“What doesn't kill you, makes you stronger” sings Kelly Clarkson in her 2011 hit. This sentence is not only the trademark of a successful musician and a motivational sentence for many people in everyday life - the sentence also describes a physiological principle very well: the so-called hormesis, which is one of the 8 Hallmarks of Health counts. In this phenomenon, low concentrations of substances that are actually toxic can have a positive effect. This means that certain stimuli train the body and increase its adaptation to these stimuli. The statement "the dose makes the poison" also fits. To better understand the principle of hormesis, let's look at an example. When you start exercising again after a long break, or are just starting out, the first session is often particularly difficult. You might get sore muscles over the next few days from the muscular strain and feel weaker at first. In subsequent exercise sessions, the muscle soreness will be less severe and you will be able to improve your performance. This is because your muscles have become accustomed to the demands of regular training.
Mytohormesis
If we take a closer look at a well-studied hormesis effect, we need to take a look at the processes in the mitochondria In the mitochondria, energy is produced from oxygen and sugar. When the mitochondria have to produce a lot of energy, they also release so-called ROS (which stands for reactive oxygen species, i.e. reactive oxygen species). They act as a signal and warn the cell of stress. It is good if the cell and the body are warned of overexertion and the resulting damage. But as always, the dose makes the poison. Because if too many ROS are released, the body overreacts and the cells are damaged. If the ROS release is only short-term, the body adapts so that it can withstand more in the event of subsequent stress.
This effect becomes noticeable, for example, when you start exercising and the mitochondria in your muscle cells get used to the new demands. Not only does muscle building and the increase in the number of mitochondria begin - the individual mitochondria also become stronger and more efficient.
In order to respond to changing environmental conditions, it is important that the body can adapt through hormesis. This makes your body more adaptable and efficient in the long term and indicates good overall health.
Radiation hormesis
People who are exposed to a certain amount of ionized radiation are less likely to die of cancer. This sounds extremely paradoxical at first. But statistics on radiation workers in England (UK) show that they have a lower cancer mortality rate. It sounds astonishing that radiation, which is actually very harmful, should have a "positive" effect. Researchers are discussing various hypotheses for this, but both this and other studies show the effect of radiation hormesis. Very low doses of ionizing radiation are said to have a protective effect, even in animal experiments. Animals with low doses of radiation showed an approximately 20% higher life expectancy and had a healthier and younger overall appearance even in old age.
Xenohormesis
Let's take a look at the animal and plant world. Everyone wants to survive, but some animals eat plants. As a protective mechanism but also as a stress reaction, some plants then produce toxic substances. Researchers have discovered that these substances can have a life-prolonging effect on some animals in small doses. Because of the interactions between plants and animals, the substances are called xenohormetins. These substances also include Resveratrol, a secondary plant substance that was discovered by Prof. David Sinclair is being researched.
Sources
Literature:
- López-Otín, Carlos, and Guido Kroemer. “Hallmarks of health.”Cell184.1 (2021): 33-63.https://pubmed.ncbi.nlm.nih.gov/33340459/
- Dudley W. Lamming, Jason G. Wood and David A. Sinclair (2005): Small molecules that regulate lifespan: evidence for xenohormesis
Graphics:
The images were purchased under license from Canva.
