Tag Archives: chemicals

Curb Exposure to Harmfull Chemicals by Changing Your Diet

By Sarah (Steve) Mosko
Special to the Voice

Endocrine disrupting chemicals (EDCs) are synthetic substances known to play havoc with hormone and organ systems in lab animals, and it’s well-documented that the urine of most Americans  tests positive for an alarming number of them. EDCs are found in a wide array of everyday consumer products and also find their way into air, dust and even foods.

A new study confirms for the first time that dietary practices – like whether you select fresh versus canned fruits and vegetables, microwave foods in plastics, or drink from plastic bottles – have a rapid and hefty impact on one’s body burden of at least two EDCs known to interfere with normal organ development in animals and maybe humans: bisphenol A (BPA) and di-ethylhexyl phthalate (DEHP).

BPA is a key component of shatter-proof polycarbonate plastics, like many personal sports bottles or 2-5 gallon water bottles, as well as the epoxy lining of canned foods and soda. BPA is known to migrate into the contents of such containers, and it is well-established that BPA mimics the hormone estrogen.

A large body of evidence pointing to a possible role of BPA in such diverse medical conditions as obesity, diabetes, infertility and breast & prostate cancers has led to legislation in a number of states to reign in human exposure, especially in infants and young children who are thought to be most vulnerable to developmental derailments from EDCs. In the European Union, BPA is classified as a reproductive toxicant.

DEHP is another EDC produced in high volume and found in many consumer goods, including food packaging like some food wrap films. It is commonly used as a softening agent in plastics made of polyvinyl chloride, and because it is not chemically bonded to the plastic polymer, it too is free to migrate out during routine use.

Effective 2009, the U.S. federal government banned the use of DEHP (and other phthalates) in children’s toys and child care products, and several states have passed similar restrictions to reduce exposure in youngsters based on research showing that DEHP can inhibit testosterone synthesis and might disrupt the development of the male sexual tract and impair semen quality.

While most research on BPA and DEHP has, by necessity, been conducted on lab animals – leaving the impact on humans uncertain – it is appropriate that health conscious consumers and parents have an interest in limiting their own and their families’ exposure to known EDCs while scientists sort out the actual threat to humans.

BPA and DEHP are well-suited for a study of how dietary choices impact human exposure to EDCs because both can be monitored through the urine. Furthermore, their biological half-lives (a measure of how quickly the body gets rids of them) are short enough that the effects of a manipulation should show up in the urine within a few days.

Researcher Ruthann Rudel of the Silent Spring Institute in Massachusetts headed the study which followed five families of four (two parents and two children each, aged 3-12 years) during a three-day dietary intervention designed to eliminate obvious food-related sources of BPA and DEHP. Exposure levels to BPA and DEHP were determined for a few days just before, during and right after the three-day intervention by measuring BPA and the breakdown products (i.e. metabolites) of DEHP in daily urine samples.

The families were all from the San Francisco area and were selected based on the likelihood that they were being exposed to BPA or DEHP in their usual diets by way of consuming canned foods/sodas or at least two of the following: drinking from personal water bottles or 2-5 gallon polycarbonate bottles in office coolers; microwaving foods in plastic; or eating restaurant food.

Families maintained their usual eating habits for two days before and for three days after the intervention period. During the intervention, they ate a uniform menu from a caterer who prepared meals from fresh and organic fruits, vegetables, grains and meats and without use of plastic utensils or non-stick cookware. Glass storage containers were used in which microwaving was allowed too, but only after the plastic lid (non-BPA) had been removed.

Coffee made with a French press or ceramic drip was allowed but not from a plastic coffee maker or from a café.

Because there was considerable person-to-person variability in the baseline concentrations of the EDCs detected in the urine samples, the researchers arrived at an estimate of the “typical” level by using a conservative measure of the group’s “average” called the geometric mean which is designed to compensate for such variability.

The most impressive findings of the study were that, during the intervention, BPA in the urine of adults and children fell by about two-thirds and the metabolites of DEHP were reduced by more than half. The individuals whose exposure to BPA and DEHP was highest while eating their routine diet showed the greatest drops during the intervention.

BPA in the urine reverted back to nearly pre-intervention levels as soon as families were free to resume their usual diets, and the metabolites of DEHP also rose again within a few days but not yet to the point of a statistically significant difference at the time of the final urine collection.

The upshot of this study is that food ingestion seems to be a major source of human exposure to BPA and DEHP and, because the body is able to eliminate these chemicals in a matter of days, moving to a “fresh foods” diet can have a pretty rapid and measureable impact. The study authors surmised that plastic food packaging and restaurant meals were the most likely dietary sources of BPA and DEHP for the participants in their study.

Perhaps the other take home message is that the old adage “you are what you eat” still holds but with the unhappy twist that, because synthetic chemicals have come to define most aspects of everyday modern life, unless you choose foods mindfully you’re probably eating plenty of questionable stuff you didn’t bank on.

The study was published in the online 30 March 2011 issue of Environmental Health Perspectives. For six simple steps to avoid BPA and phthalate in foods, visit The Silent Spring Institute (www.silentspring.org/six-steps.pdf).

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‘BPA-Free’ Label no Guarantee that Plastic is Safe

By Sarah (Steve) Mosko
Special to the Voice

The bad reputation recently earned by BPA or bisphenol A, a chemical constituent of polycarbonate resin plastics, is probably well-deserved because it is an estrogen hormone mimic linked in hundreds of studies to potentially adverse health effects in mammals ranging from cancers and infertility to diabetes and obesity.

Fetal and juvenile mammals are particularly sensitive to exposure to low doses of estrogen mimics, raising particular concerns about BPA-containing plastics that infants and toddlers might encounter. Consequently, some manufacturers of baby bottles, water bottles and other plastic products are now marketing items as “BPA-free.”

Unfortunately, a “BPA-free” label offers no assurance that a product won’t leach chemicals with estrogenic activity (EA), according to a study appearing in the online March 2 issue of Environmental Health Perspectives. In fact, the study measured EA leaching from all sorts of food-contact plastic products made with resins other than polycarbonate.

Plastics are produced by polymerizing (linking together) plastic monomers into long chains. A wide array of chemical additives can be thrown into the brew to achieve desired characteristics like flexibility, transparency or resistance to breakdown in sunlight.

Because polymerization is almost never complete, the leftover plastic monomers are free to migrate out. The additives can migrate out too because they are just ‘mixed in’ rather than chemically bonded to the polymer.

The mixture of chemicals that went into a final product is considered proprietary information, but the study authors point out that a single plastic component might be made of 5-30 chemicals. An item made of multiple plastic components, like a baby bottle, could consist of upwards of 100 chemicals, any of which might migrate out.

Furthermore, the conditions to which plastics are often exposed in everyday use, like microwaving, sunlight and/or dishwashing, might encourage chemicals to leach out. Leaching might also occur faster or slowing depending on the type of food or liquid contained within a plastic.

Complicating the picture even further, a chemical constituent showing no intrinsic EA might be altered by the manufacturing process into one with EA.

Thus, the researchers in this study recognized that, to appreciate the real potential for leachates with EA, they would need to test finished plastic products under various conditions, like after sunlight exposure or microwaving, and using multiple extraction solvents (saline or ethanol) to mimic different foods/liquids.

The assay they used for EA is a sensitive, accepted screen for EA based on the ability of a test substance to mimic the binding of natural estrogen to estrogen receptors in the nuclei of a line of breast cancer cells (MCF-7) and, consequently, to trigger cell proliferation. The EA of any substances testing positive is this assay is confirmed by showing that the cell proliferation can be prevented by a compound known to block the action of natural estrogen.

It is generally assumed that plastics fashioned from common resins other than polycarbonate – like polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET) – do not release chemicals exhibiting EA. This study thoroughly debunks this supposition as it reports that most of a sample of 455 commercially available products tested positive for EA.

The authors purchased a wide variety of plastics items used to contain foodstuffs from large retail stores in the Austin, Texas and Boston, MA areas – plastic bags, food wrap, baby bottle components, flexible and rigid packages, and deli containers – none of which were known to contain BPA.

Between 44 and 100 percent of the product types showed EA using either saline or ethanol as solvents. Plastic bags and food wrap topped the list at 98 and 100 percent, respectively.

Perhaps most alarming, 89 percent of baby bottle components leached EA.

Some of the products tested released chemicals exhibiting more EA than BPA-containing products.

No one type of commonly used plastic resin came out smelling all that much better than the others as the number of samples testing positive for EA ranged from 50 percent for PS products to 75 percent for those made of PET. PLA (polylactic acid), a newer resin derived from corn and marketed as compostable under certain conditions, ranked highest with 91 percent of PLA products showing EA.

Exposing the products to microwaving, moist heat or especially UV light tended to promote greater EA. Whether or not products had contained a food substance at time of purchase did not alter the overall results, indicating that the container rather than any previous contents was the more important source of EA.

Products obtained from large retailers that specialize in organic inventories were just as likely to test positive for EA as counterparts purchased from conventional stores.

The researchers also examined commercially available plastic monomers used in plastic manufacturing, and a number of them exhibited EA. More than 50 common plastic additives they tested exhibited EA too. Among them were BHA and BHT, the oldest and most commonly used antioxidants in food contact plastics. Antioxidants are critical to plastic manufacturing because they inhibit the breakdown of the polymer chain.

Among the chemicals showing EA, the researchers identified a particular molecular configuration (phenolic) which they feel explains the EA. They proposed that the problem of leachates with EA from food contact plastics can be solved by substituting already available plastic monomers and additives which do not exhibit this configuration in both their original state and after exposure to conditions like UV light or heat, yet still yield the desirable properties of popular plastics.

The lead researcher in this study, George Bittner, Ph.D., and some of the co-authors participate in companies that develop and market chemicals that do not exhibit EA (Certichem, Inc. and PastiPure, Inc.). In this research report, they claim that switching to plastics which do not release chemicals with EA would add little or nothing to production costs.

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