Announcement

Collapse
No announcement yet.

BPA & metabolic syndrome

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • BPA & metabolic syndrome

    The symptoms of metabolic syndrome sound like a list of the most common health disorders found in the industrialized world -

    Fasting hyperglycemia — diabetes mellitus type 2 or impaired fasting glucose, impaired glucose tolerance, or insulin resistance
    Hypertension AKA high blood pressure
    Central obesity AKA visceral, male-pattern or apple-shaped adiposity - overweight with fat deposits mainly around the waist
    Decreased HDL cholesterol
    Elevated triglycerides

    Link....

    Toxic Plastics: Bisphenol A Linked To Metabolic Syndrome In Human Tissue

    New research from the University of Cincinnati (UC) implicates the primary chemical used to produce hard plastics—bisphenol A (BPA)—as a risk factor for metabolic syndrome and its consequences.

    In a laboratory study, using fresh human fat tissues, the UC team found that BPA suppresses a key hormone, adiponectin, which is responsible for regulating insulin sensitivity in the body and puts people at a substantially higher risk for metabolic syndrome.

    Metabolic syndrome is a combination of risk factors that include lower responsiveness to insulin and higher blood levels of sugar and lipids. According to the American Heart Association, about 25 percent of Americans have metabolic syndrome. Left untreated, the disorder can lead to life-threatening health problems such as coronary artery disease, stroke and type 2 diabetes.

    Nira Ben-Jonathan, PhD, and her team are the first to report scientific evidence on the health effects of BPA at environmentally relevant doses equal to "average" human exposure. Previous studies have primarily focused on animal studies and high doses of BPA.

    They report their findings in the Aug. 14, 2008, online edition of the journal Environmental Health Perspectives. This scientific data comes just before a key Federal Drug Administration meeting about the safety of the chemical in consumer products scheduled for Sept. 16, 2008.

    "People have serious concerns about the potential health effects of BPA. As the scientific evidence continues to mount against the chemical, it should be given serious attention to minimize future harm," says Ben-Jonathan, a professor of cancer and cell biology at UC who has studied BPA for more than 10 years.


    "Experimenting with human tissue is the closest we can come to testing the effects of BPA in humans. It's a very exciting breakthrough because epidemiological studies looking at BPA effects on humans are difficult since most people have already been exposed to it," she adds.

    Scientists estimate that over 80 percent of people tested have measurable BPA in their bloodstream. The UC study was designed to mimic a realistic human exposure (between 0.1 and 10 nanomolar) so that a more direct correlation between human exposure and health effects could be drawn.

    To conduct this study, the UC team collected fresh fat tissue from Cincinnati patients undergoing several types of breast or abdominal surgery. These samples included three types of fat tissue: breast, subcutaneous and visceral (around the organs).
    Tissue was immediately taken to the laboratory and incubated with different concentrations of BPA or estrogen for six hours to observe how the varied amounts of BPA affected adiponectin levels. The effects of BPA were then compared to those of estradiol, a natural form of human estrogen.

    They found that exposing human tissues to BPA levels within the range of common human exposure resulted in suppression of a hormone that protects people from metabolic syndrome.

    "These results are especially powerful because we didn't use a single patient, a single tissue source or a single occurrence," she adds. "We used different fat tissues from multiple patients and got the same negative response to BPA."

    UC's Eric Hugo, PhD, Terry Brandebourg, PhD, Jessica Woo, PhD, J. Wesley Alexander, MD, and Christ Hospital surgeon Jean Loftus, MD, participated in this study. The study was funded by grants from the National Institute of Environmental Health Sciences.
    Last edited by Dr Mordrid; 6 September 2008, 22:18.
    Dr. Mordrid
    ----------------------------
    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  • #2
    More scare tactics?

    Bisphenol A is a white powder with a melting point of about 158°C. Even at 170°, its vapour pressure is only 0.2 mm Hg. It is one of the monomers used primarily in the manufacture of epoxy resins and polycarbonate plastics. It is a known mild toxic and may be a teratogen.

    I'll take epoxy resins, as I know a lot more about them. It is used in a prepolymer reaction with epichlorohydrin in the presence of sodium hydroxide. This produces a thick, syrupy liquid (simplified, this is the base of component A in two-part epoxies you buy in a hardware store). But note, I used the word reaction. This means that the BPA has polymerised and has epoxy groups added. The molecular weight of the polymer has been increased to the range 10,000-20,000 and there is no free BPA or ECH. When you mix this prepolymer with component B, something funny happens, it cross-links between the epoxy groups, changing the linear liquid polymer to a three-dimensional solid one, which is inert, with molecular weights up to 100,000.

    There is therefore zero chance of the public coming across BPA in its raw, unpolymerised state.

    The risk phrases for BPA are:
    # R36 Irritating to eyes.
    # R37 Irritating to respiratory system.
    # R38 Irritating to skin.
    # R43 May cause sensitization by skin contact.
    and the safety phrases are:
    # S24 Avoid contact with skin.
    # S26 In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
    # S37 Wear suitable gloves.
    Nothing very alarming.

    Epoxy resins have been in wide use since the mid-1930s.

    Note that certain grades of epoxy resin is approved for use in contact with foodstuffs.

    Polycarbonates are made from a condensation polymerisation of PMA. It is a hard, naturally transparent, plastic used largely for monitor/TV cases, CDs/DVDs, plastic windows, bullet-proof glass, lenses etc. Again, there is little chance of the public coming in contact with BPA from PC products, EXCEPT there is a minute possibility of polymer reversion in the presence of chlorine (e.g., it is not recommended to use PC kitchenware to hold chlorinated water), although any such dosage would be minimal. BPA has an oral mammalian LD50 in the range of 2000-6500 mg/kg, so massive quantities would have to be released to have acute toxicity effects. It is possible that there are chronic or sub-chronic toxicity effects, sucha as the article describe but the article does mention "high doses" which are unlikely in practice.

    Only one country in the world has decreed that BPA is dangerous to human health and that is Canada, since April of this year.

    I would be much more concerned with TBBPA, tetrabromobisphenol A, which is often mixed with BPA to render epoxy resins and polycarbonates flame-retardant.

    I've worked with BPA and TBBPA in my studies of the electrical properties of epoxy resins. They were chemicals we respected, but we took more precautions with epichlorohydrin which is carcinogenic and volatile.
    Brian (the devil incarnate)

    Comment


    • #3
      With 6 billion pounds of BPA being produced each year it doesn't take much of a leeching rate for it to add up to significant levels in the environment. As such it's found at significant levels in most all humans in industrialized nations.

      Not only Canada but soon Norway will also ban BPA, meaning that by default products headed for Europe will probably lose their BPA as well.

      On the US front Californias Office of Environmental Health Hazard Assessment's Developmental and Reproductive Toxicant Identification Committee is slated to review BPA for addition to its list of reproductive toxins along with several other chemicals. Their recommendation will go to The Governator for approval and addition to the list. The federal government undertook to review BPA in 2007, and determined that there was cause for "some concern."

      Also: a separate international group of 38 experts on BPA recently tied it to numerous disorders including urogenital abnormalities in male babies, metabolic disorder, ADD, ADHD, autism and other neurological disorders.

      Maybe you should have been more careful with it.
      Dr. Mordrid
      ----------------------------
      An elephant is a mouse built to government specifications.

      I carry a gun because I can't throw a rock 1,250 fps

      Comment


      • #4
        Regulatory News
        Aug. 18 - US FDA: Bisphenol A found in plastic bottles is safe
        August 18th, 2008

        From CBC News:

        Despite ongoing safety concerns from parents, consumer groups and politicians, a chemical used in baby bottles, canned food and other items is not dangerous, federal regulators in the U.S. said Friday.

        Food and Drug Administration scientists said the trace amounts of bisphenol A that leach out of food containers are not a threat to infants or adults. The plastic-hardening chemical is used to seal canned food and make shatterproof bottles. It also used in hundreds of household items, ranging from sunglasses to CDs…

        The agency previously declared the chemical safe, but agreed to revisit that opinion after a report by the federal National Toxicology Program said there was “some concern” about its risks in infants. Based on a review of animal studies, the government working group said bisphenol can cause changes in behaviour and the brain, and that it may reduce survival and birth weight in fetuses…

        Canada has announced its intention to ban the use of the chemical in baby bottles. In the spring of 2008, many retailers in Canada said they were ridding their stores of products containing bisphenol A.

        U.S. lawmakers have introduced legislation to ban bisphenol in children’s products.
        Remember, baby feeding bottles are often sterilised with sodium hypochlorite solutions which liberate free chlorine and this is where the potential danger lies. I would say it would be wise to use glass bottles, rather than PC, anyway. But banning BPA or products containing it is not on the cards, with the exception of these, anywhere. Otherwise, it would be back to the Stone Age (I doubt whether there is a single electronics item made without it and no electronics does not bear thinking about! Probably 60-70% of BPA is used in the electronics industry in some form or another.)

        Edit: and PC feeding bottles are no longer available in many European countries, anyway!
        Last edited by Brian Ellis; 7 September 2008, 09:02. Reason: rider
        Brian (the devil incarnate)

        Comment


        • #5
          Sounds like the FDA notice put out about mercury dental fillings about 6 months before the same FDA issued a major warning about their health effects.

          Lesson: politically involved agency pressers are no substitute for peer reviewed papers.
          Dr. Mordrid
          ----------------------------
          An elephant is a mouse built to government specifications.

          I carry a gun because I can't throw a rock 1,250 fps

          Comment

          Working...
          X