in animals and brain tumours.
– Human data is based on individual cases. Demonstrated weight loss may be a problem in the cancer patient.
– High protein intake may counteract the ketogenic diet by providing glucogenic amino acids for glucose production when the level of protein consumed exceeds normal protein turnover without starvation.
– A ketogenic diet may cause symptoms of constipation, diarrhoea and fatigue.
– Adherence may be low due to palatability and prolonged dietary restrictions.
Fasting
Myth:
– Fasting can improve the effect and symptoms of chemotherapy.
Reality:
– There is some evidence that short-term fasting (STF) may increase the effectiveness and tolerability of chemotherapy, most studies are in early stages or in animals.
– These preliminary studies are based on small groups and mainly in breast and ovarian cancer.
– Fasting regimens have caused side effects including: headaches, hunger, weakness, nausea, dizziness and weight loss.
– Due to lack of strong evidence and risk in certain people, it is not recommended if you have certain conditions, such as heart disease, diabetes, or previous or existing eating disorders. A low body mass index (BMI≤19 kg/m2) or a history of recent weight loss.
Supplements
Myth:
– Complementary alternative medicines can increase survival and reduce recurrence, optimise treatment, alleviate side effects and boost the immune system.
Reality:
– Some vitamins and minerals may interfere with the effectiveness of anti-cancer drugs. High doses of antioxidants (coenzyme Q10, selenium, vitamins A, C, E) can help prevent cell damage, but may prevent chemotherapy from working as efficiently.
– Consult with your oncology team before taking any supplements.
It is essential to tell your oncology doctor and dietitian-nutritionist if you are following a particular diet so they can help you understand and discuss any possible side effects.
Some of these diets can have a detrimental impact on your health and well-being. Some examples are:
– Drug interactions: The diet may interact with your cancer treatment or regular medications.
– Nutritional deficiencies: The diet may be unbalanced and cause nutritional deficiencies.
– Weight and/or muscle loss: The diet may result in unintentional weight loss and loss of muscle mass.
Choosing a complementary diet can have an impact on someone’s health, therefore, it is important to research thoroughly by choosing quality scientific evidence in addition to consulting with your medical-nutritional team.
Source: BDA Oncology.
