HEALTH : Why We Fret About Wrong Health Threats
WASHINGTON — Like so many of her friends and neighbors, Ellen Corella has replaced well-marbled meats and cream sauces in her diet with water-packed tuna and vegetable puree.
She reads food labels, pays attention to sodium and pushes fiber at her family every chance she gets. Cruising the grocery shelves in pursuit of organic jewel yams and macrobiotic sweetener, the Maryland housewife has transformed herself into a paragon of defensive shopping.
“I’m just doing what I can to cut down our risks,†she said recently, while negotiating an aisle lined with shelves of bottled waters at a natural food shop in Washington. “When you think about it, these are life-and-death matters. I don’t want my kids eating a bunch of chemicals, and I don’t know too many people who do.â€
Battered by an almost daily torrent of worrisome reports about the hazards of what they eat and how they live, Americans have become engulfed in an epidemic--not of cancer but of fear. Increasingly, people see grave risks in the most basic elements of their lives: their food, their water, even the air they breathe.
Eating too much fat has clearly proven to be a risk worth worrying about. But many scientists say an obsessive reliance on bottled water and organic produce is foolish. They say these fears make little sense and that Americans too often overreact to the most trivial of risks while ignoring much more substantial threats to their health or safety. Over and again, they note that three things cause the vast majority of premature deaths in the United States: alcohol, tobacco and eating too much saturated fat.
‘An Inappropriate Sense’
“It worries me greatly, but the facts don’t seem to help much,†said Surgeon General C. Everett Koop. “People just have an inappropriate sense of what is dangerous. They get overly upset about minor problems. If you translate the weight and time it takes a laboratory rat to develop bladder cancer to a 200-pound man drinking Fresca (which contained artificial sweeteners), it comes out to about two bathtubs full each day. People dropped Fresca in a minute, but they continue to smoke.â€
The truth is that Americans have never been healthier.
Average life expectancy has risen steadily for decades and, except for cancers caused by smoking and exposure to the sun, cancer death rates have dropped or remained relatively stable. There is no cancer epidemic except for lung cancer, which is traced almost entirely to smoking. Yet surveys have repeatedly shown that people have never been more anxious about their health.
“People just seem to see the apocalypse everywhere they turn,†said Bruce Ames, chairman of the department of biochemistry at UC Berkeley, who was among the first to point out that natural pesticides are at least 10,000 more common than those made by man. “There are some important risks, of course. But everyone should just relax a bit and have some fun.â€
At times that seems hard to do. Provocative warnings about too much cholesterol, not enough Vitamin A and what can happen to people who don’t exercise enough--or do not exercise properly--have become part of the tapestry of American life. To some, cancer seems hidden in every meal.
The Real Odds
Yet, any person in the United States is thousands of times more likely to die of a household accident or car wreck than of cancer caused by man-made pesticides in food. In interviews with 25 shoppers buying organic produce at a local supermarket last week, nearly half said they had not worn their seat belts on the way to the store.
“Driving is a pretty risky proposition when you compare it to, say, drinking apple juice with a trace amount of Alar in it,†said Richard Wilson, professor of physics at Harvard University, an expert in comparing risks. “But everyone thinks he’s a better driver than the next guy. Alar is something we have no control over--we can’t even be sure if it’s in there or not.
“It’s hard for most people to develop a perspective on risks,†he continued. “After all, how many of us really know what it means when they say the risk of something is one in a million?â€
Sorting out the risks in a normal life is a tricky business.
For example, more than 30% of regular smokers will die from some disease connected to their habit, losing an average of 8.3 years from normal life expectancy. But many people react equally or more forcefully to the evidence that there may be a 1-in-a-million risk of getting cancer from chemicals found in drinking water.
One reason most risks are difficult to gauge is that most people do not reason in purely statistical terms about their lives. Also, most people make deep distinctions between risks they can control, such as smoking, and those foisted on them, such as asbestos in the walls of a school.
“It doesn’t really do much good to say, ‘Cigarette smoking kills far more people than pesticides, so let’s forget about pesticides,’ †said Michael Jacobson, executive director of the Center for Science in the Public Interest. “The fact is that these things, like Alar, appear to be a modest problem and we shouldn’t ignore them simply because other problems are worse.†In many cases, people appear to be searching for a degree of certainty that science cannot provide.
Big Questions
How directly will weight loss affect the development of heart disease? Is a sunburn really going to cause cancer? If a rat gets cancer from consuming a huge amount of diet soda in a short time, will two sodas a day for 30 years do the same thing to a human? Why did Uncle Jake live to be 90 if eating steak every day is so bad?
None of those questions can be answered with finality. The link between diet and heart disease has been made firmly over the last decade. But genetics often plays a major role that confounds the dietary odds. And researchers have long known that the easiest way to reduce the cancer rate in laboratory animals is simply to give them less food.
The incidence of skin cancer caused by exposure to the sun is increasing rapidly, but nearly everybody knows healthy elderly people who have spent their lives in the sun without using a drop of sun block. Obesity contributes dramatically to death from heart disease, according to dozens of government studies, but one need not look long before finding old people who are fat.
“That’s what I call the ‘My uncle had an Edsel and it ran fine’ problem,†said Park Dietz, a professor of law and psychiatry at the University of Virginia, and a specialist on the behavior of large groups. “In most people’s thinking, a single familiar case outweighs all the data from the opposite direction.â€
People have a sliding scale of what they consider to be an acceptable risk. Unknown fears always seem to outrank familiar ones. Driving, drinking or combining the two is something a person chooses whether to do. Consuming fruit with pesticides in it usually is not.
Equal risks are rarely treated equally. Aflatoxin and dioxin are both among the most potent of cancer-causing chemicals. But dioxin, which is manufactured in tiny amounts during processes such as bleaching paper, is often opposed by environmental groups because it is an artificial chemical.
Nobody has tried to ban aflatoxin, a natural carcinogen that can frequently be found in similarly minuscule amounts in such common foods as peanut butter.
“Nobody knows anybody who got cancer from eating a peanut butter sandwich,†said Harvard’s Wilson. “But the risk of eating a peanut butter sandwich every day is greater than the dioxin risk if it’s calculated in a similar way.â€
