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XENOBIOTIC:

discover that plastic food containers and bottles, they release a potentially dangerous to health.


By: Lionel Perez Valenzuela

What are xenobiotics?

originally called xenobiotics (xeno "strange," bio "life), the compounds synthesized in the laboratory and not found in nature. These compounds are generally very stable and non-polar, they tend to accumulate in the tissues of living organisms. Take a long time to degrade in natural systems and can act as pollutants.

are now referred to xenobiotic compounds both natural and synthetic, which are exposed and that our bodies metabolize and accumulate, their effects can be very dangerous to health. Xenobiotics are used in organic chemistry, generally in the industry, plastics, paints, food, medicine, fuel, cosmetics, cigarettes, packaging, etc.. That is, we are constantly exposed to them.

nonpolar compounds generally are lipophilic so, so cross biological membranes easily. . Thus they are unlikely to be excreted as they tend to accumulate in fat. Instead polar compounds can be filtered by the kidneys and excreted much more rapidly.

These xenobiotic compounds, can not be excreted in apolar form, so for disposal is required prior processing in more water-soluble metabolites (biotransformation or metabolism). These reactions of "detoxification" occur mainly in the REL, peroxisomes and mitochondria. In general detoxification reactions occur in two stages:

1 - oxidations, reductions and hydrolysis make the xenobiotic in a more polar metabolite
2 - Conjugation (covalent bond), the xenobiotic or its metabolite with an endogenous molecule polar, for facilitators elimination from the body.

Bisphenol A, a xenobiotic that mimics the action of estrogen.

Bisphenol A (BPA, for its acronym in English) is a component that can be found in all plastics. Initially synthesized in 1891, has been flying a key component in the synthesis of plastics from polycarbonate to polyester. In the U.S. alone produces more than one million tons per year of this compound.

Since 1936 it is known that BPA mimics the estrogen binding to the same receptors as the female steroid hormone. Experiments have shown that this compound may promote tumor cell growth of breast cancer and decrease the amount of sperm.

These findings have led many researchers to wonder about the risks posed to health from the massive use of these plastics that release BPA, especially when used at high temperatures (microwave, washing with hot water), or subjected to heavy use.

Center for Disease Control (CDC) of USA. samples found BPA in nearly all urine samples collected in 2004 in an effort to measure the prevalence (number of individuals in a group or population who have a particular characteristic or event) of various chemicals in the human body.

Studies suggest that BPA does not stay in the body than a few days because it is detoxified as a glucuronide (BPA is associated with glucuronic acid, an acid derivative of glucose), a soluble and easily excreted product. Despite this, the CDC has enontrado BPA-glucuronide in most urine samples, suggesting constant exposure to BPA.

BPA is used in tin cans as a lining to prevent corrosion and contamination of food. It is also used in plastic jars and bottles, so the polycarbonate is transparent and unbreakable. When these bottles and nipples hot water is added and then allowed to cool down the rate of BPA release of these containers increases 55 times.

Recent studies in the journal Reproductive Toxicology suggest that humans may have been exposed to ten times the levels of BPA, deemed safe by environmental enforcement agencies. If it is true that humans metabolize BPA more rapidly than rodents, as suggested by recent studies, then the daily exposure level must be higher to the levels found in human serum samples.

the CDC data have shown that 93% of 2,157 people aged six to eighty-five years show metabolic produce detectable BPA in their urine. The levels are higher in children than in adolescents and adolescents higher than in adults. It has also shown that BPA decreases fertility in female mice, the effects of BPA remain permanent, even after short periods of exposure. Also no need to stay in the body to take effect.

Children and babies more exposed to BPA

is to unborn babies and newborns, where researchers are more concerned, because BPA has been linked with breast cancer and prostate, diabetes and altered menstrual cycles in laboratory mice that were still developing.
Biologists Fred vom Saal and warn that children are exposed to BPA levels ten times higher than those needed to produce the animaels disorders. Especially since the polycarbonate bottles and cans of infant formula BPA freed.

The FDA (Federal Administration Drug USA), first approved by the BPA in 1963, and showed no harmful effects on health. When the U.S. Congress passed a new law in 1976 - The Minutes of Toxic Substances Control-ordering that EPA (Environmental Protection Agency), to conduct or verify safety studies on each new compound chemist before approval for use substances like BPA were already on the market. Despite this, if new evidence emerged about the dangers of BPA or other chemicals, may be new evidence. The problem is that FDA maintains that BPA is safe. Not only that, for the chemical industry, the BPA is not only safe but also very difficult to replace all of its properties: lightweight, unbreakable, inexpensive, and other features are difficult to match.

To further complicate the issue, BPA is not the only chemical compound that mimics the action of estrogens. For example, some compounds in antibacterial soaps, also interfere with hormonal signaling. How they might interact BPA and other chemicals estrogenomiméticos is not known.

Japan and Canada take measures against the use of BPA

Concern about BPA is worldwide and some countries have taken action long ago. In Japan the industry began to use natural resins in place of BPA, especially since Japanese cientiíicos since 1997 showed that BPA was released from polycarbonate bottles. A subsequent study in 1999 showed that levels of BPA in urine were significantly decreased.

Canada has taken the measure of recall of polycarbonate baby bottles, as we read this to RTICLE the daily La Nación:


http://buscador.lanacion.com.ar/Nota.asp?nota_id = bpa = 1006109 & high



Meanwhile in our country, like in the U.S. is likely to take some time before these preventive measures are taken.

What security measures we take to protect our family?

not use bottles or containers made of polycarbonate, are generally transparent or colored and are marked with the number 7, at the base. Also limit or eliminate canned foods: canned, food, soups and infant formula. Can be replaced by similar products in other containers.

If they can not be replaced, never be used in a microwave or storing liquids or hot foods or hot water washing by hand or dishwasher.

You choose whether to use polycarbonate bottles, or old glass bottles. But remember that Bisphenol A is present in those plastic bottles, and a compound which is potentially very dangerous for health and development of babies.