Got a cold or flu? UNMC researcher says try chicken soup to ease symptoms

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Though University of Nebraska Medical Center physician and researcher Stephen Rennard, M.D., is recognized around the world for his expertise in lung disease, it’s his chicken soup scientific research study that has gained the most attention.
Dr. Rennard found that chicken soup contains a number of substances, including an anti-inflammatory mechanism, that might ease the symptoms of upper respiratory tract infections.
A challenge outside the normal realm of scientific research, and curiosity about the long-touted folk medicine, led him to embark on an off-beat study to see whether chicken soup may indeed have medicinal value.
Dr. Rennard, Larson Professor of Medicine in the pulmonary and critical care medicine section at UNMC, had for years watched his wife, Barbara, cook her grandmother’s chicken soup recipe when a cold was going around their family of 10. Known as “Grandma’s Soup,” the recipe includes chicken, onions, sweet potatoes, parsnips, turnips, carrots, celery stems, parsley, salt and pepper.
“She told me the soup was good for colds,” Dr. Rennard said. “I’ve heard that a zillion times. Then I started to think, ‘Well, maybe it has some anti-inflammatory value.’ Everyone’s heard this from their mother in many cultures. No one seems to have a monopoly on the insight of the value of chicken soup.”
The suspected benefits of chicken soup were reported centuries ago. The Egyptian Jewish physician and philosopher, Moshe ben Maimon, recommended chicken soup for respiratory tract symptoms in his 12th century writings which were, in turn, based on earlier Greek writings. But, there’s little in the literature to explain how it works.
So in 1993, he challenged the age-old folk remedy by taking chicken soup from the kitchen to the laboratory. Three batches of soup prepared in the home of Dr. Rennard and studied in the laboratory under controlled conditions. For comparison purposes, commercial soups were obtained from a local supermarket and prepared according to the directions on the label.
Researchers collected neutrophils from blood donated by healthy volunteers.
The study’s focus was to find out if the movement of neutrophils – the most common white cell in the blood that defends the body against infection – would be blocked or reduced by chicken soup. Researchers suspect the reduction in movement of neutrophils may reduce activity in the upper respiratory tract that can cause symptoms associated with a cold.
In the laboratory, UNMC scientists diluted the soup and subjected the neutrophils to several variations of the soup, including vegetables, chicken and a combination of the ingredients. The team found the movement of neutrophils were reduced. Samples taken during the initial stages of the soup with chicken broth alone were not found effective in inhibiting neutrophil movement.
Though researchers were not able to identify the exact ingredient or ingredients in the soup that made it effective against fighting colds, they theorize it may be a combination of ingredients in the soup that work together to have beneficial effects.
“All vegetables and the soup had activity,” Dr. Rennard said. “I think it’s the concoction.”
Many of the store-bought soups had the same inhibitory effect.
Researchers noted that “Grandma’s soup” has several unusual features. It contains strained vegetables. Dr. Rennard noted, however, that the inhibitory activity was observed with several other recipes that lack the particles from vegetables. “Thus,” he said, “while the identity of the biologically active materials is unknown, it seems likely they are water-soluble or extractable. Pureed carrots or other vegetables are not recommended as a remedy while chicken soup is.”
“A variety of soup preparations were evaluated and found to be variably, but generally, able to inhibit neutrophil chemotaxis,” he said. “The current study, therefore, presents evidence that chicken soup might have an anti-inflammatory activity, namely the inhibition of neutrophil migration.”
The soup also may improve rehydration and nutrition in the body, he said, and the psychological and physical comfort soup provides may also have a placebo effect.
He submitted a scientific abstract of the results of his study in 1993, he said, mostly because of its amusement value. His abstract was accepted and he presented it to hundreds of physicians and researchers during a conference in San Francisco. Then in October 2000, his study was published in CHEST, the journal of the American College of Chest Physicians.
Dr. Rennard’s study has been featured more than 1,000 times in the mass media. “When I’m gone, out of all the research I’ve done, I’ll probably be remembered most for my research on chicken soup,” Dr. Rennard said.
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