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Diet in cancer

Dr. troph. Gisela Krause-Fabricius

No tumor can be defeated with diet alone. However, researchers have found that a diet that is low in carbohydrates and extremely high in fat can contribute to this Cancer cell growth to inhibit.

According to diseases of the cardiovascular system is cancer the second most common diagnosis in Germany. According to the Robert Koch Institute, around 450,000 people will develop cancer in this country in 2010. But cancer is not a homogeneous disease in itself. To date, over 200 different types of cancer are known, which differ, for example, in the organs or cell structures affected and therefore can have completely different effects on the organism. The complaints that emanate from them are just as different.
However, all malignant (malignant) tumors have one thing in common: In contrast to healthy body cells, they are immortal. While cells normally build up and break down in a controlled manner, tumor cells are not subject to the programmed cell death (apoptosis) with which healthy tissue rejects diseased cells. Tumor cells can multiply unhindered and spread their destructive genetic defect. Unlike healthy cells, they can even penetrate neighboring tissue and smuggle daughter cells (metastases) into other organs via the bloodstream. All of this happens at the expense of the body, because the tumor cells change the metabolism in their favor to promote their growth. They form messenger substances such as cytokines and thus accelerate the breakdown of proteins in the body. This can be twice as high as in healthy people and is mainly at the expense of muscle protein (wasting). In addition, the breakdown of body fat increases and the utilization of glucose is significantly reduced due to an insulin resistance induced by the tumor.

Enable good nutritional status

At the same time, the patients also suffer from a loss of appetite and changes in taste due to various tumor-specific messenger substances. The often very serious side effects of the various cancer therapies can have a further negative impact on the nutritional status. In addition to pain, the most feared consequences of cancer are therefore the tumor-related loss of appetite (anorexia) and the emaciation resulting from it (cachexia). After sepsis (infection with failure of the immune system), cachexia is the second most common cause of cancer death, and in 10-20 percent it is the only cause. An important goal of nutritional therapy in oncological patients is therefore to maintain or regain a good nutritional status and thus to improve tolerance to therapies, to reduce diet-related side effects, to reduce the risk of infection and, as a last but equally important reason: to improve the quality of life improve.

This post is in UGB FORUM with the main topic
Active against cancer

Patients' fear of the disease and the desire to do something themselves often lead to dubious “cancer diets” that are supposed to starve, destroy or cure cancer. Many of these diets are harmful to health because they weaken the already weakened organism or cause deficiency symptoms and undersupply. At best, they are insufficient or poorly adapted to individual needs. It is known that, on the one hand, a good nutritional status significantly improves the prognosis and, on the other hand, a deficiency can lead to the discontinuation of necessary therapies. Unfortunately, little or no attention was paid to this knowledge for a long time: “Eat what you want” or “Eat as before”, were the general recommendations. With better knowledge of tumor metabolism and its influence on the organism, more effective recommendations can be made today: The best possible diet for cancer patients should be high in energy, fat and protein and at the same time rather low in carbohydrates (see table).

Ketogenic diet: carbohydrates play a special role

Carbohydrates, especially glucose, play a major role in the metabolism of oncological patients and tumor cells. Until recently, it was assumed that sugar solutions such as maltodextrin or foods and drinks fortified with sugar were a very good source of energy for patients. Today it is known that the muscles and liver do not use the glucose sufficiently and that the tissues cannot build up adequate glycogen stores. The urgently needed energy is wasted, so to speak. In contrast, the muscle cells can absorb fatty acids, store them or use them for energy production much better than is the case with healthy people. The protein metabolism and requirement also change. Since the protein turnover rate is greatly increased by tumors, the protein requirement increases to approx. 1.2-1.5 g / kg body weight.

Tumor cells like glucose

It is not only the metabolism of the body's own tissues that is changed and has an influence on the demand. The tumor itself also has a metabolism that differs from that of a healthy cell. Malignant cells consume glucose for energy production like healthy cells, but unlike these, most tumor cells “ferment” the sugar. This means that they metabolize it with almost no oxygen (anaerobic glycolysis), even when oxygen is available. The energy yield is 15 times less than with normal oxidation, but the tumor cells compensate for this with a 20-30 times higher intake of glucose, regardless of the food supply. The end product of this anaerobic glycolysis is lactate, which also has protective functions for the tumor cells. In contrast, fats and their building blocks, the fatty acids, are as good as not used by tumor cells, while the consumption of protein is increased many times over.

Ketogenic Diet as Therapy?

This metabolic abnormality of "fermentation" was already described in 1924 by the Nobel Prize winner Otto Heinrich Warburg. The findings are the basis for the theory of the ketogenic diet. In the case of an extremely high-fat, low-carbohydrate diet, ketone bodies are formed which, in high concentrations, reduce the glucose uptake and utilization of the malignant cells and thereby cause them to die. This observation is all the more important because the more aggressive tumors become, use more and more glucose as the only possible source of energy. That is, an obstruction to the breakdown of glucose can inhibit tumor growth. At the same time, the ketone bodies prevent protein breakdown and thus the dreaded muscle wasting. Due to the extremely low-carbohydrate diet, there are also no insulin spikes - insulin and the related insulin-like growth factor (IGF1) are considered to promote the growth of tumor cells. Fats or fatty acids can also counteract inflammatory reactions: Omega-3 fatty acids or their plant relatives, alpha-linolenic acid, have a high anti-inflammatory potential.

Recommendations for nutrient intake in cancer patients:

Fatsat least 50% of the non-protein calories- preferably linseed oil and fish (oil)
(Omega-3 fatty acids approx. 4-6 g)
- butter, coconut fat
- medium chain triglycerides (MCT)
rather not:
- Oils rich in linoleic acid (sunflower, corn germ, soybean oil)
For oleic acid (olive oil) there are currently no consistent results except for prevention. A slight inhibitory effect on tumor growth is assumed, however.
proteinat least 1.2-1.4 g / kg body weight (up to 2 g / kg body weight)animal / vegetable
carbohydratesless than 50% of the total energy consumptionpreferably long-chain carbohydrates or low glycemic index, e.g. B. Whole grain products, vegetables
energy30-35 kcal / kg body weightCancer patients should try to maintain their weight.

High-quality fats play a special role in the diet of cancer patients

"Metabolically adapted nutrition" according to Holm 2007

No long-term studies on "cancer diets" yet

Based on these findings, radically low-carbohydrate, so-called ketogenic diets are propagated to fight cancer. Approx. 10 grams of carbohydrates per 1000 kcal are allowed, at the same time 70-75 percent of the calories should be consumed as fat, of which 20-30 percent as medium-chain fats (MCT) and approx. 0.5-1 g eicosapentaenoic acid (EPA) - an omega-3 fatty acid. Protein intake is said to make up 21 percent of calories. Some successes have already been achieved in vitro and in animal experiments. A study with breast cancer patients was carried out at the University of Würzburg. Individual observations of tumor patients give cause for hope, according to the researchers, that this type of diet could stop or at least slow down the progression of a tumor. The study will be continued at the University Women's Clinic in Mannheim.
Long-term results of such a ketogenic diet as cancer therapy are not yet available. It is also not yet known whether the changed metabolic situation can lead to interactions with drugs or other therapeutic agents. The researchers at the University of Würzburg therefore advise those patients who would like to try this diet to a three-month observation phase under strict medical supervision. The TKTL1 anti-cancer diet according to Dr. Johannes Coy. His thesis is that the TKTL1 gene in cancer patients influences the energy metabolism of tumor cells and can be counteracted with appropriate nutrition. Scientifically controversial, however, is the question of whether the detection of the gene can actually give an indication of the effectiveness of the diet, which, according to Coy, requires special food and dietary supplements. In a press release from March 2010, the German Cancer Society warns against a ketogenic diet as an anti-cancer diet, as there are no clinical studies aside from animal experiments. Other scientists also regard it as "dishonest and unsound", especially since this diet can only be carried out under strict medical supervision and possible undesirable effects on tumor patients cannot be ruled out.

Adapt nutritional recommendations to patients

The recommendations to eat particularly rich in fat and protein seem to be undisputed today. But what do these findings mean for practice? We don't eat proteins or carbohydrates, we have quark, eggs, meat, potatoes or bread on our plates. Taste preferences, aversions, appetite, mood or social environment determine the choice of food. In oncological patients, the choice of food is also decisively influenced by their individual constitution, such as nausea, changes in smell and taste, loss of appetite or discomfort. Taking these personal likes and dislikes into account is the ultimate goal of nutritional therapy - adapting it to scientific knowledge is the ideal solution for individual advice. Adding linseed oil, butter, cream or MCT fats to all meals in food and drinks, for example, has a caloric advantage and fulfills the requirement for a high-fat diet. In addition, fats and oils can neutralize unpleasant tastes and smells. Snacks between meals such as fruit yoghurt or quark enriched with cream provide the patient with protein and fat. The quality and composition of the fats or fatty acids is very important. Omega-3 fatty acids (in linseed, rapeseed and walnut oil, fatty fish such as mackerel or herring) inhibit tumor growth and improve the nutritional status, while omega-6 fatty acids (e.g. sunflower oil, arachidonic acid in meat) stimulate tumor growth and rather stimulate metastasis.

Supplementary food can compensate for deficits

There are now additional foods for oncological and malnourished patients with a high fat (omega-3 fatty acids) and protein content. The additional foods can be drunk as a snack or mixed into desserts or main courses. They come in a variety of acceptable flavors. They are also available as coffee or salty soup. With a high calorie content, they also have a small volume, so that they are suitable as small snacks even for patients who lack appetite. Most of these additional foods can also be used to enhance normal meals.
If the desired amount of fat, especially fish oil, is not achieved due to loss of appetite or reluctance, fish oil capsules as a dietary supplement can be helpful. However, caution should be exercised with other supplements such as vitamins and minerals, as they are easily overdosed. For example, high doses of antioxidants can reduce the effects of radiation. For oncological patients, there are special combination preparations during therapy, which, however, should not be recommended in general, but only after an individual examination by the doctor or nutritional therapist. There is a special need for fat-soluble vitamins after operations in the gastrointestinal tract and in the case of persistent diarrhea. Here, supplements should be given according to the special requirements. Selenium plays a special role, as it can even reduce the side effects of chemotherapy. The attending physician should determine the level of the dosage.

Conquering cancer with food?

Also noteworthy are the foods known as “nutraceuticals”, which are said to have both cancer-inhibiting and immunomodulating effects. The oncologists Richard Béliveau and Denis Gingras have compiled a series of studies in their book “Cancer cells don't like raspberries” which show that foods such as cabbage, onions, garlic, soy, oily fish, berries, turmeric or green tea can individually or collectively cause cancer cells can fight. It remains to be seen to what extent prevention and therapy overlap here; It is certainly not a mistake to include these foods in nutritional therapy. With all dietary recommendations and possible restrictions, however, the patient's quality of life has priority. If a patient is in the mood for some chocolate, a piece of cake or an ice cream, he should and can eat it with pleasure and pleasure. This caresses the psyche a little, which is just as suffering from the illness and therapy as the body.

Online version of: Krause-Fabricius G. Nutrition in cancer. UGB-Forum special: Active against cancer. S 21-24, 2011
Photo: teressa /