London: A broken heart can kill you, says a new study which has found that grief makes people vulnerable to infections from bacteria.

Researchers claim that the emotional stress of losing a loved one can lead to parts of the body's immune system being suppressed, thus in turn weakening one's ability to fight off infections, 'The Sunday Telegraph' reported.

In fact, the researchers from Birmingham University have found that increased stress levels and depression brought on by grief can interfere with the function of a type of white blood cell known as neutrophils, which are responsible for fighting bacterial infections like pneumonia.

The impact becomes more profound in older adults as, with age, they lose the ability to produce a hormone that can counteract this dampening effect, meaning even previously healthy elderly people can fall victim to disease following a bereavement, says the study.

Professor Janet Lord, who led the research, said: "There are a lot of anecdotes about couples who were married for 40 years when one of them passes away and then the other dies a few days later. It seems there is a biological basis for this.

"Rather than dying of a broken heart, however, they are dying of a broken immune system. They usually get infections."

The researchers came to the conclusion on an analysis of immune systems and hormone levels of 48 healthy adults aged 65 and over. Half of the group had suffered a major bereavement in the past 12 months.

They found that the antibacterial action of neutrophils from grieving participants was significantly reduced compared to those who had not suffered bereavement. They also had raised levels of the stress hormone cortisol.

Cortisol suppresses the activity of neutrophils, making them less active.

Most young healthy people produce a second hormone called DHEA, which Professor Lord and her colleagues found can counteract this affect, allowing their immune system to function normally.

With age, however, adults lose the ability to produce this second hormone and so they become more vulnerable to disease at moments of stress, say the researchers.

Lord said: "We think that what is going on is that even in previously healthy people are becoming very depressed and this has a powerful effect on the immune system. A 70-year-old has around 10 to 20 percent of the DHEA of a 30-year-old, so it may be why older people are less able to cope with bereavement."