If it’s legal, it must be safe, right? Actually, not always. One of the many chemicals deemed legal to use in manufacturing, bisphenol-a (BPA), is contributing to changes in these social attitudes. BPA is an increasingly unpopular chemical, with many companies using the phrase “BPA-free” as selling points for their products. The most well-known effect of BPA exposure may be hormone disruption, but did you know that BPA may also increase the risk of asthma?
Asthma on the Increase
Asthma is a chronic respiratory illness that has unfortunately been increasing in incidence. It is characterized by over-sensitive airways that lead to airflow obstruction, and is inflammatory. Asthma is the third leading cause of hospitalization for children and teenagers under the age of 15. I used to have asthma, but kicked it at the age of 8 by swimming in a heated pool. Others are not so lucky, as 75% of children still have symptoms of asthma when they reach adulthood.
Asthma is caused by an interaction between genes and environmental factors, including BPA exposure.
Studies on Possible Link Between Prenatal BPA and Asthma
One study of 657 pregnant women tested for their BPA levels during the first and third trimesters showed that higher prenatal levels of BPA were linked with a 20% higher risk of their babies wheezing.
In another study, urinary BPA levels were tested when mothers were 16 and 26 weeks pregnant, as well as at the time of the children’s birth. Above average BPA levels were associated with more than double the risk of children wheezing at age 6 months, but not at 3 years old. It has also been demonstrated that every 10-fold increase in BPA levels was associated with a 55% increase in the risk of wheezing from birth to five years.
In two other studies, one involving almost 400 mothers, higher BPA levels 16 weeks into pregnancy were linked with higher risks of wheezing, one showing a 20% increase, the other a 79% increase.
BPA exposure in childhood may or may not increase the risk of asthma. One study found a 40-50% increase in asthma in children 3-7 years old. Two others, however, found an increased risk only in girls.
Constant Exposure to BPA Lets it Accumulate
Why would a commonly used product cause diseases such as asthma? And don’t we have organs meant to protect us from exposure to toxic substances? Well, even though BPA has only a 6-hour half-life in the body, we are often in contact with it so much that little to no accumulation wouldn’t make much difference. Many people also habitually use the same type of products; I have “my brand” and you have “your brand.”
How BPA may Cause Asthma
The way that BPA may cause asthma is by interfering with immune function, which may explain the mixed results in research. It may swing the immune response in favor of the T-helper 1 (Th1) cells; in naturopathic circles, Th1 dominance is known to put our patients at risk of certain illnesses. Th2 dominance also comes with risks.
Some studies have shown that BPA could create Th2 dominance. BPA may increase the production of pro-allergic immune chemicals such as IL-4 and IgE, which instruct a type of immune cell to start an inflammatory response.
BPA may also cause oxidative stress, which has been known for many years to promote diseases (including general aging). The well-known effects of oxidative stress are why popular health magazines and websites will tell you to drink green tea and eat brightly-cultured fruit and vegetables.
Overall, while human studies show mixed findings because of individual differences, we are given enough reason to avoid this ‘plastic’ chemical.