Shampoo Ingredient Kills Rats' Brain Cells

[Guest guest]

[industry spokesmen ALWAYS say a given chemical/poison is safe, and keep

denying harm until the very end. GO NATURAL.]

 

Health

Shampoo Ingredient Kills Rats' Brain Cells

http://www.forbes.com/lifestyle/health/feeds/hscout/2004/12/06/hscout522699.html

 

By Steven Reinberg

HealthDay Reporter

 

MONDAY, Dec. 6 2004 (HealthDayNews) -- Experiments with the brain cells of

rats show that contact with an ingredient found in shampoos, hand lotions

and paint causes neurons to die.

 

The chemical, methylisothiazolinone (MIT), belongs to a class of compounds

called biocides. These are used in the manufacture of many common household

products and industrial water cooling systems to prevent bacteria from

developing.

 

According to the National Institutes of Health, brands containing MIT

include the shampoos Head and Shoulders, Suave, and Clairol, as well as

Pantene hair conditioner and Revlon hair color.

 

" As far as I can tell, no neurodevelopmental testing has been done on MIT, "

said lead researcher Elias Aizenman, a professor of neurobiology at the

University of Pittsburgh School of Medicine.

 

Aizenman said he is concerned that without such testing it is not known if,

for example, a pregnant woman who is exposed to MIT could put her fetus at

risk for abnormal brain development. People working directly with MIT are

those most at risk, he said.

 

In earlier experiments with rat brain cells, Aizenman's team found that

direct exposure to MIT in concentrations like those found in hand cream was

enough to kill neurons. In the current series of experiments, also with rat

cells, the researchers found that a long exposure to low concentrations of

MIT caused a malfunction in the ways neurons communicate with each other.

 

" One of the things that this compound was very good at was preventing

neurons from communicating with other neurons, " he said.

 

Aizenman presented his findings Dec. 5 at the American Society for Cell

Biology annual meeting in Washington, D.C.

 

Whether long-term exposure to products containing MIT is dangerous is not

known, Aizenman said. " Can I say that these products are safe to use? No, "

he said. " Can I say that these products are unsafe to use? No. "

 

Aizenman believes that testing needs to be done to determine if MIT is

harmful to humans in the concentrations found in household products.

 

" It appears that the Environmental Protection Agency [EPA] does not require

neurodevelopmental testing, " Aizenman said. " That is bothersome. Maybe

there are substances that have made it into general use that could be

damaging to the nervous system. Regulators need to take a hard look this

and require more tests. "

 

The work that Aizenman has been doing " is important in understanding the

things that people are exposed to on a chronic, daily basis, " said Beth Ann

McLaughlin, an assistant professor of pharmacology at Vanderbilt University.

 

McLaughlin added that people using products containing MIT should be

skeptical. " There is a healthy dose of skepticism that needs to come when

using any products or being intensely exposed to any compound, " she said.

 

" These findings are expected, " said Gerald McEwen, vice president for

science at the Cosmetic, Toiletry and Fragrance Association. " MIT is a

biocide. The purpose of it is to kill bacteria. You would expect it to be

detrimental to any type of cells. "

 

McEwen said that direct exposure to high concentrations of MIT will be

irritating to the skin, because it can damage skin cells. However, he

doesn't believe that MIT poses any dangers to consumers in the low

concentrations found in household products.

 

" The ability of MIT to cause neurotoxicity has been studied, " McEwen said.

In animals exposed to MIT, there has been no hint of neuro-damage, because

MIT affects only the cells it touches and there is no way for it to get

into the bloodstream and go to the brain, he said.

 

" It can't get to your brain cells, period, " he emphasized.

 

MIT has been approved as a biocide by the EPA, which looked at the

neurological effects, McEwen added. This information was published by the

Cosmetic Ingredient Review, an industry program that reviews the safety of

cosmetic ingredients, he explained.

 

However, McLaughlin remains concerned. " The quantity of compounds that we

can make that make the quality of life wonderful, in the short term, is

growing, " she said. " But we are lagging in our understanding of what those

compounds can do to our health and our children's health. "

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Shampoo 'risk to unborn babies'

Last Updated: Monday, 6 December, 2004, 10:47 GMT

http://news.bbc.co.uk/1/hi/health/4071401.stm

 

Some shampoo contains a chemical that kills off bacteria

A chemical found in shampoo and hand lotions may damage the developing

nervous system, research suggests.

 

A US study found methylisothiazolinone (MIT) can affect the growth of parts

of developing nerve cells which help them communicate with their neighbours.

 

The work, by the University of Pittsburgh, was carried out in rats, but

researchers are concerned about the potential effect on human foetuses.

 

Details were presented to the American Society for Cell Biology.

 

 

Cell signalling structures

Axons: an extension from the cell body used for sending signals to other cells

Dendrites: Elaborate projections on the cells that receive incoming information

Researcher Dr Elias Aizenman said: " While more research is needed to

determine what effect MIT would have in rodent models, both at the cellular

level and to a developing nervous system, our results thus far suggest

there is a potential that everyday exposure to the chemical could also be

harmful to humans.

 

" I would be particularly concerned about occupational exposure in pregnant

women and the possibility of risk to the foetus. "

 

Widely used

 

MIT is used to kill harmful bacteria that like to grow near moisture or water.

 

It is often used in personal care products like shampoos and hand lotions -

but also in water cooling systems and in factories which need water for

manufacturing.

 

However, Dr Aizenman said he had been unable to find any reports about the

effect of the compound on the nervous system.

 

His team is now planning more research to help understand how MIT affects

the development of cells.

 

The latest study found prolonged exposure to low levels of the chemical

inhibited the development of nerve cell structures called dendrites and

axons, which play key roles in enabling one cell to transmit signals to its

neighbours.

 

MIT apparently blocked the function of an enzyme that is activated when

cells come into contact with each other.

 

Dr Aizenman said: " This chemical is being used more and more extensively,

yet there have been no neurotoxicity studies in humans to indicate what

kind and at what level exposure is safe.

 

" I realise it's a big leap to suggest there may be a parallel between

environmental exposure and the noticeably higher rates of diagnosed

childhood developmental disabilities, but I would caution that based on our

data, there very well could be neurodevelopmental consequences from MIT. "

 

Industry assurance

 

Dr Chris Flower, of the Cosmetics, Toiletries and Perfumery Association in

the UK, said MIT had passed numerous safety tests and would continue to be

used in a wide range of products.

 

He said: " There is no cause for concern. MIT has passed all the safety

tests for use in these products. "

 

Dr Flower said MIT was only used in combination with certain other

chemicals in products in Europe.

 

But he said the European Commission's independent expert scientific

committee had reviewed all the data on MIT and concluded it was also safe

to use on its own, with limits set on the maximum concentration.

 

Dr Flower said because MIT was a preservative, if it was introduced into

certain cells in the lab it was bound to affect their growth in certain

concentrations.

 

But he said the chemical had a good safety profile for the toiletries and

cosmetics which people regularly used.