Is there a special "anti-carcinogenic" diet for cancer patients?

Author: Sandra Krstev Barać, Master of Nutrition

It is quite clear that nutrition plays an important role in the prevention of cancer, but also during the treatment of oncology patients, as well as in the period after therapy. Cancer patients are often extremely motivated to change their diet and tend to look for a “magic solution” in the form of a special anti-carcinogenic diet. It is estimated that as many as half of patients try one of the diets popular in the media in the hope that such a “special diet” will improve the outcome of treatment and prevent the recurrence of the disease.

The most popular for this purpose are currently the alkaline, paleo and ketogenic diets, veganism and macrobiotics. These dietary patterns certainly offer certain advantages, but an uncritical approach to them can do more harm than good. It is especially dangerous if the patient decides only to go for a “special diet” and reject standard treatment.

It cannot be emphasized enough that an appropriate diet can only be an aid in treatment, not a replacement, and how important it is to consult a nutritionist in order to adapt the diet to the health condition of the oncology patient.

The alkaline diet prefers the so-called “alkaline” foods

The theory behind the alkaline diet is that the cause of cancer lies in the acidic environment in the body, and that this acidosis is created by foods that lower the pH of the blood, such as red meat and poultry, fish and seafood, eggs, processed grains, caffeine and alcohol. In contrast, the goal of the alkaline diet is to raise the pH, which is achieved by making 80% of the diet so-called alkaline foods rich in the minerals calcium, magnesium and potassium, namely vegetables, fruits, nuts, seeds, oils and “traditional” grains such as oats, quinoa, amaranth. In the alkaline diet, the controversial “acidic” foods make up only 20% of the diet.

Despite the fact that the alkaline diet is based on a number of nutrient-rich foods and that even recommendations for cancer prevention emphasize a predominantly plant-based diet, there is no solid scientific evidence in support of the alkaline diet. Additionally, in addition to the fact that following this diet puts you at risk of numerous nutritional deficiencies, it is also possible to have insufficient protein intake, the increased intake of which is otherwise extremely important in the diet of oncology patients. With this in mind, some items of the alkaline diet may be beneficial for patients, but blindly following the diet can make it more difficult for the patient to be treated and recover.

The Paleo diet unfairly neglects the intake of grains and legumes

The Paleolithic diet, or caveman diet, attempts to replicate the dietary pattern of people before the advent of agriculture and technology, when fruits, vegetables, nuts, meat and eggs were consumed, and grains, legumes, dairy products and processed foods in general were not on the menu. Advocates of the Paleo diet claim that humanity has been recording an increase in chronic diseases, including cancer, after the agricultural revolution, when dietary patterns changed.

The claims of paleo diet advocates should be taken with skepticism, especially when we know that grains have been processed and consumed in Europe for over 40,000 years and that people adapt to the diet available to them. In the context of cancer, although there are determinants that may be beneficial for patients, scientific evidence in support of the paleo diet is scarce and the intake of certain foods such as grains and legumes, which play an important role in the diet of oncology patients, is unfairly neglected.

Ketogenic diet as supportive therapy for glioblastoma

The ketogenic diet, which is characterized by a high fat intake (more than 80% of total energy) and extremely limited carbohydrate and protein intake, is the subject of numerous studies in the context of cancer treatment. The thesis is that cancer cells depend on glucose as a source of energy and that ketone bodies that are formed as a result of the ketogenic diet "starve" the cancer, preventing its spread. There is increasing quality evidence that the ketogenic diet can indeed be useful, but only as a supportive therapy to standard oncological treatment and only in certain types of cancer.

The most evidence supports the use of the ketogenic diet in glioblastoma, an aggressive form of brain tumor, which is why more and more oncology centers around the world are incorporating this diet into treatment protocols. However, since the ketogenic diet is not justified for all types of cancer, it is first necessary to screen patients who could potentially benefit from its introduction and create an individual diet plan tailored to the patient. The diet is always carried out in collaboration with an expert who will carefully monitor its safety and success.

Veganism and macrobiotics – nutritionist advice is worth its weight in gold

Veganism is becoming increasingly popular, not only among cancer patients, but also among the entire population. There is increasing knowledge that a vegan diet in childhood can reduce the risk of cancer in adulthood and is now considered a good pledge of health in the future. However, if an oncology patient decides to go vegan with standard therapy, he must be aware of potential deficits – in addition to protein, vegans are critical nutrients omega-3 fatty acids, iron, zinc, iodine, selenium, calcium, vitamin D and especially vitamin B12, so good diet planning with the help of a nutritionist is essential.

Macrobiotics, which basically involves a significant intake of whole grains, to a lesser extent vegetables, legumes and seaweed, and only occasional intake of fruit, white fish, seeds and nuts, has become a very popular supplement in the treatment of cancer. While there is some evidence that macrobiotics can be useful in preventing cancer (especially hormone-dependent cancers), there is a lack of evidence that this dietary pattern is useful in supportive oncology therapy itself. It is important to know that this type of diet can easily lead to insufficient intake of energy, protein, calcium, vitamin D, vitamin B12, iron and zinc, which can negatively affect the outcome of treatment, so it is crucial, in cooperation with a nutritionist, to adjust the diet.

Oncology patients often opt for one of the popular dietary regimes in the media despite limited evidence of their effectiveness and safety. In this way, the patient risks insufficient energy intake, as well as numerous nutritional deficits, which can reduce the possibilities of oncology therapy. If the patient wishes to try one of the popular diets in addition to standard therapy, the only correct way is to consult a nutritionist, so that the diet can be well planned and adapted to the nutritional needs of the cancer patient, and their condition can be regularly monitored in order to recognize and correct any possible malnutrition in a timely manner.

References

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2. Zick SM, Snyder D, Abrams DI. Pros and Cons of Dietary Strategies Popular Among Cancer Patients. Oncology (Williston Park). 2018 ;32(11):542-7.

3. Woolf EC, Scheck AC. The ketogenic diet for the treatment of malignant glioma. J Lipid Res. 2015;56(1):5-10.

4. Vergati M, Krasniqi E, Monte GD, Riondino S, Vallone D, Guadagni F, Ferroni P, Roselli M. Ketogenic Diet and Other Dietary Intervention Strategies in the Treatment of Cancer. Curr Med Chem. 2017;24(12):1170-1185.

5. Weber DD et al. Ketogenic diet in the treatment of cancer – Where do we stand? Mol Metab. 2019 Jul 27. pii: S2212-8778(19)30427-2. [Epub ahead of print]

6. Kushi LH et al. The macrobiotic diet in cancer. J Nutr. 2001;131(11 Suppl):3056S-64S.Rezash V. Can a macrobiotic diet cure cancer? Clin J Oncol Nurs. 2008 Oct;12(5):807-8.

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