Autoimmune Disorders
May Be Triggered By
Environmental Factors
By Adam Pasick

(Note - Canola Oil has been tagged as the cause of 35,000 cases of autoimmune diseases in many in the US and Canada?)
NEW YORK - What's to blame when our bodies' defenses turn against us? New research out this month indicates that environmental factors, ranging from ultraviolet radiation to industrial chemicals, may be the cause of autoimmune disorders like rheumatoid arthritis and lupus.
"The concern is that there are these chemicals out there in the environment, and could be at a concentration high enough to produce autoimmune diseases," said Robert Luebke, a research biologist for the Environmental Protection Agency.
Previous research on autoimmune disorders, which affect about 3 percent of the population, has centered on sufferers' inherited susceptibility to these diseases, and some experts think infectious agents such as viruses also play a role.
But The National Institute of Environmental Health Sciences, part of the National Institutes of Health, has published a special supplement to its medical journal Environmental Health Perspectives exploring the link between environmental agents " anything we eat, drink, breath, or absorb into our bodies " and autoimmune disorders.
In the journal, a group of researchers from the University of California-Davis examined a long list of common xenobiotic (nonliving) substances and found that many trigger can an autoimmune response, meaning they produced high levels of autoantibodies in human or animal research subjects. The presence of autoantibodies indicates the immune system is attacking its own tissue (see sidebar for details).
The list includes: * Common chemicals such as mercury and iodine; * Vinyl chloride, which is used to manufacture PVC plastic; * Canavanine, a substance produced by alfalfa sprouts; * Silica, one of the most common elements in the Earth's crust; * Ultraviolet radiation and ozone, which a produce a flood of free-floating oxygen ions that can severely damage the body " especially the immune system.
Another paper by Evelyn Hess of Cincinnati Medical Center lists additional suspects: * Some types of hair dye * Heavy metals like gold and cadmium * Rapeseed (canola) oil, responsible for 35,000 cases of an autoimmune diseases in Spain; * L-tryptophane, the naturally occurring hormone that makes you sleepy after eating a Thanksgiving turkey but which until recently was sold as an over-the-counter dietary supplement. It was traced to an outbreak of a lupus-like disease in 1990 in the U.S., and was subsequently banned for public sale by the Food and Drug Administration.
Why Mostly Women?
Researchers also want to know why autoimmune diseases disproportionately affect women: More than 70 percent of sufferers are female.
"For almost all autoimmune diseases, women are at greater risk for men," said Glinda Cooper, an epidemiologist with the NIEHS Environmental Diseases and Medicine Program and co-author of one of the journal articles.
The answer may lie in women's elevated levels of estrogen, which some theorize damages the body's immune system over time. "For some of the autoimmune diseases, the risk is highest in the reproductive years when estrogen levels are highest," Cooper noted.
Another intriguing theory suggests that women " or, more specifically, mothers " are prone to autoimmune disorders because some of the fetus' cells inevitably get mixed up with mother's, causing an overzealous immune-system response when T-cells recognize the presence of an intruder.
The Single-Cause Fallacy
Despite autoimmune researchers' newfound focus on environmental factors, experts suspect that they will never track the diseases to a single cause. More likely, some people are predisposed to autoimmune diseases, but the disorders don't occur without an environmental trigger.
Hess writes that "It would appear that for any one compound or environmental agent, genetic factors may differ."
"There are many people exposed to purported risk factors," seconded Dr. G. Wendell Richmond, a private practice immunologist in Oakbrook, Ill. "But only a few come down with the diseases. That suggests a large genetic factor."
As interest grows in diseases like lupus and rheumatoid arthritis " Congress earmarked $30 million in the 1999 NIH budget to study autoimmune disorders " researchers agree environmental causes are now an important part of the scientific effort.
"The consensus coming out of the journal and the workshop is that there appears to be a role of environmental influences that would be worthwhile to pursue," Cooper said.