The Most Confusing Health Mysteries of the Year
Will my cell phone give me cancer?
"The jury is still out," says Linda M. Liau, MD, PhD, a UCLA neurosurgeon whose brain tumor patients often ask if cellular use is to blame. "None of the U.S. studies showed any significant correlation." But researchers from Sweden's Karolinska Institute reported in the November 2004 issue of Epidemiology that ten or more years of analog cell phone use raised the risk of developing acoustic neuroma, a benign nerve tumor. Because most of today's phones are digital, it's impossible to know whether they pose a similar risk. In January the head of Britain's National Radiological Protection Board, acting with an abundance of caution, recommended that children under 8 not use cell phones and that those between 9 and 14 use them only when it's essential. Given that cell phones have been the rage in this country only since the late 1990s, "we may see something harmful 20 years down the road," says Liau, who uses one herself but keeps the conversations short.
Which calcium sources are best absorbed by the body?
The calcium in milk, yogurt and cheese is the most readily absorbed, says Marilyn Tanner, a registered dietitian at Washington University School of Medicine in St. Louis. Although leafy greens are also a good source of calcium, some of them (including spinach and chard) contain substances called oxalates that bind to calcium and keep it from being absorbed. So stick with dairy, canned sardines and salmon, calcium-fortified orange juice, low-oxalate greens like kale and broccoli, and calcium carbonate in antacid pills. Because calcium carbonate requires stomach acid for absorption, anyone taking acid-reducing drugs like Nexium should choose calcium citrate instead.
Is organic food more nutritious?
It can be, but that depends on a number of factors, including growing conditions, how the foods are stored, and which nutrients you're looking at. Researchers at the University of Aberdeen in Scotland reported in December 2004 that organic milk from cows that grazed on clover contained more healthy omega-3 fatty acids than conventional milk did. Strawberries, corn, tomatoes and broccoli grown without chemical pesticides have higher levels of disease-fighting antioxidants than conventionally grown produce, according to analyses released in 2003 and 2004 by researchers at the University of California at Davis. But such data are still too preliminary to draw sweeping conclusions that organic is better, says Christine M. Bruhn, PhD, director of the Center for Consumer Research at UC Davis. "There is absolutely not a striking difference in nutritional value between products grown organically and those grown conventionally," she says. "If you want to support the philosophy of organic and can afford the price, buy it."
Do hair dyes cause cancer? Can pregnant women use them?
Studies have suggested that dyes, particularly dark shades, may raise the risks of non-Hodgkin's lymphoma and bladder cancer. In 2004, the American Journal of Epidemiology reported that use of the darkest permanent dyes for more than 25 years doubled the risk of non-Hodgkin's lymphoma among women who regularly colored their hair before 1980. Manufacturers have reformulated dyes since 1979, but researchers can't yet say whether newer ones are safer. In 2001 Manuela Gago-Dominguez, MD, PhD, an assistant professor of preventive medicine at USC, reported a higher risk of bladder cancer among women who used permanent dyes at least once a month for a year or longer. "The darker the color, the more arylamines," the chemicals that give dyes their color, she says. "And the more frequently you dye, the more arylamines get into your system." While there's been no proven harm to unborn children, doctors advise pregnant women to avoid permanent hair color, at least in the first trimester.
Do I need to take a daily aspirin?
A daily dose of aspirin, that century-old miracle drug that alleviates pain, reduces fever, and tames inflammation, may indeed prevent heart attacks and strokes. Although women weren't represented in the first studies of aspirin's protective powers, later ones established that it also works well for us. Still, women remain far less likely to take a daily preventive aspirin because doctors underestimate our risk. The American Heart Association recommends that women at high risk of heart attack and stroke because of diabetes, smoking, high blood pressure, or high cholesterol consider daily aspirin. Postmenopausal women and those who have had a heart attack or stroke or heart surgery should also ask their doctors about aspirin therapy. "Beginning at age 30, it would be appropriate to speak to your doctor about risk factors and possibly daily aspirin," says Thomas L. Shook, MD, a cardiologist at Good Samaritan Hospital in Los Angeles. Some doctors may recommend protecting the stomach with an acid blocker such as Prilosec, Nexium, or Prevacid.
It can be, but that depends on a number of factors, including growing conditions, how the foods are stored, and which nutrients you're looking at. Researchers at the University of Aberdeen in Scotland reported in December 2004 that organic milk from cows that grazed on clover contained more healthy omega-3 fatty acids than conventional milk did. Strawberries, corn, tomatoes and broccoli grown without chemical pesticides have higher levels of disease-fighting antioxidants than conventionally grown produce, according to analyses released in 2003 and 2004 by researchers at the University of California at Davis. But such data are still too preliminary to draw sweeping conclusions that organic is better, says Christine M. Bruhn, PhD, director of the Center for Consumer Research at UC Davis. "There is absolutely not a striking difference in nutritional value between products grown organically and those grown conventionally," she says. "If you want to support the philosophy of organic and can afford the price, buy it."
Do hair dyes cause cancer? Can pregnant women use them?
Studies have suggested that dyes, particularly dark shades, may raise the risks of non-Hodgkin's lymphoma and bladder cancer. In 2004, the American Journal of Epidemiology reported that use of the darkest permanent dyes for more than 25 years doubled the risk of non-Hodgkin's lymphoma among women who regularly colored their hair before 1980. Manufacturers have reformulated dyes since 1979, but researchers can't yet say whether newer ones are safer. In 2001 Manuela Gago-Dominguez, MD, PhD, an assistant professor of preventive medicine at USC, reported a higher risk of bladder cancer among women who used permanent dyes at least once a month for a year or longer. "The darker the color, the more arylamines," the chemicals that give dyes their color, she says. "And the more frequently you dye, the more arylamines get into your system." While there's been no proven harm to unborn children, doctors advise pregnant women to avoid permanent hair color, at least in the first trimester.
Do I need to take a daily aspirin?
A daily dose of aspirin, that century-old miracle drug that alleviates pain, reduces fever, and tames inflammation, may indeed prevent heart attacks and strokes. Although women weren't represented in the first studies of aspirin's protective powers, later ones established that it also works well for us. Still, women remain far less likely to take a daily preventive aspirin because doctors underestimate our risk. The American Heart Association recommends that women at high risk of heart attack and stroke because of diabetes, smoking, high blood pressure, or high cholesterol consider daily aspirin. Postmenopausal women and those who have had a heart attack or stroke or heart surgery should also ask their doctors about aspirin therapy. "Beginning at age 30, it would be appropriate to speak to your doctor about risk factors and possibly daily aspirin," says Thomas L. Shook, MD, a cardiologist at Good Samaritan Hospital in Los Angeles. Some doctors may recommend protecting the stomach with an acid blocker such as Prilosec, Nexium, or Prevacid.
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