iThyroid.com

PHTHALATES

Phthalates are chemicals used to make plastics flexible and they have been implicated in causing premature breast development in girls, which is a condition called thelarche. There has been an epidemic of thelarche on the island of Puerto Rico for the last two decades where affected girls begin breast development between the ages of 6 and 24 months. Researchers have finally concluded that the cause is phthalates. There is some indication that phthalates may also affect thyroid function.

Panel Expresses Concern About DEHP, A Plasticizer, As Used In Medical Devices For Ill Newborns

After a 15-month review of safety data on seven phthalates, or plasticizers -- the chemicals used to give plastics such characteristics as flexibility and strength -- an expert panel set up by the NIEHS/NTP’s Center for the Evaluation of Risks on Human Reproduction, has expressed “serious concern” about the use of one of the chemicals, DEHP, to make polyvinyl chloride (PVC) medical tubing and other medical devices for feeding and medicating critically ill newborn infants. Panel members said they hoped their finding would spur industry to find a substitute material but that, at this time, DEHP-derived PVC tubing continues to be needed to support preemies and other ill newborns through life-and-death situations.

The panel, which was formed of outside and government experts, including several from the National Institute of Environmental Health Sciences and the National Toxicology Program and a chair from the Environmental Protection Agency, said DEHP could leach from continuously used tubing in sufficient amount to possibly affect the development of the male infant’s reproductive system. DEHP is no longer used in toys intended for mouthing - nipples, teethers, pacifiers, rattles - by U.S. manufacturers. Soft PVC teething toys have also been banned by the European Union.

The panel, working over a 15-month period, reviewed data on seven plasticizers and generally found “minimal” or “negligible” concerns about the others. A backgrounder on the panel’s work is available at http://ntp-server.niehs.nih.gov/htdocs/liason/CERHRPhthalatesAnnct.html

The following study shows that long-term (3 months) treatment of rats with phthalates causes "changes are consistent with persistent hyperactivity in the gland." What this means is that exposure of foods or waters to flexible plastics (water containers, plastic wrap, etc.) could be a cause of hyperthyroidism. Also, note that fat lowering drugs like clofibrate and fenofibrate can have the same effects.

 

Toxicol Lett 1988 Jan;40(1):37-46

Alterations in the thyroids of rats treated for long periods with di-(2-ethylhexyl) phthalate or with hypolipidaemic agents.

Price SC, Chescoe D, Grasso P, Wright M, Hinton RH

Robens Institute of Industrial and Environmental Health and Safety, University of Surrey, Guildford, U.K.

Treatment of rats for periods of 3 months or longer with the hypolipidaemic drugs clofibrate and fenofibrate or with the plasticiser di-(2-ethylhexyl) phthalate causes alterations in the thyroid. The colloid is shrunken and contains calcium-rich inclusions. Electron microscopy shows increases in the number and size of lysosomes, hypertrophy of the Golgi apparatus and dilation of the rough endoplasmic reticulum. These changes are consistent with persistent hyperactivity in the gland.

 

Environ Health Perspect 1986 Dec;70:195-210

Effects of phthalic acid esters on the liver and thyroid.

Hinton RH, Mitchell FE, Mann A, Chescoe D, Price SC, Nunn A, Grasso P, Bridges JW

The effects, over periods from 3 days to 9 months of administration, of diets containing di-2-ethylhexyl phthalate are very similar to those observed in rats administered diets containing hypolipidemic drugs such as clofibrate. Changes occur in a characteristic order commencing with alterations in the distribution of lipid within the liver, quickly followed by proliferation of hepatic peroxisomes and induction of the specialized P-450 isoenzyme(s) catalyzing omega oxidation of fatty acids. There follows a phase of mild liver damage indicated by induction of glucose-6-phosphatase activity and a loss of glycogen, eventually leading to the formation of enlarged lysosomes through autophagy and the accumulation of lipofuscin. Associated changes are found in the kidney and thyroid. The renal changes are limited to the proximal convoluted tubules and are generally similar to changes found in the liver. The effects on the thyroid are more marked. Although the levels of thyroxine in plasma fail to about half normal values, serum triiodothyronine remains close to normal values while the appearance of the thyroid varies, very marked hyperactivity being noted 7 days after commencement of treatment, this is less marked at 14 days, but even after 9 months treatment there is clear cut evidence for hyperactivity with colloid changes which indicate this has persisted for some time. Straight chain analogs of di-2-ethylhexyl phthalate, di-n-hexyl phthalate and di-n-oxtyl phthalate differ entirely in their short-term effects on the liver and kidney but have similar effects on the thyroid. The short-term in vivo hepatic effects of the three phthalate esters can be reproduced in hepatocytes in tissue culture. All three phthalate esters, as well as clofibrate, have early marked effects on the metabolism of fatty acids in isolated hepatocytes. The nature of these changes is such as to increase storage of lipid in the liver. A hypothesis is presented to explain the progress from these initial metabolic effects to the final formation of liver tumors.

 

Comp Biochem Physiol C Pharmacol Toxicol Endocrinol 1995 Jun;111(2):317-23

Hypolipidemic agents alter hepatic mitochondrial respiration in vitro.

Chance DS, McIntosh MK

Department of Food, Nutrition, and Food Service Management, University of North Carolina at Greensboro 27412, USA.

The direct effects of three different classes of structurally diverse hypolipidemic agents on respiration were studied in mitochondria isolated from donor Sprague-Dawley rats. Two classes of peroxisome proliferators (i.e. plasticizers and hypolipidemic hormones and drugs) and one class of peroxisome inhibitors (i.e. anti-psychotic drugs) were studied. The phthalate ester plasticizers dibutylphthalate, ethylhexanoic acid and di(2-ethylhexyl) adipate, the hypolipidemic hormones or drugs dehydro-epiandrosterone (DHEA), thyroxine (T4), triiodothyronine (T3), gemfibrozil, clofibrate and naphthoflavone, and the anti-psychotic drugs chlorpromazine, thioridazine and fluphenazine were studied. As the dose of the plasticizer dibutylphthalate increased from 8 to 200 mumol/l, there was a decrease (P < 0.05) in state 3 (+ADP) respiration and in the respiratory control ratio for both substrates tested. The anti-psychotic drug chlorpromazine decreased state 3 malate + pyruvate-supported respiration and increased state 3 succinate-supported respiration. As the concentration of all three anti-psychotic drugs increased, there was a linear increase in state 4 respiration (-ADP) and a decrease in the respiratory control ratio for both substrates tested. As the dose of the hypolipidemic agents DHEA, gemfibrozil and T4 increased, there was a linear reduction in state 3 malate + pyruvate-supported respiration. However, when succinate was used as the substrate to support respiration, only the thyroid hormones significantly decreased state 3 respiration. Gemfibrozil, T4 and T3 increased state 4 respiration, regardless of the substrate used. As the dose of clofibrate, gemfibrozil, and the thyroid hormones increased, there was a linear reduction in the respiratory control ratio for both substrates tested.

Nail Polish and Other Cosmetics May Cause Infertility

From Dr. Mercola's website, mercola.com

"Women of reproductive age (20-40 years) were found to have significantly higher levels of monobutyl phthalate, a reproductive and developmental toxicant in rodents, than other age/gender groups. From a public health perspective, these data provide evidence that phthalate exposure is both higher and more common than previously suspected," the CDC investigators wrote.

The investigators also speculated that the higher levels in women of reproductive age were due to the use of cosmetics such as perfume, nail polishes, and hair sprays. The extensive use of these products among women is probably leading to the inhalation and absorption of this chemical through the lungs, the investigators said.

The report from the Environmental Working Group (EWG) (LINK) entitled "Beauty Secrets" suggests that the substance may be responsible for the following problems, which have increased during the 1970s and '80s:

• Declining sperm counts

The EWG says that getting any immediate regulatory action passed is virtually impossible, due to the fact that the associations are difficult to impossible to prove. Under the current regulations, the responsibility of proving that there is a public health threat from cosmetics primarily falls upon US health authorities rather than the manufacturers.

Phthalate Plasticizers Dangerous, Especially to Children

Many of the chemicals in various plastics, especially PVC, can be harmful to children, according to several new reports. Certain chemicals known as phthalates are used as plasticizers, which serve to make the plastic more flexible. Below are 2 recent studies showing dangers of 2 different types of phthalates.

DEHP

Although research is currently ongoing on the toxicity of plasticizers that are commonly blended with PVC products, Italian researchers fear that they may pose a danger to babies.

In a recently published review of existing studies, Dr. Giuseppe Latini, a Pediatrician, notes some interesting points concerning the most common plasticizer, di-(2-ethylhexyl)-phthalate (DEHP):

• Many plastic items are made of polyvinylchloride (PVC) blended with plasticizers, with DEHP being the most frequently used.

• It has been detected in water, soil and food and is therefore considered as a widespread environmental contaminant.

• Over the past several years, a number of publications concerning toxic effects of DEHP on animals and humans have been reported.

Dr. Latini notes that "long-term exposure, especially in human beings at risk such as pregnant women and children, requires more in-depth studies."

He concludes that if future studies confirm the dangers of DEHP, "it would be advisable in the future to replace current PVC plasticizers, especially if they come into contact with babies, with better-quality materials."

BBP

DEHP is not the only plasticizer or phthalate to show toxic effects. Butyl benzyl phthalate (BBP), another plasticizer, has been shown to have estrogenic qualities, have toxic effects on the testicles, and to cause birth defects.

Now, researchers from Japan have found that the toxic effects of BBP exposure can extend into the next generation, at least in lab animals.

Investigators found that oral doses of BBP in rats had the following effects:

In the parent animals:

• Increase in kidney weight in rats (both sexes)

In the offspring:

• Decreased body weight

Biology of the Neonate November, 2000; 78; 269-276 and Reproductive Toxicology 2000 Nov 1; 14: 513-532

DR. MERCOLA'S COMMENT: The effects of these chemicals on the endocrine system, particularly during pregnancy, breastfeeding and childhood are very disturbing. I would strongly disagree with the author of the first study who says that if future studies confirm the dangers of these plasticizers, that they should be replaced by safer substances.

It is criminal to wait for further results while people continue to be exposed. The precautionary principle dictates that pregnant women and babies should not be exposed to substances unless they have been shown to be essentially safe. The burden of proof should be on the manufacturers of these chemicals to PROVE that they are safe and should NOT be on scientists to prove that it is toxic.

About a year ago the European Union (EU) has banned phthalates from toys intended for children under 3 years of age (Lancet, Dec 11, 1999).