Two important studies show that reducing calorie intake activates the immune system and increases the effectiveness of chemotherapy.
Most drugs used in chemotherapy are very strong cell poisons that can kill cells by preventing them from reproducing. However, several observations made in recent years show that this cytotoxic effect is often not enough to remove all tumor cells: for chemotherapy to be truly effective in the long term, it must also restore anti-cancer immune surveillance by activating blood cells. , specializing in the disposal of foreign bodies.
For example, studies show that by killing cancer cells, some chemotherapeutic drugs (anthracyclines, oxaliplatin) cause a number of events that lead to the production of signals capable of activating the immune response. This phenomenon, called “immunogenic cell death”, can be likened to a vaccine, in which dying cancer cells elicit a strong immune response and allow the complete destruction of residual tumor cells.
Caloric restriction activates immunity
Very encouraging preliminary results suggest that the effectiveness of chemotherapy can be significantly improved by drastically reducing caloric intake. For example, in mice with human tumors, fasting for 48 hours increases survival, with almost half of the animals still alive 180 days after treatment, while all normally fed animals have died.
Two recent major studies by teams of French and American researchers suggest that this positive impact of caloric restriction is due to increased anti-cancer activity in the immune system. For example, it has been observed that the diet developed by Dr. Valtera Longa, which mimics the positive effects of fasting on the body, improves the response of mice with breast tumors and melanomas to chemotherapy by causing a significant increase in killer lymphocytes. . In the same vein, injections of substances that mimic the effects of fasting on metabolism caused a decrease in regulatory T cells (a class of white blood cells that reduce the anti-cancer immune response), which improved lymphocyte activity. killers and led to a significant reduction in the tumor burden.
Eating well means eating less
Team Dr. Longa is working with several hospitals to see if calorie restriction improves patients’ response to chemotherapy, and we should know very soon whether these animal results can be applied to humans. Meanwhile, it is interesting to note that studies show that fasting for up to 72 hours is well tolerated by patients and appears to be associated with a significant reduction in the side effects of chemotherapy. These observations are not so surprising given that our metabolism has evolved to function maximally in conditions of food shortages. In addition, most chronic diseases that currently affect the population, including a large number of cancers, are a direct result of excessive food consumption. Eating well can simply mean eating less.
Lee C et al. Fasting cycles slow tumor growth and sensitize many types of cancer cells to chemotherapy. Sci Transl Med. 2012; 4: 124ra27.
Di Biase S et al. A fasting diet reduces HO-1 and promotes T cell-mediated cytotoxicity of tumors. Cancer Cell 2016; 30: 136-46.
Pietrocola F et al. Caloric restriction mimetics increase anti-cancer immunosurveillance. Cancer Cell 2016; 30: 147-60.
Dorff TB et al. Safety and feasibility of starvation in combination with platinum-based chemotherapy. BMC Cancer 2016; 16: 360.
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