London: It`s now scientifically proved -- stress really does make one`s hair go grey.
A study by Duke University has found that when the going gets tough, chemicals are triggered which damage DNA and leads people to look older and also increases the risk of diseases.
In fact, researchers have based their findings on an analysis of mice who were given an adrenalin-like compound to trigger stress; the subjects had reduced amounts of a protein that keeps people healthy by protecting cells from developing abnormalities, `The Daily Telegraph` reported.
Prof Robert Lefkowitz, who led the study, said: "This could give us a plausible explanation of how chronic stress may lead to a variety of human conditions and disorders, which range from merely cosmetic, like greying hair, to life- threatening disorders like malignancies."
In experiments the researchers discovered a molecular mechanism through which adrenaline acted to destroy DNA.
Over four weeks the mice were injected with the compound which led to degradation of the protein called p53 -- dubbed the "guardian of the genome" for its role in preventing cancer -- which was present in lower levels over time.
Prof Lefkowitz said: "We believe this paper is the first to propose a specific mechanism through which a hallmark of chronic stress, elevated adrenaline, could eventually cause DNA damage that is detectable."
The study also showed DNA damage was prevented in mice lacking a protein known as beta-arrestin 1. Loss of it stabilised levels of p53 both in the thymus, an organ that strongly responds to acute or chronic stress, and in testes where paternal stress might affect an offspring`s genome.
Co-researcher Dr Makoto Hara added: "The study showed chronic stress leads to prolonged lowering of p53 levels. We hypothesise this is the reason for the chromosomal irregularities we found in these chronically stressed mice."
The team is now planning future studies in which mice are placed under stress by restraining them to creating their own adrenaline or stress reaction to show if their physical reactions also lead to DNA damage.
The findings have been published in the latest edition of the `Nature` journal.