Is it "feed a cold, starve a fever" or "feed a fever, starve a cold"? If you're like me, you can never keep the adage straight. No matter, though, since doctors say it's probably more folklore than solid medical advice either way.
According to Cecil Adams, the know-it-all who writes the syndicated column The Straight Dope, the dubious directive dates back to 1574, when a dictionary writer named John Withals wrote, "Fasting is a great remedie of feuer."
There is a kernel of truth in this idea, say Duke University nutrition scientists. Some small studies have suggested that eating less during a fever can trigger an immune response. Just don't take the advice too literally, the nutritionists say—starving yourself of nutrients, and especially liquids, is counterproductive.
As for feeding a cold, is having the sniffles license to double up on Ding-Dongs? Sadly, no. This idea also comes from centuries-old medical beliefs (you know, like blood-letting), when it was believed that a cold was caused by a drop in temperature and that food helped to "stoke the fire."
One bit of folk wisdom does have some merit—eating chicken soup when you have a cold really can help alleviate symptoms. Any warm liquids are soothing and can help thin mucus. And as the Mayo Clinic's Web site explains, researchers have found that chicken soup also acts as an anti-inflammatory, limiting the movement of neutrophils—immune system cells that are involved in the body's inflammatory response.
Chicken soup was suggested as a cold remedy in the 12th-century writings of Moshe ben Maimonides, an influential Egyptian Jewish physician and philosopher whose theories were based on those of the ancient Greeks. While much of his medical advice was eventually sidelined by new discoveries, the chicken soup stuck, passed down by grandmothers through the generations.
In 1993, a University of Nebraska Medical Center physician/researcher, Dr. Stephen Rennard, decided to put his wife's Lithuanian grandmother's recipe to the test and discovered the anti-inflammatory effect. His studies found that, although some canned chicken soups produced the same result, not every formulation was as effective. He hasn't been able to isolate the ingredient, or combination of ingredients, that do the trick, but he helpfully provides his wife's grandma's recipe on the university Web site. It looks pretty good, with sweet potatoes, turnips and other veggies, though, I admit, I'm partial to my own grandma's chicken soup recipe, which includes matzo balls.