Exposure to even low levels of environmental toxins such as lead, mercury, dioxin, nicotine and ethanol could trigger asthma, allergies and autoimmune disorders like lupus, says a Cornell University researcher. Rod Dietert, professor of immunotoxicology at Cornell, told a conference that the real dangers from environmental toxins most likely occur early in life. "We are deluding ourselves to think that adult data are going to allow us to understand the risks of perinatal exposures," said Dietert, referring to the period close to the time of birth. "Exposure to certain drugs and chemicals in the last trimester can really mess things up," he added. He cited evidence that showed low doses of lead, mercury, ethanol or steroids can permanently change a developing immune system so that is out of balance for responses later in life. The same low doses of these agents do not seem to impair an adult immune system at all.
Apparently, far lower doses of toxins induce chemical changes in a fetus's immune system compared with an adult's, and exposure to these toxins during the perinatal period produces a broader number of effects than in adults.
"I think this goes a long way toward explaining the epidemic rises in allergies and autoimmune disorders," said Dietert. When an infant's immune system is altered because of toxin exposure and never attains proper functionality, the baby develops a higher risk, not only for asthma and allergies during childhood but also for autoimmune diseases and compromised antiviral and anticancer responses in later life.
Dietert advocates a more detailed two-generation screening in which information on toxins and their impact on immune systems is recorded not only for the adult mother but also for her offspring. It had been previously thought that adult-exposure safety testing when coupled with superficial two-generational tests could predict the health risks for adults as well as fetuses and children. But it is now appears that current safety testing lacks the ability to detect many early-life immunotoxic changes.
Dietert outlined a number of periods during fetal development when exposure to low levels of toxins can have long-term impacts. He said that lead can interfere with immune-dependent reproductive development and ethanol can impair the ability of immune cells to mature just before birth. "Right now, we underestimate health risks that are occurring due to early exposure," he concluded.
Source: Cornell University
