Ăn gạo lứt rất nhiều
Arsenic (thạch tín,
thuốc độc)
hơn ăn gạo trắng.
Dưới đây là bài phân tích của anh HCD, xin gởi
đến quí vị.
Theo
bản tin từ CNN, thì người Mỹ đang lo ngại ăn gạo sẽ đưa lượng Arsenic (thạch
tín, thuốc độc) vào cơ thể nhiều quá. Theo Consumer Reports thì ít nhất
nó làm cơ thể chứa thêm tới 44%.
Theo cơ quan Phòng Dịch Bịnh Mỹ (Centers for Disease Control), thì nó sinh ra
bịnh ung thư gan, ung thư bàng quang, ung thư phổi.
Bấy lâu nay phe ta ca tụng gạo lứt như là “thần dược” ăn vào bách bịnh tiêu trừ,
nay trong bài báo (có căn cứ từ phòng thí nghiệm) cho thấy ăn gạo lứt thì
mang lượng arsenic vào cơ thể nhiều hơn ăn gạo trắng nhiều. Về phương diện
arsenic thì ăn gạo trắng an toàn hơn.
Các bạn còn nhớ trước đây tôi là làng về Cadmium trong gạo không. Kim loại nầy
cũng gây hại không thưa chi Arsenic. Thái Lan có vùng đồng ruộng Cadmium cao
đến cái độ dân làng bỏ chạy.
Trên đây là tấm hình, nếu các bạn không thấy hình
thì nên dọc attachment.
(-trích-) The Consumer Reports study found that white rice had lower levels of
arsenic compared to brown rice, and that rice grown in Arkansas,
Louisiana, Missouri, and Texas, generally had higher levels of arsenic.(-hết
trích-) (tin nầy đăng trong CNN cách nay vài ngày)
May quá California cũng sản xuất nhiều gạo lắm. Osawha tiên sinh nói nhiều
chuyện không đúng, nhưng với dân Cali thì ông nói đúng câu nầy: “Nên ăn thực
phẩm sản xuất tại địa phương”. Tôi thấy gạo Cali ngon đâu thua gạo
Thái Lan hay gạo Louisiana thề nhưng vì bán rẻ nên bà con ta chê không màng
tới. Bà con ở trong nước có khi quên tường đâu trên thế giới chỉ có vùng Đông
nam Á xuất cảng nhiều gạo. Mỹ cũng xuất cảng gạo nằm trong các quố gia hàng
đầu, trong khi dân Mỹ không ăn hay rất ít ăn gạo.
Arsenic in your
food
Our findings show a real need
for federal standards for this toxin
Consumer Reports
magazine: November 2012
Our
analysis found varying levels of arsenic in more than 60 rices and rice
products.
Organic rice
baby cereal, rice breakfast
cereals, brown rice, white rice—new tests
by Consumer Reports have found that those and other types of rice products on
grocery shelves contain
arsenic, many at worrisome levels.
Arsenic not
only is a potent human carcinogen but also can set up children for other health
problems in later life.
Following our
January investigation, "Arsenic in Your Juice," which
found arsenic in apple and grape juices, we recently tested more than 200
samples of a host of rice products. They included iconic labels and store
brands, organic products and conventional ones; some were aimed at the booming
gluten-free market.
The results of
our tests were even more troubling in some ways than our findings for juice. In
virtually every product tested, we found measurable amounts of total arsenic in
its two forms. We found significant levels of inorganic arsenic, which is a
carcinogen, in almost every product category, along with organic arsenic, which
is less toxic but still of concern. Moreover, the foods we checked are popular
staples, eaten by adults and children alike. See the chart summarizing results of our tests for
arsenic in rice or rice products.
Though rice
isn’t the only dietary source of arsenic—some vegetables, fruits, and even
water can harbor it—the Environmental Protection Agency assumes there is
actually no “safe” level of exposure to inorganic arsenic.
No federal
limit exists for arsenic in most foods, but the standard for drinking water is
10 parts per billion (ppb). Keep in mind: That level is twice the 5 ppb that
the EPA originally proposed and that New Jersey actually established. Using the
5-ppb standard in our study, we found that a single serving of some rices could
give an average adult almost one and a half times the inorganic arsenic he or
she would get from a whole day’s consumption of water, about 1 liter.
We also
discovered that some infant rice cereals, which are often a baby’s first solid
food, had levels of inorganic arsenic at least five times more than has been
found in alternatives such as oatmeal. Given our findings, we suggest limiting
the consumption of rice products. Use our recommendations.
Our study was
a snapshot of the market, with many products purchased in the New York
metropolitan area and online, to gauge the extent of arsenic’s presence in
everyday foods. It can’t be used for overall conclusions about specific brands.
Still, we found important trends:
· White rice
grown in Arkansas, Louisiana, Missouri, and Texas, which account for 76 percent
of domestic rice, generally had higher levels of total arsenic and inorganic
arsenic in our tests than rice samples from elsewhere.
· Within any
single brand of rice we tested, the average total and inorganic arsenic levels
were always higher for brown rice than for white.
· People who ate
rice had arsenic levels that were 44 percent greater than those who had not,
according to our analysis of federal health data. And certain ethnic groups
were more highly affected, including Mexicans, other Hispanics, and a broad
category that includes Asians.
· Reducing
arsenic in food is feasible. We examined the efforts of two food companies,
including Nature's One, trying to
tackle the problem and learned about methods being used to try to reduce
arsenic in products.
· Based on these
findings, our experts are asking the Food and Drug Administration to set limits
for arsenic in rice products and fruit juices as a starting point.
Studies
show that arsenic can cause cancer in humans.
Rice producers
argue that concerns about dietary exposure to arsenic in rice are overblown.
“There is no documented evidence of actual adverse health effects from exposure
to arsenic in U.S.-grown rice,” says Anne Banville, a vice president at the USA
Rice Federation, a trade association representing the $34 billion rice
industry. “And we believe the health benefits of rice must be properly weighed
against the risks of arsenic exposure, which we believe are minimal.”
But scientists
warn of complacency. “We already know that high concentrations of arsenic in
drinking water result in the highest known toxic substance disease risks from
any environmental exposure,” says Allan Smith, M.D., Ph.D., a professor of
epidemiology at the University of California, Berkeley. “So we should not be
arguing to wait for years until we have results of epidemiologic studies at
lower arsenic intake, such as from rice consumption, to take action.” His
studies of arsenic in public water in Chile and Argentina helped show that it
causes lung and bladder cancer and other diseases.
Such long-term
studies that track health effects of exposure to arsenic in rice have only
recently begun in the U.S. Researchers at the Dartmouth Children’s
Environmental Health and Disease Prevention Research Center in late 2011
published a small but informative study that indicated consuming slightly more
than a half-cup of cooked rice per day resulted in a significant increase in
urinary arsenic levels, comparable to the effects of drinking a liter of water
containing the federal maximum of 10 ppb arsenic. The authors say their results
suggest “many people in the U.S. may be exposed to potentially harmful levels
of arsenic through rice consumption.”
The USA Rice
Federation says it is working with the FDA and the EPA as they examine and
assess arsenic levels in food and has supplied rice samples to those agencies
for research. It also says some of its member companies may be doing their own
testing. One rice company shared with us details of how it is taking matters
into its own hands. Grant Lundberg, CEO of Lundberg Family Farms in Richvale,
Calif., which sells rice and rice products, says the company is testing more
than 200 samples of the many varieties of rice in its supply chain and plans to
share the results with FDA scientists.
“We’re
committed to providing safe food, to really listening to our consumers, and
dealing with this problem very openly because doing the research needed to
assess what the risks really are is the only way to go,” Lundberg says.
Tracing the
sources of arsenic
Grant Lundberg, a rice producer in California, has begun
extensive testing for arsenic.
Photo by: Robert
Durell
The USA Rice
Federation tells consumers that there is no reason to be concerned about
arsenic in food. Its website states that arsenic is “a naturally occurring
element in soil and water” and “all plants take up arsenic.”
But “natural”
does not equal safe. Inorganic arsenic, the predominant form of arsenic in most
of the 65 rice products we analyzed, is ranked by the International Agency for
Research on Cancer (IARC) as one of more than 100 substances that are Group 1
carcinogens. It is known to cause bladder, lung, and skin cancer in humans,
with the liver, kidney, and prostate now considered potential targets of
arsenic-induced cancers.
Though arsenic
can enter soil or water due to weathering of arsenic-containing minerals in the
earth, humans are more to blame than Mother Nature for arsenic contamination in
the U.S. today, according to the federal Agency for Toxic Substances and
Disease Registry. The U.S. is the world’s leading user of arsenic, and since
1910 about 1.6 million tons have been used for agricultural and industrial
purposes, about half of it only since the mid-1960s. Residues from the decades
of use of lead-arsenate insecticides linger in agricultural soil today, even
though their use was banned in the 1980s. Other arsenical ingredients in animal
feed to prevent disease and promote growth are still permitted. Moreover,
fertilizer made from poultry waste can contaminate crops with inorganic
arsenic.
Rice is not
the only source of arsenic in food. A 2009-10 study from the EPA estimated that
rice contributes 17 percent of dietary exposure to inorganic arsenic, which
would put it in third place, behind fruits and fruit juices at 18 percent, and
vegetables at 24 percent. A more complete study by the European Food Safety
Authority found cereal products could account for more than half of dietary
exposure to inorganic arsenic, mainly because of rice.
Rice absorbs
arsenic from soil or water much more effectively than most plants. That’s in
part because it is one of the only major crops grown in water-flooded
conditions, which allow arsenic to be more easily taken up by its roots and
stored in the grains. In the U.S. as of 2010, about 15 percent of rice acreage
was in California, 49 percent in Arkansas, and the remainder in Louisiana,
Mississippi, Missouri, and Texas. That south-central region of the country has
a long history of producing cotton, a crop that was heavily treated with
arsenical pesticides for decades in part to combat the boll weevil beetle.
“Extensive
surveys of south central U.S. rice, by more than one research group, have
consistently shown that rice from this region is elevated in inorganic arsenic
compared to other rice-producing regions,” says Andrew Meharg, professor of
biogeochemistry at the University of Aberdeen in Scotland and co-author of the
book “Arsenic & Rice.” “And it does not matter relative to risk whether
that arsenic comes from pesticides or is naturally occurring.” High levels of
arsenic in soil can actually reduce rice yields. Meharg, a leading researcher
in the field, notes the Department of Agriculture has invested in research to
breed types of rice that can withstand arsenic. That may help explain the
relatively high levels of arsenic found in rice from the region, though other
factors such as climate or geology may also play a role.
We tested 223
samples of various rice products that we bought mostly in April and May, many
from stores in the New York metropolitan area and online retailers. The samples
covered a variety of rice-containing food categories, including infant cereals,
hot cereals, ready-to-eat cereals, rice cakes, and rice crackers. We bought
products often used by people on gluten-free or other special diets, including
rice pasta, rice flour, and rice drinks.
We tested at
least three samples of the foods and beverages for total arsenic. We measured
specific levels of inorganic arsenic. And we checked for two forms of organic
arsenic, called DMA and MMA.
Though
inorganic arsenic is considered the most toxic, concerns have been raised about
potential health risks posed by those two organic forms, which the
International Agency for Research on Cancer has labeled “possibly carcinogenic
to humans.” We found DMA in the 32 rices we tested, which include choices from
the south central states and elsewhere, including California, India, and
Thailand.
Within
brands, brown rice had higher arsenic than white.
In brands for
which we tested both a white and a brown rice, the average total and inorganic
arsenic levels were higher in the brown rice than in the white rice of the same
brand in all cases. Among all tested rice, the highest levels of inorganic
arsenic per serving were found in some samples of Martin Long Grain Brown rice,
followed by Della Basmati Brown, Carolina Whole Grain Brown, Jazzmen Louisiana
Aromatic Brown, and Whole Foods’ 365 Everyday Value Long Grain Brown. But we
also found samples of brown rice from Martin and others with inorganic arsenic
levels lower than that in some white rice.
Though brown
rice has nutritional advantages over white rice, it is not surprising that it
might have higher levels of arsenic, which concentrates in the outer layers of
a grain. The process of polishing rice to produce white rice removes those
surface layers, slightly reducing the total arsenic and inorganic arsenic in
the grain.
In brown rice,
only the hull is removed. Arsenic concentrations found in the bran that is
removed during the milling process to produce white rice can be 10 to 20 times
higher than levels found in bulk rice grain.
We also tested
for lead and cadmium, other metals that can taint food. The levels we found
were generally low overall. Based on our recommended limits for rice products,
even the few samples with elevated lead and cadmium should not contribute
significantly to dietary exposure.
Worrisome
arsenic levels were detected in infant cereals, typically consumed between 4
and 12 months of age.
Among the four
infant cereals tested, we found varying levels of arsenic, even in the same
brand. Gerber SmartNourish Organic Brown Rice cereal had one sample with the
highest level of total arsenic in the category at 329 ppb, and another sample
had the lowest total level in this category at 97.7 ppb. It had 0.8 to 1.3 micrograms
of inorganic arsenic per serving.
Earth’s Best
Organic Whole Grain Rice cereal had total arsenic levels ranging from 149 ppb
to 274 ppb, but higher levels of inorganic arsenic per serving, from 1.7 to 2.7
micrograms.
So what’s a
parent to do? To reduce arsenic risks, we recommend that babies eat no more
than 1 serving of infant rice cereal per day on average. And their diets should
include cereals made of wheat, oatmeal, or corn grits, which contain
significantly lower levels of arsenic, according to federal information.
The EPA sets
limits for a carcinogen based on how many extra cases of cancer would be caused
by exposure to the toxin at a certain level. The limit is designed to minimize
that risk. For our recommendations, we used the latest available science to
choose a moderate level of protection that balances safety and feasibility,
similar to the EPA’s approach for water. Our scientists made these calculations
using standard estimates of weight, typical daily consumption of individual
rice products over a lifetime, and the range of levels of inorganic arsenic we
found. For our recommendations for children, we paid particular attention to
their levels of consumption during this critical phase of their development.
According to
federal data, some infants eat up to two to three servings of rice cereal a
day. Eating rice cereal at that rate, with the highest level of inorganic
arsenic we found in our tests, could result in a risk of cancer twice our
acceptable level.
For children
and pregnant women, risks are heightened. Keeve Nachman, Ph.D., a risk
scientist at the Center for a Livable Future in the Johns Hopkins Bloomberg
School of Public Health, says, “The more we learn about arsenic’s additional
effects on the developing brain, the more concerned I am by these levels of
arsenic being found in infant and toddler rice cereal.”
Ready-to-eat
cereals, which are popular with adults as well as children, also gave us cause
for concern. For instance, Barbara’s Brown Rice Crisps had inorganic arsenic
levels that ranged from 5.9 to 6.7 micrograms per serving. Kellogg’s Rice
Krispies, at 2.3 to 2.7 micrograms, had the lowest levels for the category in
our tests.
Rice drinks in
our tests showed inorganic arsenic levels of up to 4.5 micrograms per serving.
Based on those results, our scientists advise that children under the age of 5
should not have rice drinks as part of a daily diet. In the United Kingdom,
children younger than 4½ years are advised against having rice milk because of
arsenic concerns.
“This is a
time when cells are differentiating into organs and many other important
developmental things are going on, so getting exposed to a toxicant like
arsenic in utero or during early childhood can cause damage that may not appear
until decades later,” says Michael Waalkes, laboratory chief at the Division of
the National Toxicology Program. He is one of the authors of a June 2012 report
funded in part by the National Institutes of Health that concluded early life
exposure to arsenic produces a wide range of cancers and other diseases.
Diet changes
arsenic risk
If rice truly
is an important source of arsenic exposure, then people who eat rice should
have greater arsenic levels in their body, on average, than people who do not.
To find out, we analyzed data collected annually by the National Center for
Health Statistics for the National Health and Nutrition Examination Survey
(NHANES). The survey contains information on the health and nutrition of a
nationally representative sample of the U.S. population, based on interviews
and physical exams, which may include blood and urine tests.
Our data
analysis was led by Richard Stahlhut, M.D., M.P.H., an environmental health
researcher at the University of Rochester, who is experienced in NHANES
analysis, and Ana Navas-Acien, M.D., Ph.D., a physician-epidemiologist with
expertise in arsenic research at Johns Hopkins University’s Bloomberg School of
Public Health. Working with Consumer Reports statisticians, they reviewed
NHANES data from 2003 through 2010 from participants age 6 or older whose urine
was tested for arsenic and who had reported what they’d had to eat or drink
from midnight to midnight the day before their examination. A urine test is the
best measure of recent arsenic exposure because most of it is excreted in urine
within a few days after ingestion.
Our
study shows people who eat rice have higher arsenic levels.
Because
seafood contains a form of organic arsenic called arsenobetaine, generally
considered nontoxic to humans, we then excluded from our analysis anyone who
reported eating seafood during the 24-hour period and those with detectable
levels of arsenobetaine in their urine. The remaining participants therefore
were more likely to have had exposure to inorganic arsenic, which poses the
greatest potential health risks.
Our resulting
analysis of 3,633 study participants found that on average, people who reported
eating one rice food item had total urinary arsenic levels 44 percent greater
than those who had not, and people who reported consuming two or more rice
products had levels 70 percent higher than those who had no rice.
“Despite our
taking into account other common sources of arsenic, and no matter which way we
sliced the data, we see a very strong association between rice consumption and
arsenic exposure,” says Stahlhut, who along with Navas-Acien led a similar
analysis of NHANES data for our January 2012 article on arsenic in juice. That
analysis found that study participants who reported drinking apple or grape juice
had total urinary arsenic levels that were on average nearly 20 percent higher
than those who didn’t. Consumers Union, the advocacy arm of Consumer Reports,
urged the FDA to set a 3 ppb limit for total arsenic in apple and grape juice.
“These
findings show that rice is an important source of arsenic exposure for the U.S.
population,” says Navas-Acien. The associations were even stronger for rice
compared with juice and are consistent with the relatively high levels of
arsenic, including inorganic arsenic, measured in rice samples, she says. She
says the results underscore the need for monitoring arsenic in food and
establishing safety standards. A new study of NHANES data from Dartmouth
researchers also shows that rice consumption can contribute to increased
urinary arsenic levels in children.
Consumers
Union believes a standard for arsenic should be set for rice, and industry
should accelerate efforts to reduce arsenic levels in rice. They should also
develop types of rice that take up less arsenic, and use rice with the lowest
possible arsenic in products for young children, such as infant rice cereal.
Our scientists
are also asking regulators to prohibit agricultural practices that may lead to
increases in arsenic in rice:
· The EPA should
phase out use of pesticides containing arsenic.
· The USDA and
the EPA should end the use of arsenic-laden manure as fertilizer.
· The FDA should
ban the feeding of arsenic-containing drugs and animal byproducts to animals.
To find out
more about what Consumers Union is doing on the subject and to get involved, go
toConsumersUnion.org/arsenic.
On the international stage, a group advising the World Health Organization is
meeting in 2014 to consider proposed arsenic standards for rice. Limits of 200
ppb (inorganic) for white rice and 300 ppb (total or inorganic) for brown rice
are under discussion.
After the
concerns raised by our juice story, the FDA says it is confident in the overall
safety of apple juice. “FDA has made significant progress in developing a
proposed action level for arsenic in apple juice and is nearing completion of
this work,” the agency says in a statement.
The FDA also
says it is studying arsenic in rice and rice products to determine the level
and types of arsenic typically found and to identify ways to reduce it.
“The need for
a standard for arsenic in food is long overdue,” says Trudy Bialic, director of
public affairs for PCC Natural Markets, a Seattle-area chain that is America’s
largest food co-op. “Certainly there are excellent and committed people in
FDA’s ranks, but it’s shameful the agency has not addressed this problem more
systematically, leaving us to figure it out on our own to protect ourselves.”
How to cut your
arsenic risk
Test your water. If your home
is not on a public water system, have your water tested for arsenic and lead.
To find a certified lab, contact your local health department or call the
federal Safe Drinking Water Hotline at 800-426-4791.
Change the way you cook rice. You may be able to cut your exposure
to inorganic arsenic in rice by rinsing raw rice thoroughly before cooking,
using a ratio of 6 cups water to 1 cup rice for cooking and draining the excess
water afterward. That is a traditional method of cooking rice in Asia. The
modern technique of cooking rice in water that is entirely absorbed by the
grains has been promoted because it allows rice to retain more of its vitamins
and other nutrients. But even though you may sacrifice some of rice's
nutritional value, research has shown that rinsing and using more water removes
about 30 percent of the rice's inorganic arsenic content.
Eat a varied diet. Some vegetables can accumulate arsenic when
grown in contaminated soil. To help, clean vegetables thoroughly, especially
potato skins. Some fruit juices such as apple and grape juice are high in
arsenic, as our previous tests showed. To prevent obesity and tooth decay,
pediatricians advise that infants younger than 6 months shouldn't drink juice;
children up to age 6 should have no more than 4 to 6 ounces a day and older
children no more than 8 to 12 ounces. Like grape juice, wine also can be a
source of exposure, according to data collected in the FDA's Total Diet Study,
which provides more complete information about arsenic content in a variety of
foods. Go to fda.gov and search
for "total diet study analytical results."
Experiment with other grains. Vary your grains, especially if you
eat more than two or three servings of rice per week. Though not arsenic-free,
wheat and oats tend to have lower levels than rice. And quinoa, millet, and
amaranth are among other options for those on a gluten-free diet, though they
have not been studied as much.
