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 The research finding of dogs having elevated levels of the endocrine disruptor bisphenol A (BPA) from eating canned food mirrors what is happening to humans - eating canned food raises BPA levels in a person. The study also found that elevated BPA levels resulted in changes in the gut microbiome (the community of microbes living in the gut). Specifically, they found the abundance of a number of bacteria species increased or decreased depending on BPA levels in the dogs. This is not good.

This is of concern because BPA  is linked to a variety of health problems. [See all posts.] So it's best to minimize exposure to BPA, BPS, and other hormone disrupting chemicals, and also "BPA-free" products (which usually contain BPS). The BPA is in the lining of the cans used in canned food, and this leaches into the food. Unfortunately, dog food cans thought to be BPA-free in the study also contained BPA, which then leached into the dog food.  From Futurity:

Dogs have 3X more BPA after eating canned food

Researchers saw a three-fold increase in BPA levels in dogs who ate canned dog food for two weeks. They also saw changes in the dogs’ gut microbesBisphenol A (BPA) is a widely used industrial chemical found in many household items, including resins used to line metal storage containers, such as food cans. The chemical can disrupt hormones and is linked to a range of health problems. “Bisphenol A is a prevalent endocrine-disrupting chemical found in canned foods and beverages,” says Cheryl Rosenfeld, an associate professor of biomedical sciences in the University of Missouri College of Veterinary Medicine....

Dog owners volunteered their healthy pets for the study. Blood and fecal samples were collected prior to the dogs being placed on one of two commonly used, commercial canned food diets for two weeks; one diet was presumed to be BPA-free. Robert Backus, an associate professor in the veterinary medicine and surgery in the College of Veterinary Medicine, and other researchers on the team then analyzed the cans and the food contained in the cans for BPA levels and performed gut microbiome assessments.

“The dogs in the study did have minimal circulating BPA in their blood when it was drawn for the baseline,” Rosenfeld says.“However, BPA increased nearly three-fold after being on the either of the two canned diets for two weeks. We also found that increased serum BPA concentrations were correlated with gut microbiome and metabolic changes in the dogs analyzed. Increased BPA may also reduce one bacterium that has the ability to metabolize BPA and related environmental chemicals.”

“We share our homes with our dogs,” Rosenfeld says. “Thus, these findings could have implications and relevance to humans. Indeed, our canine companions may be the best bio-sentinels for human health concerns.”

A chemical frequently used in place of BPA called BPS (bisphenol S) and found in "BPA-free" products is also an endocrine disruptor. This also has negative health and behavioral effects. In this study the effects were seen in mice, but they are worrisome. Makes you wonder, what are all the effects in humans? From Science Daily: Plastics compound, BPS, often substituted for BPA, alters mouse moms' behavior and brain regions

In the first study of its kind, environmental health scientists and neuroscientists examined the effects of the compound bisphenol S (BPS) on maternal behavior and related brain regions in mice. They found subtle but striking behavior changes in nesting mothers exposed during pregnancy and lactation and in their daughters exposed in uteroBPS, found in baby bottles, personal care products and thermal receipts, is a replacement chemical for BPA and was introduced when concern was raised about possible health effects of that plastic compound.

Studies are accumulating evidence that the hormone disrupting effects of compounds BPA (bisphenol A) and BPS (the common substitute for BPA) have numerous negative health effects in humans, including reproductive disorders. But now a second BPA substitute - BPSIP - is also being found in humans, and may be even more persistent than BPA and BPS. This is because they're all chemically similar, and all three are endocrine disruptors. This article points out that they have slightly different effects, and when we are exposed to more than one of them (which we are), then the health effects will be even more worrisome.

Unfortunately these plasticizers are in products all around us, and so detected within almost all of us. They're in food packaging containers (and therefore in food), water bottles, can linings, toys, personal care products, thermal paper products such as cash receipts, etc. Canned foods are considered one of the most significant routes of human exposure to bisphenol A (BPA).

Other endocrine disruptors include phthalates - so read personal care product labels to avoid these. Another way to lower exposure to endocrine disruptors is to buy and store food not in plastic containers, but in glass containers or stainless steel. Don't microwave food in any sort of plastic containers. Avoid products with fragrances in them, including air fresheners. Avoid flexible vinyl (e.g. shower curtains). (For all posts on endocrine disruptors, and an article from National Institutes of Health.) From a research article by Liza Gross in PLOS Biology:

Wreaking Reproductive Havoc One Chemical at a Time

Bisphenol A (BPA), unlike DES, remained obscure until the 1950s, when chemists tapped it to make polycarbonate plastics and epoxy resins. BPA now tops the list of high-volume chemicals, and is found in numerous consumer products, including water bottles, food packaging containers and can linings, and thermal paper products like cash receipts and boarding passes (Fig 1). And because it can leach out of products, it’s been detected in the urine of nearly every person tested. It’s also been found in breast milk, follicular and amniotic fluid, cord blood, placental tissue, fetal livers, and the blood of pregnant women ...continue reading "Endocrine Disruptors BPA, BPS, and Now BPSIP"

Some more bad news about BPA and other endocrine disruptors (hormone disruptors) such as the phthalate DEHP. Bottom line: Avoid plastics, BPA, BPS and other BPA substitutes (they're chemically similar and seem to have similar health effects) as much as possible. Most canned food has BPA or BPA substitutes in the can linings. Use glass and stainless steel to store food, microwave food in dishes (not in plastic containers or packages). Go to the Environmental Working Group site for more information on product information, what to avoid, and what to look for and get instead.

From Science daily: BPA substitute can trigger fat cell formation: Chemical used in BPA-free products exhibits similar endocrine-disrupting effects

Exposure to a substitute chemical often used to replace bisphenol A in plastics can encourage the formation of fat cells, according to a new study. The replacement chemical, bisphenol S, has a slightly different chemical structure than bisphenol A (BPA), a known endocrine disruptor. As of 2014, nearly 100 epidemiological studies have been published tying BPA to health problems, according to the Introductory Guide to Endocrine-disrupting Chemicals published by the Society and IPEN, a global network that supports sound chemicals management.

Concerns about BPA's health effects have encouraged some consumers to purchase food containers labeled "BPA-free." BPA-free products often contain bisphenol S (BPS)or other substitutes, but researchers have raised concerns that these replacements also interfere with the body's hormones and may pose similar threats to public health."Our research indicates BPS and BPA have comparable effects on fat cells and their metabolism," said the study's senior author, Ella Atlas, PhD, of Health Canada, the federal department responsible for helping Canadians maintain and improve their health. 

A report (a collaborative effort of 5 organizations) that looked for the presence of BPA and BPA substitutes in the linings of food cans from major food companies. And yes, they found BPA in most cans (67%). From the group Toxic Food Cans: Buyer Beware: Toxic BPA and regrettable substitutes found in the linings of canned food

This study set out to analyze the interior coatings and lids of nearly 200 canned foods collected in 19 states and one Canadian province to determine whether the use of bisphenol A (BPA) continues to be widespread among major national brands and retailers of canned foods. We also wanted to determine what replacement materials for BPA-based epoxy are being used by retailers and manufacturers and the extent to which those companies have studied the safety of those materials.

Our findings were alarming: This report validates our concerns that, despite consumer demand for BPA-free cans, 67 percent (129 of 192) of the cans we tested contained BPA-based epoxy in the body and/or the lid. Our investigation also found, for the first time, that some retailers and brands have replaced BPA with PVC, made from vinyl chloride, a carcinogen.

BPA is a hormonally active chemical. The scientific evidence linking BPA exposure to harm in humans is compelling and growing: More than 300 animal and human studies have linked exquisitely small amounts of BPA exposure, measured in parts per billion and even parts per trillion, to a staggering number of health problems, including breast and prostate cancer, asthma, obesity, behavioral changes (including attention deficit disorder), altered development of the brain and immune system, low birth weight and lowered sperm counts.

This study looked at plasticizers called phthalates (which are commonly found in medical tubes), and which also have endocrine disrupting effects. From Medical Xpress:  Attention deficit after kids' critical illness linked to plasticizers in medical tubes

Children who are often hospitalized in intensive care units are more likely to have attention deficit disorders later, and new research finds a possible culprit: a high level of plastic-softening chemicals called phthalates circulating in the blood. The researchers.....suggest these chemicals, which are added to indwelling medical devices such as plastic tubes and catheters, seep into the child's bloodstream.

"Phthalates have been banned from children's toys because of their potential toxic and hormone-disrupting effects, but they are still used to soften medical devices," said lead researcher Sören Verstraete, MD, a PhD student at KU (Katholieke Universiteit) Leuven in Leuven, Belgium. "We found a clear match between previously hospitalized children's long-term neurocognitive test results and their individual exposure to the phthalate DEHP during intensive care."

Di(2-ethylhexyl)phthalate, or DEHP, is the most commonly used plastic softener in medical devices made of polyvinyl chloride (PVC). Verstraete called the use of medical devices containing this phthalate "potentially harmful" for the brain development and function of critically ill children.

Once again, research shows that "BPA-free" plastic does not mean it is safer than BPA plastic. Both BPA and BPS (the usual replacement for BPA) leach estrogenic chemicals into the foods and beverages, which means negative health effects when ingested. Both BPA and BPS mimic the effects of estrogen, as well as the actions of thyroid hormone. Yes, this study was done on zebrafish, but think of them as "the canaries in the mine" - if it affects them, it could affect humans also, especially developing fetuses and young children.

BPA  and BPS can leach into food, particularly under heat, from the lining of cans and from consumer products such as water bottles, baby bottles, food-storage containers, sippy cups, and plastic tableware. BPA can also be found in contact lenses, eyeglass lenses, compact discs, water-supply pipes, some cash register and ATM receipts, as well as in some dental sealants. A good way to minimize exposure to BPA , BPS, and other estrogenic chemicals is to try to avoid food and beverages in plastic containers and cans, but instead try to buy and store food in glass containers, jars, and bottles. From Science Daily:

'BPA-free' plastic accelerates embryonic development, disrupts reproductive system

Companies advertise "BPA-free" as a safer version of plastic products ranging from water bottles to sippy cups to toys. Many manufacturers stopped used Bisphenol A to strengthen plastic after animal studies linked it to early puberty and a rise in breast and prostate cancers.Yet new UCLA research demonstrates that BPS (Bisphenol S), a common replacement for BPA, speeds up embryonic development and disrupts the reproductive system.

Using a zebrafish model, Wayne and her colleagues found that exposure to low levels of BPA and BPS -- equivalent to the traces found in polluted river waters -- altered the animals' physiology at the embryonic stage in as quickly as 25 hours. "Egg hatching time accelerated, leading to the fish equivalent of premature birth," said Wayne, who is also UCLA's associate vice chancellor for research. "The embryos developed much faster than normal in the presence of BPA or BPS."

The UCLA team, which included first author Wenhui Qiu, a visiting graduate student from Shanghai University, chose to conduct the study in zebrafish because their transparent embryos make it possible to "watch" cell growth as it occurs.... In a second finding, the team discovered that the number of endocrine neurons increased up to 40 percent, suggesting that BPA overstimulates the reproductive system.... "We saw many of these same effects with BPS found in BPA-free products. BPS is not harmless."

After uncovering her first finding about BPA in 2008, Wayne immediately discarded all of the plastic food containers in her home and replaced them with glass. She and her family purchase food and drinks packaged in glass whenever possible. "Our findings are frightening and important," emphasized Wayne. "Consider it the aquatic version of the canary in the coal mine."

Finally, the researchers were surprised to find that both BPA and BPS acted partly through an estrogen system and partly through a thyroid hormone system to exert their effects"Most people think of BPA as mimicking the effects of estrogen. But our work shows that it also mimics the actions of thyroid hormone," said Wayne. "Because of thyroid hormone's important influence on brain development during gestation, our work holds important implications for general embryonic and fetal development, including in humans."

Researchers have proposed that endocrine-disrupting chemicals may be contributing to the U.S.' rise in premature human births and early onset of puberty over the past couple of decades. "Our data support that hypothesis," said Wayne. "If BPA is impacting a wide variety of animal species, then it's likely to be affecting human health. Our study is the latest to help show this with BPA and now with BPS."

The worrisome results are adding up for BPA and BPS. From Environmental Health News:

Miscarriage risk rises with BPA exposure, study finds

Women exposed to high levels of bisphenol A early in their pregnancy had an 83 percent greater risk of miscarriage than women with the lowest levels, according to new research. The scientists said their new study adds to evidence that low levels of the ubiquitous chemical, used to make polycarbonate plastic and found in some food cans and paper receipts, may affect human reproduction. The study involved 115 pregnant women who had visited a Stanford University fertility clinic within about four weeks of fertilization. The more BPA detected in the women’s blood, the higher their risk of miscarriage, according to the researchers.

“Couples suffering from infertility or recurrent miscarriages would be best advised to reduce BPA exposure because it has the potential to adversely affect fetal development,” wrote the scientists, led by Dr. Ruth Lathi, a Stanford University associate professor of obstetrics and gynecology. 

In 2005, a smaller study in Japan found that 45 women who had three or more first-trimester miscarriages had three times more BPA in their blood than 32 women with no history of pregnancy problems. 

From Science Daily:

BPA increases risk of cancer in human prostate tissue, study shows

Fetal exposure to a commonly used plasticizer found in products such as water bottles, soup can liners and paper receipts, can increase the risk for prostate cancer later in life, according to a study. Exposure of the fetus to BPA in utero is of particular concern, because the chemical, which mimics the hormone estrogen, has been linked to several kinds of cancer, including prostate cancer, in rodent models. The new findings show that human prostate tissue is also susceptible.

"Our research provides the first direct evidence that exposure to BPA during development, at the levels we see in our day-to-day lives, increases the risk for prostate cancer in human prostate tissue," Prins said

This study was done in rats, but thought to also apply to humans. From Science Daily:

Common BPA substitute, BPS, disrupts heart rhythms in females

Bisphenol S (BPS), a common substitute for bisphenol A (BPA) in consumer products, may have similar toxic effects on the heart as previously reported for BPA, a new study finds.

There is implied safety in BPA-free products. The thing is, the BPA analogs -- and BPS is one of them -- have not been tested for safety in humans." "Our findings call into question the safety of BPA-free products containing BPS," he said. "BPS and other BPA analogs need to be evaluated before further use by humans."

The controversy over the safety of BPA (bisphenol A) is still dragging on. However, the new alternatives to BPA may not be any better and may be even worse. To minimize exposure to BPA and other estrogenic chemicals, try to buy and store food in glass bottles, jars, and containers (glass does not contain plastics of any sort). The following two articles discuss this issue. From Nature:

Toxicology: The plastics puzzle

A stroll down the aisles of a US supermarket reveals a modest victory for consumer activism. In the baby-products section, plastic baby bottles, spill-proof cups and miniature cutlery are proudly marked 'BPA-free' — a sign that they no longer contain the compound bisphenol A, found in many plastics.

The partial withdrawal of BPA is the culmination of two decades of research and hundreds of studies linking the compound — which mimics sex hormones called oestrogens — to adverse health effects in rodents and humans.  The decision by regulators in the United States and European Union to ban BPA from baby bottles, combined with industry marketing campaigns, has convinced many consumers that the plastics and other containers currently used to store food are safe.

It is a false sense of security. BPA is still a constituent of many food containers, especially cans. And when companies did abandon BPA, they often adopted compounds — such as the increasingly common bisphenol S (BPS) — that share much of the same chemistry and raise many of the same concerns as BPA. “People use this chemical to replace BPA without sufficient toxicological information,” says Kyungho Choi, an environmental toxicologist at Seoul National University. “That is a problem.”

BPA has formed the chemical backbone of most hard, clear polycarbonate plastic since the 1950s. Over time, studies have linked the chemical — which can leach out of plastics and into food — to a host of adverse health effects, including reductions in fertility and birth weight, male genital abnormalities, altered behavioural development, diabetes, heart disease and obesity1 (see Nature46411221124; 2010).

A few years ago, mounting evidence and concerned consumers convinced governments to take action. In 2011, the European Union banned BPA from baby bottles; the United States followed suit a year later. But BPA-based linings are still slathered on the insides of most food and beverage cans, and used to coat water-supply pipes in many countries. The compound is also found in dental sealants and in incubators for premature infants.

BPA-based epoxy linings are widely used because they are strong, flexible and cheap. They tolerate the high temperatures needed to sterilize foods during canning, and do not interact with a huge array of foods and beverages, according to the North American Metal Packaging Alliance in Washington DC. The alliance estimates that 95% of all aluminium and steel can coatings are epoxy-type resins: more than 99.9% of these contain BPA.

New options are beginning to surface. BPS was first made in 1869 as a dye. But because it was introduced into consumer goods only recently — into cash-register receipts in 2006, for example — few researchers have studied its toxicity. “The main question, to which we have no answer, is: 'is BPS as toxic as BPA?'” says René Habert, an endocrinologist at Paris Diderot University.

The similarity of BPS's structure to that of BPA is enough to raise suspicions that it may mimic oestrogens, says Cheryl Watson, a biochemist at the University of Texas Medical Branch in Galveston. When combined with levels of oestradiol found in adult women, BPS seemed to over-stimulate the pathway, shutting it down and causing cell suicide. The results, says Watson, were typical of those expected of an oestrogen mimic: inappropriate activation of oestrogen responses, disruption of normal oestrogen-response pathways, and eventual cell death. 

Some manufacturers have left the bisphenol family in search of a replacement. In 2007, the Eastman Chemical Company launched Tritan — a new heat-resistant clear plastic — for infant-care products such as baby bottles. This BPA-free plastic has since replaced the old BPA-containing polycarbonate in many water bottles, food containers and children's cups. 

In 2011, George Bittner, a neurobiologist at the University of Texas at Austin and the chief executive of Austin-based chemical-testing company CertiChem, reported that 92% of 102 commercially available plastic products leached chemicals with oestrogenic activity7. This included plastics advertised as BPA-free. The reason, Bittner says, is that additives in plastics — such as stabilizers and lubricants — can also bind to oestrogen receptors, as can some of the plastic monomers themselves. Tritan resins produced by Eastman were among the polymers that showed oestrogenic activity in Bittner's assays. 

In 2012, the world produced some 280 million tonnes of plastic. According to a model based on the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals, more than 50% of these plastics contain ingredients that can be hazardous (see Nature 494169171; 2013). Some are carcinogenic; others are oestrogenic.

It is not yet clear how many of these chemicals are dangerous at the concentrations found in the plastics. But mixed together, the chemicals could have synergistic effects

Ideally, says Watson, the next generation of chemicals would be tested for effects on oestrogen signalling before widespread deployment in food containers.

From Mother Jones:

The Scary New Evidence on BPA-Free Plastics