Ms. Koppold-Liebscher, the positive effects of fasting are increasingly finding new empirical evidence in human studies. Can this also be observed in the field of cancer therapy?
Yes! Just ten to 20 years ago, it was downright frowned upon to bring fasting into the context of cancer therapy. Cancer was therefore generally classified as a contraindication for fasting. However, a lot has happened in recent years.
What exactly has happened in recent years?
The decisive turn was triggered by basic research in the USA. The team led by Professor Valter Longo from the University of California in LA observed that organisms that receive energy or food only irregularly live longer. In animal experiments, they then found that fasting has an effect on metabolic processes that are involved in the development of tumors. Researchers also found that mice that had cancer and were treated with chemotherapy had better outcomes. The tumor regressed more markedly when the animals were placed on food deprivation.
How can these findings be explained?
Fasting means stress for both normal and tumor cells. However, they react differently to it. Fasting makes healthy cells more resistant, which is partly due to the activation of cellular processes such as autophagy. This is the ability to, to a certain extent, recycle old cell components in times of food shortage. Enzymes that are no longer needed or entire cell organelles are broken down into their components and reused. The cells interact less with their environment and are not in growth mode. As a result, the cells have to absorb fewer nutrients from their environment – and so they come into less contact with the chemotherapeutic agents.
And how do tumor cells react to fasting?
Most tumor cells have a significantly lower resistance to stress. Most of the time they cannot slow down their metabolism. Despite the lack of food, they remain in growth mode, keep dividing and multiplying and absorb everything that is available. This includes chemotherapy drugs. It is true that they also absorb this when they are not fasting; however, fasting puts the cells in a state of stress that weakens them. This enhances the effects of the chemotoxic action.
Fasting regulates certain hormones – is this also relevant for fighting tumors?
Yes, the insulin-like growth factor IGF-1 in particular plays a major role in cell growth. A high level of IGF-1 is associated with a higher prevalence of various forms of cancer and it plays a crucial role in tumor growth. Dietary changes such as fasting can down-regulate this hormone.
seit In 2020 you are leading a large study mainly with breast cancer patients. What is special about this study?
On the one hand, the form of fasting. Most studies are conducted using the mock fasting diet developed by Longo. Food is consumed whose energy is not so easy for tumor cells to break down – i.e. a lot of roughage and little protein. In our study, the test persons fasted in the classic way: They took in fewer calories in the form of juices and tea. Fasting is only done before and after chemotherapy treatment. In addition, we are the only working group in the world to have a control group that eats a vegan and low-sugar diet.