(Mon, 29 Nov 2010 13:17:00 +0000)
# 5098
From the University of Michigan today a study that addresses growing concerns over two commonly used chemicals – Triclosan and Bisphenol A (BPA) - and their possible impacts on our immune systems.
The `Hygienic Hypothesis’ is a multi-faceted school of thought that contends that some of the allergies and autoimmune diseases common to modern man come about due to a lack of exposure to certain biological agents (bacteria, viruses, and even parasites) . . . particularly in early childhood.
Additionally, over the last decade research has increasingly linked the use of household cleaners (bleach, disinfectants, carpet cleaners, etc) and other chemicals (turpentine, insecticides, etc) to childhood onset asthma and allergies (see MedNews Today Asthma in kids linked to household cleaning products and chemicals).
Essentially, the hygienic hypothesis says we may be trying to be `too clean’ for our own good.
First excerpts from the press release to the study - “The Impact of Bisphenol A and Triclosan on Immune Parameters in the U.S. Population,” which appears online in Environmental Health Perspectives Nov. 30th, followed by a 4-minute audio interview with EM Clayton, one of the authors of the study.
Allison E. Aiello of the University of Michigan, is the lead researcher on this project. If the name sounds familiar it is because I’ve featured her work in the field of influenza research in the past.
I’ll follow up with some recent developments in the BPA controversy.
ANN ARBOR, Mich.—Young people who are overexposed to antibacterial soaps containing triclosan may suffer more allergies, and exposure to higher levels of Bisphenol A among adults may negatively influence the immune system, a new University of Michigan School of Public Health study suggests.
Triclosan is a chemical compound widely used in products such as antibacterial soaps, toothpaste, pens, diaper bags and medical devices. Bisphenol A (BPA) is found in many plastics and, for example, as a protective lining in food cans. Both of these chemicals are in a class of environmental toxicants called endocrine-disrupting compounds (EDCs), which are believed to negatively impact human health by mimicking or affecting hormones.
Using data from the 2003-2006 National Health and Nutrition Examination Survey, U-M researchers compared urinary BPA and triclosan with cytomegalovirus (CMV) antibody levels and diagnosis of allergies or hay fever in a sample of U.S. adults and children over age 6. Allergy and hay fever diagnosis and CMV antibodies were used as two separate markers of immune alterations.
“We found that people over age 18 with higher levels of BPA exposure had higher CMV antibody levels, which suggests their cell-mediated immune system may not be functioning properly,” said Erin Rees Clayton, research investigator at the U-M School of Public Health and first author on the paper.
Researchers also found that people age 18 and under with higher levels of triclosan were more likely to report diagnosis of allergies and hay fever.
There is growing concern among the scientific community and consumer groups that these EDCs are dangerous to humans at lower levels than previously thought.
(Continue . . . )
(Click to listen)
BPA is used primarily to make plastics, including baby bottles and the liners of some food-grade metal cans, and it has been in common use for more than 50 years.
In recent years growing concerns over the chemical’s ability to leach synthetic estrogen-like hormones from the plastic into food and liquids has prompted numerous studies.
In 2009 (see US NWR Studies Report More Harmful Effects From BPA) linked it to cardiac arrhythmias and fertility problems in babies whose mothers were exposed to the chemical.
Chemical industry experts, however, disputed these findings and criticized some of the testing methods used.
In November of 2009, the WHO and FAO released a report stating that while some `uncertainties’ existed pertaining to the risk of BPA exposure, that there has been no evidence of adverse affects in humans from exposure to BPA.
The debate continued into 2010, when in January the FDA released a document that expressed reservations over the ongoing use of products that utilize BPA (Update on Bisphenol A for Use in Food Contact Applications: January 2010)
A few excerpts from the overview include:
Bisphenol A (BPA) is an industrial chemical that has been present in many hard plastic bottles and metal-based food and beverage cans since the 1960s.
Studies employing standardized toxicity tests have thus far supported the safety of current low levels of human exposure to BPA.
However, on the basis of results from recent studies using novel approaches to test for subtle effects, both the National Toxicology Program at the National Institutes of Health and FDA have some concern about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants, and young children.
In cooperation with the National Toxicology Program, FDA’s National Center for Toxicological Research is carrying out in-depth studies to answer key questions and clarify uncertainties about the risks of BPA.
In the interim:
- FDA is taking reasonable steps to reduce human exposure to BPA in the food supply. These steps include:
- supporting the industry’s actions to stop producing BPA-containing baby bottles and infant feeding cups for the U.S. market;
- facilitating the development of alternatives to BPA for the linings of infant formula cans; and
- supporting efforts to replace BPA or minimize BPA levels in other food can linings.
Canada, meanwhile, has declared BPA to be a toxic substance, and is calling for its removal from food packaging and polycarbonate bottles likely to be used by infants (see Globe & Mail Story Canada first to declare bisphenol A toxic).
Some researchers are urging an even broader ban.
Not all scientists are in agreement over the dangers to human health from the exposure to BPA, however.
Australia and New Zealand’s Food Standards agency (FSANZ), as recently as Nov. of 2010, have stated:
- FSANZ has evaluated the safety of BPA in food, including that consumed by infants and concluded that levels of intake of BPA are very low and do not pose a significant human health risk for any age group
Last September the European Food Safety Authority (EFSA) published its latest scientific opinion, stating that there is no `convincing evidence’ for it to revise current exposure limits for BPA.
However, just 4 days ago (Nov 25th) it was announced that BPA would be banned from the manufacture of baby bottles starting in 2011 (see Reuters EU to ban Bisphenol A in baby bottles in 2011).
While the evidence against BPA is both sparse and mixed, many researchers point out that it can take years – even decades – to establish an absolute link between any chemical and its long-term health effects.
Meanwhile -as research into the matter proceeds and governments decide how to react - for better or worse, billions of pounds of BPA continue to be used in the manufacturing of plastics each year around the globe.
