Superfood rice bran contains arsenic

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Superfood rice bran contains arsenic

_http://environment.newscientist.com/article/dn14592-superfood-rice-bran-conta

ins-arsenic.html_

(http://environment.newscientist.com/article/dn14592-superfood-rice-bran-contain\

s-arsenic.html)

 

NewScientist.com news service

Catherine Brahic

Rice bran – a so-called " superfood " – might contain dangerous amounts of a

natural poison.

A new study suggests that rice bran, the shavings left over after brown rice

is polished to produce white rice grains, contains " inappropriate " levels of

arsenic. Andrew Meharg at the University of Aberdeen, UK, and colleagues

found that the levels of arsenic in rice bran products available on the

internet

and used in food-aid programmes funded by the US government would be illegal

in China – the only country in the world to have standards for how much

arsenic is permissible in food.

Meharg's team are calling on the European Union and the US to follow China's

example and update food standards for arsenic.

_Arsenic is a natural carcinogen_

(http://www.newscientist.com/article/dn1300-trace-arsenic-in-water-raises-cancer\

-risk.html) , present in drinking water

around the world including in Australia, the US and _many developing

countries_

(http://environment.newscientist.com/channel/earth/mg18825303.000-bangladeshs-ar\

senic-woes-are-here-to-stay.html) .

In previous work, Meharg has shown that brown rice contains more arsenic

than polished white rice (_Environmental Science and Technology, DOI:

10.1021/es702212p_

(http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/2008/42/i04/abs/es702212p.html)

).

Nutritional drink

In the new study, Meharg and colleagues purchased brown rice from China and

Bangladesh and polished part of it in the same way that it would be to

produce commercial white rice. They found that 1 kilogramme of brown rice

contained

on average 0.76 mg of arsenic in its toxic inorganic form. The rice also

contained some non-toxic, organic arsenic. The polished white rice grains

contained 0.56 mg inorganic arsenic per kg, whereas the rice bran contained 3.3

mg

per kg on average.

On the surface, this appears to be good news: the bran shavings are usually

discarded except in Japan, where they are used in traditional pickling

recipes. But in recent years a number of rice-bran products have come onto US

and

European markets, mainly targeted at health-food consumers. They are labelled

" superfoods " : the bran is high in antioxidants, vitamins, mineral nutrients

and fibre. Producers say it is the largest wasted agricultural food resource

on the planet, with 60 million metric tonnes of it discarded worldwide each

year.

Some companies have produced a powdered version with a long shelf life at

room temperature. Mixed with water, these " rice-bran solubles " make a

nutritional drink and have been distributed as food aid to malnourished

children in

Malawi, Guatemala, Nicaragua and El Salvador. There are plans to further expand

the aid programmes in Latin America, India and the Caribbean.

Meharg and his colleagues purchased nine commercial rice-bran products

online, including rice-bran solubles from NutraCea, a company that participates

in

food-aid programmes, and analysed their arsenic content. The products

contained between 0.48 mg/kg and 1.16 mg/kg of inorganic arsenic. China

recently

updated its standards, and set the limit to 0.15 mg of inorganic arsenic per kg

of food.

Risk analysis

" The arsenic concentrations reported are worrisome, but the risk assessment

is complex, " says Philippe Grandjean, professor of environmental health at

Harvard University's School of Public Health.

Indeed, " safe " standards for arsenic intake are controversial. The risk of

skin, lung, bladder and kidney cancer increases proportionally with arsenic

intake, which has lead toxicologists to the conclusion that there is no " safe "

limit. But risks must be weighed against the benefits gained from drinking

water and eating certain foods that contain the poison.

NutraCea has carried out a pilot project distributing their rice-bran

solubles to 67,000 pre-school children in Guatemala. They monitored the

nutritional

state of 150 children. Whereas at the beginning of the trial, 37% were

deemed malnourished, that dropped to 5% after taking 15 g of the rice bran 5

days

a week for 6 months. The project was funded by the US Agency for

International Development _USAID_ (http://www.usaid.gov/) and the _Christian

Children's

Fund_ (http://www.christianchildrensfund.org/) .

_Marie Vahter_ (http://ki.se/ki/jsp/polopoly.jsp?l=en & d=6103) , an

environmental toxicologist at the Karolinska Institute in Sweden who has done

extensive studies on the health effects of arsenic believes the nutritional

benefits

do not necessarily outweigh the risks, given the availability of other

supplements. " Recent reports indicate increased fetal and infant mortality due

to

fairly low-level arsenic exposure via drinking water, " says Vahter. Arsenic

also impairs brain development and impairs the body’s ability to repair DNA.

Unwanted substances

" Rice-bran solubles are not the only way of getting nutrients to

malnourished children, " argues Meharg. " If aid agencies want to go down the bran

solubles route why not wheat, oat or barely bran solubles. All these crops have

ten

times less total arsenic than rice and are just as nutrient rich. "

" One would expect dietary supplements to be virtually free of unwanted

substances like arsenic, especially when aimed at children, who are

particularly

vulnerable to arsenic, " says Grandjean.

Drinking water limits on arsenic levels are more widespread than food

limits, despite animal studies showing that the body does not distinguish

between

arsenic derived from food and from drink. Water limits tend to be based on the

World Health Organization's " provisional " guideline limit of 0.01 mg of

arsenic per litre of drinking water – although the WHO itself admits that

" based

on health criteria " the guideline would be less than this. It says the value

is restricted by measurement limitations, hence its provisional nature.

According to China's standards, all of the rice-bran products tested by

Meharg would be illegal. According to the UK's 50-year-old standards, two of

the

nine products are safe – yet all can be purchased online in the UK. The US

has no standards for arsenic levels in food, and has a limit of 0.01 mg/l in

drinking water.

" We totally agree with the overall message that it is important to set

standards for inorganic arsenic in our food, " comments Walter Goessler, an

arsenic

expert at the Karl-Franzens University in Austria.

" Rice-bran solubles are being produced by commercial companies who profit

from this commodity, " says Meharg.

At the time of going to publication, NutraCea had not replied to New

Scientist's request for comment.

Journal reference: _Environmental Science and Technology_

(http://pubs.acs.org/journals/esthag/index.html) _(DOI: 10.1021/es801238p)_

(http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/asap/abs/es801238p.html)

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