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May 12, 2004
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This was taken from a post in another forum and I thought it pertinent to post here:

As we move into the summer, it's important to use sun protection of the best kind. According to Dr. Pickart at Skin Biology in Seattle, WA, what we've been led to believe about sunscreens may be what's aggravating other areas of health concerns.

For more info please see (see chapters 9 and 9.1 also)

Estrogenic sunscreen chemicals might explain most

of the social changes in California over the past 30 years."

A California customer

Toxic Estrogenic Chemical Sunscreens

Even worse for your health is the fact that many common free radical generating sunscreen chemicals also have estrogen like-effects. Such effects can increase cancers, cause birth defects in children, lower sperm counts and penis size in men, plus a plethora of other medical problems. These effects are similar to many banned chemicals such as DDT, Dioxin, PCBs.

Estrogenic chemicals can mimic hormonal (or real) estrogen, the key female sex hormone. When the body's hormone receptors recognize the estrogenic chemical as estrogen, the result is feminization of the tissue.

Some of these effects may be more subtle than physical abnormalities and may manifest themselves as behavioral changes (Fox et al. 1978), such as aberrant behavior of birds during nesting, which can have significant effects on their nesting success.

Government regulations require that new chemicals pass screening tests to determine that they do not cause cancer. But no rules yet require similar testing of chemicals for effects on reproductive hormones.

Common Estrogenic Toxins Estrogenic Toxins Intended Uses

DDT (Dichloro, diphenyl, trichloroethane) Insecticide, especially for mosquitoes

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin and similar chemicals) Chemical by-product during manufacturing of insecticides and plastics

PCBs (Polychlorinated Biphenyls) Insulating oil for electrical transformers

2,4-D Broadleaf weed killer

Diethylstilbestrol (DES) A potent synthetic estrogen

Chemical Sunscreens Blocking ultraviolet rays on human skin


Expected Effects of Estrogenic Chemicals in Humans In Women Endometriosis


Severe PMS

Erratic Periods

Increased Breast and Uterine Cancer

Fibrocystic breast disease

Uterine cysts

In Men Lowered Sperm Counts

Sexual Indentity Confusion - Feminization

Breast Enlargement

Smaller then normal penis size

More testicular cancer

Undescended testicles

Block or reduce fetal imprinting of male behavior pattern in brain


Discovery of Gender-Bending Estrogenic Chemicals in the Environment

In the 1950s, the effect of estrogenic toxins such as DDT was linked to eggshell thinning in many bird species. Chemicals with estrogen-like actions can also cause severe developmental problems such as turning fish into hermaphrodites. Over the past 50 years, studies on estrogenic toxins have greatly expanded our knowledge of these effect - some of which is detailed below.

Many hormone affecting chemicals remain in widespread use. 2,4-D, and similar products, are largest-selling broadleaf herbicides in North America and some 60 million pounds of such chemicals are applied annually in the USA alone. Three widely used pesticides are estrogenic: dieldrin, toxaphene, and endosulfan. While dieldrin and toxaphene have been banned, endosulfan remains the USA's most heavily used pesticide.

Not all environmental gender-benders are estrogenic. Benomyl, a fungicide used on crops such as rice, tomatoes, apples, and grapes, has toxic actions on the testes where it causes the premature release of cells that would have become sperm.

Also, the greatest increases in human cancers over the last 30 years have been those of the breast, ovaries, testes, and prostate, all tissues that are sensitive to sex hormones.

Many Common Sunscreen Chemicals are Strong Estrogens

Margaret Schlumpf and her colleagues (Institute of Pharmacology and Toxicology, University of Zurich, Switzerland) have found that many widely-used sunscreen chemicals mimic the effects of estrogen and trigger developmental abnormalities in rats. (Schlumpf , Margaret; Beata Cotton, Marianne Conscience, Vreni Haller, Beate Steinmann, Walter Lichtensteiger. In vitro and in vivo estrogenicity of UV screens. Environmental Health Perspectives Vol. 109 (March 2001) pp 239-244)

Her group tested six common chemicals that are used in sunscreens, lipsticks and facial cosmetics. Five of the six tested chemicals (benzophenone-3, homosalate, 4-methyl-benzylidene camphor (4-MBC), octyl-methoxycinnamate and octyl-dimethyl-PABA) behaved like strong estrogen in lab tests and caused cancer cells to grow more rapidly.

Uterine growth and endometriosis

One very common sunscreen chemical, 4-MBC, was mixed with olive oil and applied to rat skin. This caused a doubling of the rate of uterine growth well before puberty. "That was scary, because we used concentrations that are in the range allowed in sunscreens," said Schlumpf. Three of the six caused developmental abnormalities in animals. The major cause of sterility in women in the USA is endometriosis, a condition afflicting 5.5% of American women. Exposure to excessive estrogen, that may have come from such sunscreens, is felt to be the primary cause of endometriosis.

Breast milk

Schlumpf's group also found estrogenic sunscreens in the breast milk of mothers at levels of nanograms per kilogram of fat. This is the about same level as other known environmental contaminants such as PCBs. Schlumpf commented that this exposure could be dramatically increased in childhood by the large amount of sunscreen used by bathers, especially children. Her group is following the offspring of 4-MBC exposed rats to see if they develop health problems.

Based on these results, the Swiss researchers concluded that the impact of sunscreens containing these "endocrine disruptors" should be investigated more closely, in particular their penetration through human skin.


Estrogenic Synergies May Multiply Toxic Effects

Combinations of estrogenic sunscreens and other pollutants may act together to intensify their effects. Researchers at Tulane University in New Orleans believe that a mixture of estrogenic toxins -- such as sunscreens, PCBs, DDT, etc., are more harmful if mixed together. The Tulane researchers found one mixture of estrogenic toxins to be 160 to 1600 times more toxic than the individual chemicals in the mixture.

Gender-Bending Effects are Most Severe During Early Development

Current evidence points to early development (embryo, fetus, juvenile) as the time when children's organs are the most sensitive to estrogen exposure and developmental abnormalities. However, some effects may not become apparent until later in life, when normal sexual maturity is expected.

The basic human form is female. Early in fetal development, the genes must signal if a fetus is to be male. The secretion of male hormones is the signal that activates genes that cause male development. If this does not happen, the human has female imprinting - regardless of whether the person's cells have male (XY) or female genes (XX). If a mother has been exposed to a natural estrogen or estrogenic toxin during the crucial period when genes normally activate masculine patterns, the seventh and 14th weeks of pregnancy, then there is not the proper switching from female to male. If the estrogenic toxins only appear sporadically (such as when the mother uses an estrogenic sunscreen, the disruptions may not trigger a complete reversal of a male's gender,

but may exert subtle physical (such a reduced penis size) and mental changes (such as sex role confusion) that become apparent later in life. Conversely, if a synthetic compound blocks estrogen actions, this can produce the sex organs of a male in a fetus that is genetically female.

After using chemical sunscreens, a pregnant woman mother may unwittingly pass some hormone-mimicking pollutants to her child before birth through her placental blood supply and via her breast milk with which she later feeds her newborn.

Some currently used pesticides have been found to interfere with male development, producing undescended testes, nipples on males, hypospadias, decreased sperm counts, and altered mating behavior. When a widely used insecticide, methoxychlor, was fed at low doses to pregnant mice, it caused permanent increases in prostate weight in male offspring of females.

Endocrine disruptors can affect male/female sex ratio in Daphnia (a water flea).

Feminized Male Alligators

Male alligators exposed to pesticides in Florida have difficulty reproducing, partly because their penises are not developing to normal size. Effects attributed to estrogenic environmental toxins have produced male American alligators with underdeveloped sex organs and vitellogenin (an egg and yolk protein normally found only in females) in male animals.

Also, alligator eggs exposed to DDT or another pesticide, dicofol, hatch male alligators that grow penises only one-third to one-half normal size, and fail to breed.

In addition, males of of many other wildlife species in the same areas of Florida (birds, fish, amphibians, and mammals) are being "feminized" by exposure to low levels of pesticides and other toxic chemicals released into the environment.

Florida Panthers

The Florida panther, an endangered species, is failing to reproduce itself. There are only 30 to 50 panthers remaining, and the reason for the decline has postulated to an effect of environmental estrogens. Between 1985 and 1990, 67 percent of male panthers were born with one or more undescended testicles (cryptorchidism). Some Florida panthers are sterile and many others produce abnormal or deformed sperm.

Loss of Libido in Men

Estrogenic chemicals block testosterone actions. This can reduce sexual arousal and sensation and contribute the a loss of libido.

Symptoms of excessive estrogen in women

In women, excessive estrogen and estrogen-like chemicals produce intensified estrogen effects on the body.

Excessive estrogen:

1. Affects your fluid balance, so that swelling due to fluid retention may become noticeable. It can causes elevations of blood pressure, headaches, and migraines.

2. Has a stimulating effect on breast tissue but excess estrogen can also increase fibrocystic breast disease and painful breast swelling.

3. Suppresses thyroid hormone production and this may cause fatigue plus aches and pains in muscles and joints.

4. Stimulates the appetite, makes you crave sweets, leads to weight gain from fat as well as fluid.

5. Intensifies PMS symptoms and produce a mental feeling of being edgy and nervous. Insomnia is also a common side effect.

6. Increases your chances of developing emdometriosis, breast cancer, and uterine cancer.

(An updated review of environmental estrogen and androgen mimics and antagonists. Sonnenschein C, Soto AM. J Steroid Biochem Mol Biol 1998 Apr;65(1-6)143-50)


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