Hormone Mimics (Endocrine Disruptors): They're in our Food

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> Hormone Mimics (Endocrine Disruptors):

> They're in Our Food

> Should We Worry?

>

> Consumer Reports Jun98

>

> Might chemicals that mimic hormones be harming the

> human endocrine system?

> From top to bottom: the pituitary gland; the thyroid

> and parathyroid glands;

> the adrenal glands atop the kidneys, with the

> pancreas in between; and the

> testes (ovaries, in women). The intestines secrete

> hormones as well.

> There has been a scattering of disturbing news

> reports in the last year or

> so about abnormalities in animals-- male fish with

> female sex organs, for

> instance, and frogs with extra legs. In their search

> for a cause, scientists

> are focusing on a class of chemicals called

> endocrine disrupters. Such

> chemicals seem to interfere with or mimic the action

> of hormones and thus

> may upset the normal growth, behavior, and

> reproduction of wildlife.

>

> If these compounds are harming animals, scientists

> ask, are they harming

> people, too? Some researchers have concluded that

> they might be. In the past

> two years, dozens of conferences have focused on the

> effects of endocrine

> disrupters. The debate will only get louder with the

> expected release this

> summer of the National Academy of Sciences'

> long-awaited report on endocrine

> disrupters. Whatever the report finds, Congress has

> already mandated that,

> by August, the Environmental Protection Agency

> present recommendations for

> screening tens of thousands of chemicals for

> endocrine-disruptive activity

> and limiting human exposure to those that pose a

> problem.

>

> More than a dozen federal agencies and institutes

> are planning nearly 400

> research projects on endocrine disrupters. The

> chemical industry is funding

> studies, too. Are endocrine disrupters something to

> worry about or just

> another false alarm, like those warnings about a

> killer asteroid? Here's

> what scientists know so far, plus our tests of two

> types of product in which

> suspected endocrine disrupters are apt to

> hide--plastic wraps and baby

> foods.

>

> [ See Test of plastic wraps, baby foods below ]

>

> The ABCs of EDs

>

> Some endocrine disrupters, such as dioxins, PCBs,

> and various relatives of

> DDT, are already infamous for the other problems

> they've created. (See

> " Prime Suspects, " on page 55.) PCBs and DDT were

> banned in the U.S. in the

> 1970s, but dioxins are still being released--

> they're byproducts of

> combustion and other processes. All these compounds

> persist at low levels

> virtually everywhere--in air, water, and soil. From

> there, they can enter

> the food chain, working their way into animals and,

> eventually, people.

>

> They accumulate in fatty tissue, from which they are

> released very slowly.

> Other hormone mimics, less well known, are found in

> some plastics. To

> understand how these chemicals work their mischief,

> it helps to know a bit

> about the endocrine system, which has the same basic

> function in animals and

> humans. It's a complex network of glands (the

> thyroid, the ovaries or

> testes, and others) and organ tissues (the

> intestines) that secrete

> hormones. Hormones act as chemical messengers,

> traveling through the

> bloodstream to affect growth, metabolism,

> reproduction, and other functions

> elsewhere in the body.

>

> The endocrine system is finely tuned through

> delicate checks and balances.

> Disrupters can throw off the system by sending the

> wrong signals or blocking

> the right signals. The effect is often temporary in

> adults, whose systems

> are fully developed and fairly stable. Babies and

> small children are more

> vulnerable. And there can be permanent effects on a

> fetus, whose normal

> development requires certain amounts of hormones at

> precise times. Change

> the amount or the timing, and the individual may

> suffer problems in

> behavior, immune function, neurological development,

> or gender development.

> As a link between endocrine disrupters and humans is

> being debated, evidence

> of a connection between disrupters and animals is

> mounting.

>

> Animal evidence

>

> Here are some of the bizarre things that have

> happened to animals:

>

> In a 1981 laboratory study done at the University of

> California, , male

> gulls with a feminized reproductive tract emerged

> from eggs exposed to

> levels of DDT and other synthetic chemicals similar

> to levels found in the

> wild. Similar gender- bending oddities are today

> being found in terns off

> Massachusetts and are likely due, researchers say,

> to as-yet-unidentified

> pollutants.

> In 1992, 12 years after the DDT relative dicofol

> spilled into Florida's Lake

> Apopka, testosterone levels in the lake's male

> alligators were just

> one-quarter to one- half their normal level, and the

> alligators had shrunken

> genitals, according to a research team led by Louis

> Guillette, a University

> of Florida zoologist. What's more, the lake's female

> alligators had

> higher-than-average estrogen levels. " Their eggs

> were weird looking, " says

> Guillette, " and they didn't hatch, or the young died

> within the first two

> weeks. " Guillette's team has found a new abnormality

> in alligators from

> lakes Apopka and Okeechobee--an alteration in

> thyroid hormones, which are

> linked to growth and metabolism. Guillette considers

> the findings important

> because scientists think of alligators as a

> " sentinel " species: Their health

> reflects the health of their ecosystem.

> In 1995, schoolchildren in a nature- studies class

> discovered frogs with

> five legs and other deformities in a pond near

> , Minn. Because

> frogs are another sentinel species, scientists

> around the country took

> notice. Subsequent searches turned up frogs with

> extra or missing legs and

> grossly deformed webbing elsewhere in Minnesota and

> in several other states.

> In Anacortes, Wash., a frog had an eye sprouting

> from behind its front leg.

> Endocrine-disrupting pesticides may be the

> culprit--or, as some researchers

> have suggested, the defects might have resulted from

> exposure to excessive

> amounts of retinoids, vitamin A-like chemicals that

> might have come from a

> natural source like plants in the lake.

> Of Mice--and Men?

>

> Given the similarities between animal and human

> endocrine systems, it's

> tempting to think that what seems to be harming

> animals may harm people. " We

> have to bite the bullet, " says Ana Soto, associate

> professor in cellular

> biology at the Tufts University School of Medicine.

> " Whatever we're finding

> in animals, I think we have to assume that it's very

> relevant to what is

> going on in humans. " Others are much more skeptical.

> " I'm not saying let's

> dismiss everything, " Texas A & M toxicologist

> Safe told our reporter.

> " I'm saying, hey, let's back up. The evidence isn't

> there. Should we do more

> work? Sure, but let's not go bananas. "

>

> mindfully.org note: Safe is an industry sponsored

> scientist, and very

> supportive of industry's point of view.

>

> Indeed, there's no proof yet that routine exposure

> to these chemicals is

> disrupting the human endocrine system. And

> conclusive proof may not come.

> Because people aren't lab rats, researchers may

> never be able to rule out

> other possible explanations for any effects they

> observe. But researchers

> must keep asking questions. Among them:

>

> Do endocrine disrupters affect intelligence?

> When we spoke to scientists and others who believe

> chemicals are disrupting

> the human endocrine system, they often cited the

> work of ph and

> son, psychologists at Wayne State University.

> The sons have been

> tracking the developmental and intellectual

> performance of children whose

> mothers regularly consumed Lake Michigan fish before

> and during pregnancy.

> Those fish contain elevated levels of PCBs and other

> contaminants. In

> September 1996, the sons reported that the

> children of fish-eaters

> showed persistent, measurable intellectual

> impairment. This finding was

> highlighted in " Our Stolen Future, " the 1996

> best-seller that helped kick

> off public interest in endocrine disruption. But

> ph son has drawn

> no conclusion about what particular mechanism might

> have caused the

> impairment. In an interview, he called the idea that

> PCBs disrupted hormone

> function in the brain before birth " pure

> speculation. " Early brain

> development, he said, is " such a complex process,

> and so many things could

> go wrong, that we just don't have any basis for

> concluding that it's

> endocrine related. "

>

> Do endocrine disrupters cause genital birth defects?

> Quite possibly, say researchers at the national

> Centers for Disease Control

> and Prevention. They reported last November that

> hypospadias, a birth defect

> in males in which the urinary opening is

> mislocated--on the underside of the

> penis or even on the scrotum--doubled between 1968

> and 1993, and now

> afflicts nearly 1 of 100 newborn boys nationwide.

> " That makes it the most

> common specific type of birth defect among males, "

> says lead researcher Len

> ozzi.

>

> The defect is thought to result from an inadequate

> surge of the male hormone

> testosterone between 9 and 12 weeks after

> conception. " As you block the

> fetus's own testosterone, the fetus cannot

> masculinize itself, " ozzi

> explains, " and you wind up getting these various

> states of feminization of

> the fetus, of which hypospadias is a mild form. "

> Suspected causes include a

> fungicide and DDE, a breakdown product of DDT. Also

> possible, ozzi says,

> is that doctors have simply become better trained at

> recognizing and

> reporting less severe forms of the defect.

>

> Do endocrine disrupters cause prostate problems?

> Frederick vom Saal, of the University of Missouri,

> Columbia, exposed mouse

> fetuses to tiny doses of the estrogen-like chemical

> bisphenol A, found in

> plastic dental sealants and food- can linings. The

> mice that emerged had

> enlarged prostates overburdened with receptors for

> testosterone as well as

> testes that produced fewer sperm than usual. Based

> on these studies, vom

> Saal hypothesizes that a corresponding overload in

> men could lead to

> increased vulnerability to prostate enlargement and

> perhaps to a decline in

> sperm count.

>

> Do endocrine disrupters lower sperm counts?

> In 1992, Danish endocrinologist Niels Skakkebaek

> determined that sperm

> counts had declined by 50 percent worldwide from

> 1938 to 1990. He later

> suggested that PCBs and pesticides, including DDT,

> may have been the cause.

> But sperm counts are not down everywhere, said Harry

> Fisch of Columbia

> University's College of Physicians and Surgeons in

> 1996. They varied greatly

> in different areas, and hadn't declined at all in 25

> years in the three U.S.

> cities he analyzed.

>

> Yet when Shanna Swan of the California Department of

> Health Services

> recently reanalyzed Skakkebaek's data, adjusting for

> regional variations

> including the type Fisch had found, she discovered

> an even steeper global

> decline. Of all the explanations offered so far,

> Swan says, endocrine

> disruption seems the " most coherent and best

> supported by animal data. " Over

> the next few years, Swan, with researchers in Europe

> and Africa, will be

> analyzing regional differences in semen quality.

> They will compare the sperm

> count of fathers-to-be with their level of sex

> hormones, steroids, and the

> time it took their wives to conceive, a sensitive

> marker of fertility. Stay

> tuned.

>

> Do endocrine disrupters increase the risk of breast

> cancer?

> In 1995, British investigators reported that some

> plasticizers, called

> phthalates, acted as estrogens, enhancing the growth

> of breast-cancer cells

> in lab studies. Two years earlier, Wolff, a

> professor at New York

> City's Mount Sinai School of Medicine, had studied

> 58 women and found that

> the higher the levels of DDE in the blood, the

> greater a woman's risk of

> breast cancer.

>

> But follow-up studies failed to find such strong

> correlation. Last year,

> Wolff teamed up with Harvard researchers to examine

> DDE and PCB levels in a

> larger sample of women. This time, she found no

> evidence that exposure to

> those chemicals increased the risk of breast cancer.

> Now a study has come

> out suggesting an association between PCBs and

> breast cancer--but only for

> women who have never lactated. Wolff's reaction: " I

> don't know. Nature's

> never, never simple. " In search of better data The

> conflicting reports may

> mean that these compounds don't harm people. More

> plausibly, they may mean

> that the scientific tools available are too crude to

> see any harm that's

> there.

>

> Indeed, the several studies that have looked for

> broad, population-wide

> effects have a built-in limitation: Even people in

> remote locations, such as

> Canada's Baffin Island, harbor traces of PCBs, DDT,

> and dioxins. There are

> no unexposed " controls " to help highlight the

> effects of exposure. But

> research, especially on possible effects in humans,

> continues.

>

> Soto of Tufts is joining researchers at the

> University of Granada in Spain

> to develop precise ways to measure patients' blood

> and fat for total

> estrogens, including those originating outside the

> body, such as from

> chemical pesticides and plastics. Her team is

> testing two groups of

> patients--boys with undescended testes and women

> with breast cancer--to see

> whether exposure to environmental estrogens

> correlates with birth defects or

> disease. The National Institutes of Health and the

> Centers for Disease

> Control and Prevention hope to begin clinical tests

> that would help them

> estimate how many Americans harbor traces of

> chemicals that could mimic

> hormones.

>

> What's more, the Chemical Manufacturers Association

> is investing some $4

> million to study endocrine disrupters. " We're taking

> this very seriously, "

> says Jon Holtzman, CMA's vice president for

> communications. " When a

> plausible theory is proposed and consumers are

> depending on the safety of

> the products we produce, we can't walk away. " More

> work lies ahead--rigorous

> research on everything from how endocrine disrupters

> affect individual cells

> to whether they affect groups of people. Because

> science progresses by the

> slow accretion of innumerable facts, a tidy

> explanation is not likely

> anytime soon.

>

> Recommendations

>

> Although research indicates that manmade chemicals

> may be causing problems

> in wildlife, at least in localized areas, it's too

> soon to tell whether

> hormone mimics pose health risks for people. But

> should we ignore warning

> signs and simply hope the news will eventually be

> good?

>

> It makes more sense for government, industry, and

> individuals to take

> reasonable steps to limit exposure. The EPA and

> industry should modify

> processes that release dioxins, for instance, and

> the FDA and industry

> should phase out the use of plasticizers suspected

> of causing endocrine

> problems. Such a phase-out is certainly possible:

> Some plastic wraps already

> contain no plasticizers. If in the face of all that

> is still uncertain, you

> want to reduce your ingestion of the suspect

> compounds, here are several

> low-cost strategies that may help: Consider using

> alternatives to pesticides

> and insecticides on lawn and pets. Wash fruits and

> vegetables thoroughly or,

> better yet, buy organic foods. Limit your ingestion

> of fatty foods (where

> the compounds can accumulate). Heed official

> advisories about fish

> contamination. And if you reheat food wrapped in

> plastic, make sure the wrap

> does not touch the food. The attitude that may serve

> us all best is one of

> prudent caution, not blissful ignorance.

>

>

>

----------------------------------------------------------------------------

> ----

> Tests of plastic wraps, baby foods

> Which suspected endocrine disruptors are in our

> foods, and at what hat

> levels? One category: certain plasticizers, which

> add flexibility to plastic

> food wraps among other products. Plasticizers can

> migrate from wraps into

> foods, especially fatty ones like hamburgers and

> cheese. We tested four

> endocrine disruptors in a variety of plastic

> wraps--both the kind you use at

> home and the kind store-bought foods come wrapped

> in--and in wrapped food.

> We tested a few plastic bowls, too. We also tested

> meat-based baby foods for

> persistent pollutants like dioxins and PCBs.

> Although adult foods are known

> to contain these endocrine disruptors, virtually no

> data have been published

> on amounts in baby foods--an odd data gap,

> considering that exposure during

> infancy could he important.

>

> mindfully.org note: Please note that the chemicals

> found mimic hormones

> which are active in our bodies down to

> concentrations in the

> parts-per-trillion range while the testing done by

> Consumer Reports was at

> parts-per-million.

> That is a difference of six orders of magnitude or

> six zeros.

>

> 1 million = 1,000,000

> 1 trillion = 1,000,000,000,000

> Wraps: Some Mull problem plasticizers

>

> Of seven national and store brands Of plastic wrap

> we analyzed America's

> Choice, Dow brands Saran Wrap, Duane Reade,

> Foodtown, Glad Crystal Clear

> Polyethylene, Reynolds Wrap, and White Rose--only

> Reynolds Wrap and Saran

> Wrap contained any of the five plasticizers we

> looked for.

>

> Would a cooked hamburger that was wrapped in plastic

> Reynolds Wrap or Saran

> Wrap and reheated in a microwave oven absorb

> plasticizers? Yes, a little

> bit, our tests showed, but only where the fat

> contacted the wrap.

>

> It's impossible to say whether a tiny serving of

> plasticizers is risky. If

> you want to play it safe, buy one of the wraps we

> found to be free of

> suspect plasticizers, or buy any polyethylene wrap.

> (Polyethylene lacks

> plasticizers; the product's label should say what

> it's made of.)

>

> In any case, do as some wrap makers recommended and

> leave a gap between wrap

> and food when heating. In fact, that's sound advice

> at any temperature.

> Studies have indicated that some migration of

> plasticizers can occur with

> refrigerated food, too. That's what we found when we

> analyzed 14 national

> and local brands of grocery- store and deli cheese

> wrapped in six types of

> plastic. The wraps themselves had a wide range of

> concentrations of two

> families of problematic plasticizers, adipates and

> phthalates. In the

> cheeses, we found:

>

> Very heavy migration (50 to 160 parts per million)

> of the adipate

> plasticizer DEHA into cheeses in deli cling wrap.

> People who ate several

> ounces of this cheese every day could get doses

> nearly as high as those

> linked to a host of health problems in lab animals.

> Moderate migration (I to 4 parts per million of the

> most common phthalate,

> DEHP, into some of the shrink-wrapped cheeses and

> into two waxed cheeses

> with clear plastic overwrap.

> little to no migration into individually wrapped

> slices of American cheese

> or blocks of cheddar in laminated foil wrap.

> We found no plasticizers at all in eight new

> microwavable Rubbermaid and

> Tupperware bowls.

> Baby foods: No worse than other foods but ...

>

> We tested about 2 dozen meat and poultry baby foods

> made by Gerber,

> Beech-Nut, and Heinz for dioxins, PCBs, and related

> compounds. Like " adult "

> meats, these baby foods contained substantial traces

> of the pollutants. The

> EPA has published what amounts to a limit for dioxin

> exposure. That

> guideline is based on the EPA's definition of a

> negligible cancer risk posed

> by daily intake over a lifetime, not on any

> understanding of the potential

> endocrine-disrupting effects of these chemicals, and

> it does not account for

> the likely need for an extra safety margin to

> protect infants.

>

> Nevertheless, a baby who ate one jar--just 2.5

> ounces--of an average

> meat-based baby food on a given day would consume

> around 100 times the EPA's

> daily limit of dioxins. No brand was significantly

> more contaminated than

> another.

>

> Does that mean babies shouldn't eat meat baby food?

>

> It's not that simple. Other foods babies might eat

> instead--even fruits and

> contain dioxins. Breast milk actually has higher

> levels than meat baby

> food--and because most babies drink 2 pints or more

> of milk a day but eat

> just an ounce or two of processed baby food,

> mother's milk is overwhelmingly

> their largest source of these pollutants.

> mindfully.org note: some studies

> have found that the mother's breast is still the

> best source for milk, and

> that it can reduce the chances of some diseases. In

> spite of the benefits

> still outweighing the risk, this is no reason to

> feel comfortable. Every

> effort should be made to put pressure on our

> regulatory agencies to ensure

> that this vital source of sustenance be made pure as

> it was once just a few

> years ago.

>

> No one would suggest that babies not be breast-fed

> --the benefits of breast

> feeding far outweigh the risk involved. But. that

> doesn't mean the risk is

> nil. It's becoming clear that babies--who, with

> fetuses, are thought to beat

> the highest risk of endocrine-disrupting

> effects--can't avoid consuming rath

> er startlingly high doses of these compounds. The

> health consequences of

> that intake, if any, are unknown. Our results

> suggest why research on

> endocrine disruptors, and expanded efforts to keep

> them out of our foods,

> deserve to be national priorities.

>

>

>

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