Free radicals also inhibit cancer tumor growth
Free radicals have always been considered a risk factor for the development of cancer. However, David Tuveson of the Cancer Research Institute in Cambridge and colleagues have shown in a comprehensive study with mice that free radicals reduce the growth of certain types of cancer instead of increasing the risk of cancer. The intake of antioxidants through food, previously classified as cancer-preventive, could possibly even increase the risk of cancer.
Not least because of the relatively high content of antioxidants in the form of vitamins and trace elements, the consumption of fruits and vegetables is attributed to a cancer preventive effect. Because the antioxidants absorb the free radicals in our body and thus prevent them from causing further damage. So far, free radicals have been considered an essential risk factor for the development of tumors and the occurrence of other diseases, such as Parkinson's or arteriosclerosis. But researchers at the Cancer Research Institute in Cambridge have now found that free radicals can inhibit the development of tumors in certain types of cancer and thus reduce the risk of cancer. This at least puts the positive effects of the antioxidants in relation to cancer prevention at risk.
Free radicals previously known to be harmful to health Contrary to previous scientific knowledge, the researchers at the Cancer Research Institute came to the conclusion in their current study that free radicals do not necessarily increase the risk of cancer, but can definitely inhibit the growth of tumors. The free radicals, also known as reactive oxygen species (ROS), are continuously formed in the human body as intermediate products of the metabolism in the mitochondria (tiny cell power plants). Tobacco smoking, UV radiation and ionizing radiation also contribute to the formation of free radicals in the body. In their molecular structure, the free radicals are characterized by the fact that they have at least one unpaired electron on their outer electron shell. In order to compensate for the electron deficit, the electrons of other molecules in the organism are bound, as a result of which these molecules in turn become free radicals and in turn bind electrons of other molecules. As a result, components of the cell membrane, for example, can be broken up in a regular chain reaction and permanently damaged, the researchers report. Since electrons from proteins or, in the worst case, DNA, can also be bound by the free radicals, long-term health risks are at risk.
Reactive oxygen species block tumor growth The human organism uses antioxidants to fight free radicals. The antioxidants are part of a sophisticated defense system that the body uses to prevent the chain reactions of free radicals. As so-called radical scavengers, the antioxidants such as vitamin A, vitamin C, vitamin E, certain flavonoids and other trace elements stabilize the free radicals and thus prevent them from reacting with other molecules in the organism. The free radicals are then excreted from the body before they can start their chain reaction. The antioxidants are therefore considered to be of major importance for health and, for example, if there is too little antioxidant available due to a vitamin C deficiency, the body's defense mechanism threatens to collapse against free radicals. According to the current state of research, cell damage and serious health impairments can result. But David Tuveson from the Cancer Research Institute in Cambridge and colleagues have now found that the free radicals in the body can also have a positive effect. The scientists found that the reactive oxygen species can block the growth of tumors in the pancreas.
Cancer cells don't like free radicals In their studies on mice, the researchers at the Cancer Research Institute were able to show “that cancer cells don't like reactive oxygen species,” explained David Tuveson. Due to an increased concentration of free radicals, the cancer cells in the pancreas of the mice have died, Tuveson continues. In the animals, the antioxidant defense system had already become active at the beginning of cancer growth and, with the help of protein Nrf2, initiated the binding of the reactive oxygen species (ROS), explained Tuveson and colleagues. If the protein Nrf2 was missing, the growth of the cancer cells was blocked by the high ROS values and only after antioxidants were added, the tumor continued to grow, the researchers of the Cancer Research Institute report.
Do antioxidants increase cancer risk? This suggests that, contrary to all previous knowledge, antioxidants could certainly increase the risk of cancer. However, according to the British researchers, the situation is not that simple. Her study by no means shows that the antioxidants have a generally cancer-promoting effect and should not be misunderstood as an appeal that "people should eat unhealthy food," emphasized David Tuveson and colleagues. Because overall the positive health effects of the antioxidants clearly outweigh. According to the experts, these also have a cell-protecting and anti-inflammatory function, the importance of which for health should not be underestimated. Tuveson explained that the current findings do not speak against fruit and vegetable consumption, but rather the interesting question is how the antioxidant protective system of cancer cells can be switched off. Because if this mechanism could be switched off, the cancer cells would be exposed to the attacks of free radicals without protection, which would open up opportunities for new treatment approaches and treatment methods, explained Tuveson.
The positive effects of the antioxidants on health The consumption of antioxidants can still be recommended due to the various positive health effects regardless of the current study results, the British researchers said. Antioxidants are also considered an essential part of the diet in natural medicine, not least because of their cell-protecting and anti-inflammatory effects. For example, onions, turmeric and cranberries have always been used as “natural antibiotics” in naturopathic treatments due to their high antioxidant content. Broccoli, ginger, coffee, garlic, mangoes, parsley, asparagus, tea, tomatoes, whole grain rice and grapes are other types of fruit and vegetables, which are believed to have a positive health effect due to their high natural antioxidant content. (fp)
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