Warning about mercury in Tuna may be unwarranted

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Warnings about Mercury in Tuna may be unwarranted

JoAnn Guest Aug 30, 2005 08:33 PDT

 

 

 

 

http://www.medicalnewstoday.com/newssearch.php?newsid=4210

 

Warnings issued to pregnant women of the dangers of eating too much tuna

or swordfish may be unwarranted, say scientists.

 

Research suggests that the amount of harmful mercury in these 'predatory

fish' may have been overestimated.

 

A scientist from the University of Saskatchewan in Canada says that the

mercury may be stored in a less harmful form in the body of the fish.

 

UK experts say that more study is needed before the warning is scrapped.

 

 

Exposure to mercury has been linked with damage to the brain and nervous

system - particularly in the developing foetus, where relatively small

amounts could still be a danger.

 

Predatory fish such as tuna, marlin, shark and swordfish tend to

accumulate in their tissues any mercury in their diet, leading to higher

concentrations of the heavy metal than in other fish.

 

Until now, scientists had thought that the bulk of this was stored in

the form of methyl mercury, which has the potential to be absorbed in

human tissues quite easily.

 

Less toxic?

 

However, the Canadian researchers have found, using a technique called

x-ray absorption spectroscopy, that a great deal of the mercury stored

in fish tissues is in a different form.

 

Rather than bound to hydrogen and carbon atoms, it has formed tight

bonds with sulphur atoms, which, in principle, should make it far harder

for the mercury to be taken up by the human body.

 

This means that it would be potentially less toxic than methyl mercury.

 

Dr Graham George, who carried out the study while based at Stanford

University in the US, said: 'People have used methyl mercury to model

the toxic properties of mercury in fish because they don't know what's

on the mercury in fish tissue.

 

'Now that we know this, we can better investigate its toxic properties.'

 

 

He said that a drug to remove accumulations of mercury from human tissue

was a possibility.

 

More research needed

 

However, Fiona Ford, a nutritionist with the WellBeing Eating for

Pregnancy Helpline, said that it would be premature for mothers-to-be to

disregard the precautionary warnings.

 

At present, women who are planning to conceive, pregnant or

breastfeeding are advised to eat only one or two portions of these fish

a week.

 

She said: 'I would like to see this study repeated - we can't draw firm

conclusions from the results of just one study.

 

'It would be very good if women were told that they could eat larger

quantities of this type of fish.

 

'Tuna, in particular, is very affordable and contains large quantities

of essential fatty acids which are very good for baby brain

development.'

 

The study was published in the journal Science.

 

The WellBeing helpline can be reached on 0845 130 3646 between 10am and

4pm Monday to Friday.

_________________

 

 

JoAnn Guest

mrsjo-

www.geocities.com/mrsjoguest/Diets

 

 

 

 

AIM Barleygreen

" Wisdom of the Past, Food of the Future "

 

http://www.geocities.com/mrsjoguest/Diets.html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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