It seems that granny was right all along - chicken soup is really good for colds.
A study by a team of scientists at Nebraska Medical Center in the United States has found that the broth contains ingredients that act as anti-inflammatory agents.
These could ease some of the most irritating symptoms of the common cold, confirming a folk remedy that dates back at least eight centuries. In 12th-century writings, the Egyptian Jewish physician Moshe ben Maimonides recommended chicken soup for respiratory-tract infections, though he is believed to have drawn on older Greek teachings for his information.
The team from Nebraska, led by Stephen Rennard, looked at the properties of the broth to test the veracity of the ancient remedy. Their results are published in the journal Chest .
Rennard said: "While the identity of the biologically active materials is unknown, this well-controlled study provides limited evidence that chicken soup could have an anti-inflammatory activity. Since many of the symptoms that follow upper respiratory-tract viral infections may well be due to the inflammatory response, the current study may have clinical relevance."
The scientists used a recipe that involved boiling chicken and a mixture of vegetables, such as onions, turnips and carrots, for an hour.
They studied the ability of the broth to inhibit the activity of white blood cells called neutrophils, which play a vital role in removing bacteria and unwanted particles from the body.
The many viruses responsible for the common cold trigger the release of proteins called cytokines from infected cells, leading to a host of responses from the body's immune system, which, in turn, causes inflammation of the upper respiratory tract.
Neutrophils are believed to be attracted to the infected area by this protein cascade, where they stimulate the release of mucous, which may play a role in classic symptoms of a cold infection, such as coughing.
In laboratory tests, elements of chicken soup appeared to stop these white blood cells from responding to the chemical stimuli that the body uses to summon them.