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The Truth About Old Wives’ Tales
We’ve all heard them before. Should we be listening?
1. Don’t swim for an hour after you eat—you’ll get cramps.
This could be true if your meal was huge, says Garey Mazowita, medical director of community and long-term care at the Winnipeg Regional Health Authority. It has to do with blood flow. When you eat, blood is diverted to your digestive system to help metabolize the food. Exercising also increases blood flow, since blood carries the oxygen your muscles need to work. If you’re digesting food and exercising vigorously at the same time, there’s not as much blood available for the muscles—so they could cramp.
“But only with a huge meal, followed by remarkably vigorous exercise, is this remotely likely,” says Mazowita.
Nonetheless, as Winnipeg’s Canadian Red Cross injury prevention co-ordinator Gail Henderson Brown points out, “if you were exercising on land, you could sit down and wait for the cramp to pass. In the water, you can’t stop swimming—you’d risk drowning. So we stick with the rule, to be on the safe side.” Both Mazowita and Henderson Brown agree that light snacks followed by frolics in shallow water pose little or no risk.
2. Vitamin C prevents colds.
Rhonda Bell, a professor of agricultural, food and nutritional science at the University of Alberta, says, “There’s some evidence that a certain amount, taken in the early stages of an upper respiratory infection, acts as a preventive measure” and heads off a full-blown cold.
By “a certain amount,” Bell doesn’t mean the megadoses of thousands of milligrams some proponents urge as a panacea. London, Ont., pediatrician Fabian Gorodzinsky cautions that “research shows large amounts of vitamin C can cause diarrhea and other gastrointestinal disturbances.”
Bell suggests the best way to get vitamins is not through pills, but by eating foods that contain them.
3. You’ll catch a cold if you go out with wet hair.
Gordon Giesbrecht heads the Laboratory for Exercise and Environmental Medicine at the University of Manitoba and is a leading researcher on hypothermia—the ultimate chill. He immerses students in icy water for hours on end to do his studies. “I’ve half frozen hundreds of students,” he says, “and not one has ever caught a cold afterwards.”
It’s true, he adds, that if stress from being chilled depresses your immune system, you may be more vulnerable to a cold virus. “But the bottom line is, viruses cause colds; getting chilled doesn’t.”
4. Put butter or ice on a burn.
Since the thick, greasy stuff resembles some ointments, butter may at one time have been seen as “a handy substitute,” speculates Judy Knighton, clinical nurse specialist at the Ross Tilley Burn Centre at Sunnybrook and Women’s College Health Sciences Centre in Toronto. “But it doesn’t stop the burning process, soothe the skin or prevent tissue damage.”
And while butter at best doesn’t help, ice on a burn can make the situation worse, causing frostbite—the same sort of tissue damage as a burn. Cold water is best. It stops the burning process and prevents deeper tissue damage.
5. Chicken soup cures a cold.
Nothing cures a cold, but research hints that grandma’s chicken soup could ease symptoms. In 1993 Dr. Stephen Rennard of the University of Nebraska Medical Centre set up his test tubes and had his wife make soup from her grandmother’s recipe. He discovered that the soup inhibits the migration of white cells called neutrophils, which may contribute to bronchial congestion.
Then there’s the cysteine in chicken meat. An amino acid, it closely resembles N-acetylcysteine, a medication that thins mucus. Finally, the spices: At UCLA’s School of Medicine, researchers tested a recipe that included pungent cayenne pepper and curry. They found the capsaicin that makes peppers hot also acts like expectorants in over-the-counter remedies—it loosens congestion.
So there could be more at work here than the soothing effect of a warm liquid.
6. Drinking milk when you have a cold makes you more stuffed up.
In 1990, Australian researcher Carole Pinnock exposed 60 volunteers to a respiratory virus then recorded the milk and dairy-product intake of most of them, and with her associates, collected and weighed her subjects’ nasal secretions. The results? Milk consumption caused no increase in congestion or secretion, though a trend was observed for those with coughs. Five percent had a looser cough with a higher intake of milk and dairy products.
7. Eating carrots will improve your eyesight.
Julie Lacasse, senior clinical dietitian at the Medicine Hat Regional Hospital in Alberta, suspects this one was designed to encourage kids to eat their vegetables, but the old tale has slender roots in scientific fact.
The beta-carotene in carrots is an excellent source of vitamin A, and a deficiency of this vitamin causes night blindness (when a person can’t see well under low-light conditions). “It’s not likely to be a problem in developed countries,” says Lacasse, “where vitamin A deficiency is almost nonexistent.”
8. Children are more likely to catch infections in pediatricians’ waiting rooms.
“I really don’t think so,” says pediatrician Gorodzinsky. “Certainly during cold season, eight of ten patients in my waiting room may have colds or infections. But a child is no more likely to catch something here than in a supermarket, day-care centre, shopping mall or crowded skating rink.”
And it has nothing to do with being young.
9. Candy will rot your teeth.
Dr. Toby Gushue, past president of the Canadian Dental Association, says sticky, mushy carbohydrates like soft breads or cheesy pastas can be harder on teeth than sugar. When it comes to cavities, the real culprit is acid formed by food remnants left to break down in the mouth. This causes demineralization, the eroding of the hard, protective surface of your teeth, and leaves them vulnerable to decay-causing bacteria.
The Newfoundland dentist says those fermentable carbohydrates can do more damage than hard candy crunched in a happy swirl of saliva, which dissolves sugar fully.
10. Spinach makes your muscles strong.
Childhood hero Popeye had many virtues, but “I’m strong to the finich / ’Cuz I eats me spinach”? Wrong. There are two types of nutritional iron: heme iron, found in meat, poultry and fish, and nonheme iron from vegetables, fruits, grains and nuts. Nonheme iron is not as well absorbed by the body. Though spinach contains iron, it also has oxalates that actually discourage absorption. (We soak up only about 1.5 percent of the iron in spinach).
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