October 14, 2010
And this is when I am proud to be Canadian!
"Our science indicated that Bisphenol A may be harmful to both human health and the environment and we were the first country to take bold action in the interest of Canadians,” said Leona Aglukkaq, Minister of Health.
"96. Phenol, 4,4′ -(1-methylethylidene)bis-, which has the molecular formula C15H16O2"
"A scientific assessment of the impact of human and environmental exposure to bisphenol A has determined that this substance constitutes or may constitute a danger to human health and the environment as per the criteria set out under section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999, also referred to as “the Act”)."
July 27, 2010
BPA is found in high levels on grocery register receipts
September 16, 2008
Every day new information is coming to light regarding the effects of BPA, found in the plastics we use in our food. Today's health messages contained the following:
Rochester study raises new questions about controversial plastics chemical
A University of Rochester Medical Center study challenges common assumptions about the chemical bisphenol A (BPA), by showing that in some people, surprisingly high levels remain in the body even after fasting for as long as 24 hours. The finding suggests that BPA exposure may come from non-food sources, or that BPA is not rapidly metabolized, or both.
The journal Environmental Health Perspectives published the research online January 28, 2009.
"Common Chemical Linked to Metabolic and Cardiovascular Disorders
Exposure to a chemical commonly used in food packaging materials may be putting millions at an increased risk for cardiovascular disorders, diabetes, and liver abnormalities, researchers here said. "
Previously accumulated information relating more to pets can be found in the following:
BPA is primarily used to make polycarbonate plastic food and beverage containers, plastic food wrap, and epoxy resins that are used to line metal cans for food, such as cans of soup. Polycarbonate plastic food and beverage containers that contain BPA will be labeled recycling symbol #7. However, not all recycling symbol #7 containers will be made with BPA.
Bisphenol-A when combined with insulin causes body cells to develop into fat cells:
"The presence of BPA during the same period caused a 150% increase in the TG content, a 60% increase in the LPL activity, and a 500% increase in the GPDH activity. Thus, BPA by itself can trigger 3T3-L1 fibroblasts to differentiate into adipocytes. Next, the confluent cultures were treated with BPA for 2 days and subsequently treated with a combination of INS and BPA for 9 days. The simultaneous presence of BPA with INS caused a 370% increase in the TG content, a 200% increase in the LPL activity, and a 225% increase in the GPDH activity compared with the cultures treated with INS alone."
"The researchers tested BPA’s effect on glucose regulation by measuring glucose and insulin levels in adult male mice treated with BPA injections, then comparing them with levels in mice treated with E2 and a control group treated with corn oil. BPA caused oversecretion of insulin in mice at a dose of 10 micrograms per kilogram body weight per day (μg/kg/day) via a rapid mechanism, taking only 15 to 30 minutes. Treatment over a course of four days with 100 μg/kg/day induced the insulin resistance that precedes type 2 diabetes. E2 had the same effects at the same doses. Glucose metabolism remained stable in the control rats."
Determination of bisphenol A in canned pet foods.
"The concentration of BPA ranged from 13 to 136 ng/g in canned cat food and from 11 to 206 ng/g in dog food. Also, to confirm that the BPA had originated from the can coating, distilled water was added to each washed empty can and the cans were autoclaved at 121 degrees C for 30 min. The concentration of BPA leached from empty cans was between 7 and 31 ng/ml."
While there have been rumblings in the nutritional forest around bishpenol-A possibly causing problems for a number of life forms, what hasn't been approached in the past is the effect upon genetic coding, and the result for future generations. New reports are starting to emerge, such as the following report on epigenic influence:
In August 2007, Duke University researcher Randy Jirtle and his team, published research in the journal PNAS, the Proceedings of the National Academy of Sciences focusing on bisphenol-A, a common chemical in polycarbonate plastic.
"It's everywhere," Jirtle said. "It's in most hard plastics, clear plastics, like the containers your water comes in. It's used inside food cans. It's in dental sealants, adhesives - everywhere."
The chemical is already known to cause epigenetic changes. In his work, Jirtle exposed female mice to the chemical and later bred them. The mothers seemed unaffected, but their pups all later became obese, had fertility problems and either prostate or breast cancer.
Some of the other rumblings that have been around for a longer period of time are the following:
Bisphenol-A is a hormone-disrupting chemical considered to be potentially harmful to human health and the environment. It has been known that scratched and worn polycarbonate feeding bottles will leach this chemical into liquids.
Concerns about day to day health for the present generation:
Scientific studies show that:· Phthalates can interfere with the natural functioning of the hormone system.· Phthalates can cause reproductive and genital defects.· Exposure is linked to premature birth and early onset of puberty.· Phthalates may lower sperm count and are associated with the risk factors for testicular cancer.· Phthalates are linked to allergies and asthma.· Exposure may be linked to liver and kidney damage.· Exposure can also interfere with the normal development of a fetus.
The chemical bisphenol A (BPA), widely used in products such as food cans, milk container linings, water pipes and even dental sealants, has now been found to disrupt important effects of estrogen in the developing brain.
Endocrine Disrupters inhibit human thyroid peroxidase activity
These results indicate effects of ED on endocrine regulatory circuits apart form the reproductive axis, namely interference with thyroid hormone biosynthesis on the level of iodide organification. Inhibition of TPO activity might thus contribute to the goitrogenic action reported for some of the ED.
Consumption of Commercial Canned Food and Risk of Hyperthyroidism in Cats
The consumption of canned cat food has been implicated in three epidemiologic studies on factors associated with the incidence of feline hyperthyroidism. In each the duration and exclusiveness of consumption of canned cat food was not reported.
The rumblings around thyroid disease have gone on for a few of years, now. The following is a report from 2001:
Journal of the American Veterinary Medical Association in March of 2004 shows some interesting information. There is a strong correlation between eating canned food and developing hyperthyroidism later in life; in fact, cats who eat only canned foods from "pop-top" type cans have five times the risk of developing hyperthryoidism relative to cats who eat only dry food. Cats whose diet is 50% canned food have 3.5 times the risk of developing hyperthyroidism relative to cats who eat only dry food. It has been speculated that pop-top type aluminum cans are lined with a substance called Bisphenol-A-diglycidyl ether, which is transferred into food containing oils or fats. In areas of the world where this type of can is not used for cat food, hyperthyroidism is not a common disease.
And echoed by the AVMA in 2004:
Results—Age-specific hospital prevalence of feline hyperthyroidism increased significantly from 1978 to 1997. Overall, consumption of pop-top canned (vs dry) food at various times throughout life and each additional year of age were associated with greater risk of developing hyperthyroidism. In female cats, increased risk was associated with consumption of food packaged in pop-top cans or in combinations of pop-top and non-pop-top cans. In male cats, increased risk was associated with consumption of food packaged in pop-top cans and age.
The above report is expanded in Marvistavet:
"A recent study published in the Journal of the American Veterinary Medical Association in March of 2004 shows some some interesting information. There is a strong correlation between eating canned food and developing hyperthyroidism later in life; in fact, cats who eat only canned foods from “pop-top” type cans have five times the risk of developing hyperthyroidism relative to cats who eat only dry food. Cats whose diet is 50% canned food have 3.5 times the risk of developing hyperthyroidism relative to cats who eat only dry food. It has been speculated that pop-top type aluminum cans are lined with a substance called Bisphenol-A-diglyciddyl ether, which is transferred into food containing oils or fats. In areas of the world where this type of can is not used for cat food, hyperthyroid is not a common disease. Still, it is important to realize that a good 25% of hyperthyroid cats have never eaten canned foods in their lives, so there is clearly more than one factor at work."
It is interesting to read above that Marvistavet is attributing the leaching to the fat content. According to dry matter calculations, canned foods have a disproportionate amount of fat content as the ingredients used are not usually rendered to remove that fat, prior to being included in the product.
Screening for Potential Goitrogenic Effects of Phenolic Compounds in Cat Food Using a Model Iodide Organification System
"Hyperthyroidism is the most frequently diagnosed endocrine disorder in cats, with one in 300 cats developing the disorder. The most common symptoms of feline hyperthyroidism are weight loss, polyphagia, unkempt haircoat, polyuria/polydipsia, vomiting, hyperactivity, and increased fecal volume. Between 97-99% of cats with hyperthyroidism have autonomous functional adenomas of the thyroid. Seventy percent have bilateral adenomas. Because there is no isthmus connecting the two lobes of the thyroid in the feline, the bilateral nature in the majority of cases is significant, indicating that a major factor of developing hyperthyroidism could be nutritional or environmental."
The site above goes on to suggest a theory that other compounds addressed lower down on this page may also have some involvement:
"In unpublished work from our laboratory, several anti-oxidant compounds found in commercial cat food were identified as having potential goitrogenic effects in an in vitro iodide organification assay. These compounds include butylated hydroxyanisole (BHA), with its metabolite, tert-butyl hydroquinone (TBHQ), and ethoxyquin (EQ). Furthermore, several studies have identified isoflavones, present in commercial pet foods that use soy beans as a protein source, as influencing serum thyroid hormone levels. Eating canned food has been associated with a higher risk of developing feline hyperthyroidism. Bisphenol-A (BPA) is a plasticizing compound used to line the inside of the metal cans containing pet food and will be evaluated for its ability to influence iodination."
Endocrine Disrupting Chemicals and diabetes: insights from experimental toxicological studies. Alberto Mantovani and Francesca Baldi, Dept. of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Rome - Italy. Endocrine Disrupting Chemicals (EDCs) have been given big attention from scientific community because of their involvement in female and male infertility and related diseases. However an increasing number of data suggest how some EDCs may have a role also in the so-called "metabolic syndrome" and, in particular, in type 2 diabetes. In such field, experimental toxicological studies may supply a remarkable contribution, by either supporting the biological plausibility of epidemiological hypoteses or identifying new EDCs potentially involved.
Bisphenol A, an estrogenic EDC, causes hyperinsulinemia and interferes with cell activity in rat, although further data are needed to study this possible association.
"Many present laboratory animal studies suggest that bisphenol A exposure at very low doses is
linked to a staggering number of health problems, including prostate and breast cancer, obesity,
hyperactivity, diabetes, altered immune system, lowered sperm count and sperm defects, increase in aggression, elimination of sex differences in behavior, impaired learning and memory, and early puberty."
Here there is a suggestion that the influence of BPA is irreversible during formative years, but can be reversed if the recipient is adult before exposure:
Insulin resistance and diabetes are believed to be linked to exposure to EDCs, as are neurological problems such as Attention Deficit Hyperactivity Disorder. According to the report, "the disruptive effects of developmental exposure are permanent and irreversible." Adult exposures, it says, result in measurable but reversible effects.
Governments are starting to take note where humans are concerned, and yet no consideration is being given to our pets who are sometimes fed a 100% pop top can diet:
"We concluded the margin of safety is most at risk with newborns," Clement said. Chemical studies on animals have linked BPA to cancer and infertility.
The National Toxicology Program is coming out with new information on Bisphenol A from time to time. My concern around studies related to tolerance levels supposedly have been done by removing food from cans and testing the cans with water in them to determine leaching. Fat content in foods is going to retain and transfer more of the BPA from food cans than water will, so these tests are drastically undervaluing the amount of toxicity involved in foods containing high fat content such as the cat foods being pushed by some veterinarians influenced by the latest circulating fad.
There is a study being published in December 2009's Consumer Reports regarding BPA content in a variety of commercial food items, listed here.