Birth Weight Raises More Questions on Seafood Safety
Women who eat too much shellfish before
pregnancy, particularly crabs and lobsters, may increase their
chance of having babies who are small for their gestational
age
(SGA), report French scientists in an article posted online 24
October 2007 ahead of print in Environmental
Health. Eating fish, however, seems
to have the opposite effect. The findings further fuel the
debate over how much and what types of fish and other seafood
are beneficial to would-be moms.
"Some studies suggest the omega-3
fatty acids in fish and seafood are beneficial to fetal growth
and birth weight," explains first author Laurence
Guldner, an epidemiologist at the National Institute of Health
and Medical Research, University of Rennes, "but others
report no benefit or even a negative effect." The new
report could help explain these discrepancies, because the
results distinguish between the effects of fish and shellfish, and
between even more specific subcategories of
seafood—something most earlier work did not do.
The study included 2,398
pregnant women in Brittany, France, who were part of the Pélagie
cohort assembled to investigate effects of environmental pollutants
on
pregnancy, birth outcomes, and child health and development.
The researchers gathered information on consumption in the year
prior to pregnancy of saltwater fish (e.g., salmon), mollusks
(e.g., oysters), large crustaceans (e.g., lobster), and small
crustaceans (e.g., shrimp).
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Eat now, pay later? Although it's
too soon to put the kibosh on lobster, a seafood study suggests
that high crustacean
consumption may be linked to low birth weight.
image: LibbyH/Creative Commons
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Statistical analysis, adjusted for a number
of potential confounders, showed that women who ate 2 or more
meals of shellfish per week had a statistically significant
2.14 greater likelihood of having an SGA baby (defined as
having birth weight below the tenth percentile for a given
gestational age and sex) compared with those who ate shellfish
less than once per month. Those who ate fish 2 or more times
per week were about half as likely to have an SGA baby than
those who ate it less than once per month (a nonsignificant
finding).
"Most of the negative effect of
seafood on SGA was [associated with] eating large crustaceans,
like crabs and lobsters," explains Guldner. He suggests
that high tissue concentrations of persistent organic
pollutants such as dioxins and polychlorinated biphenyls
accumulated by these animals may cancel out the potential
beneficial effect of their omega-3 fatty acids.
Indeed, the results of some other studies
have suggested that low-level exposure in utero to
such pollutants may have a negative effect on birth weight. However,
the evidence to date is inconclusive.
"Unfortunately, no distinction was
made between the fish types eaten [in this study],"
cautions Thorhallur Ingi Halldorsson, a researcher at the State
Serum Institute in Copenhagen, Denmark. "We should
[therefore] be careful in promoting fish as beneficial for
fetal growth. Oily fish is a good source of omega-3 fatty
acids, but high consumption can lead to higher body burdens of
organic pollutants, which might affect growth." Halldorsson
adds that regular consumption of varying fish types should therefore
be encouraged.
Rosa Ortega, a professor
of nutrition at the Complutense University of Madrid, Spain,
adds, "It
would certainly be a good idea for women to make sure their
seafood comes from guaranteed clean waters. But with everything
in moderation, a new mother-to-be is probably still safe to
satisfy her craving for a lobster dinner."
Adrian Burton
New Yardstick for Medicinal Plant Harvests
Every year more than 400,000
tons of medicinal and aromatic plants from approximately 3,000
species
are traded internationally, according to TRAFFIC, a nonprofit
watchdog
group that monitors commerce in natural products. (Up to 70,000
species are used medicinally worldwide, most of them locally.) Such
a growth in demand for these plants threatens natural
resources, since about 80% of commercially traded species are
gathered from the wild, according to the World Conservation
Union (IUCN). In February 2007, several groups concerned about
potential adverse effects of this rise on plant habitats
announced an international standard designed to preserve
nature's medicine chest for future generations. A year
later, the standard appears to be bearing fruit.
The IUCN Medicinal Plant
Specialist Group, IUCN Canada, the German Federal Agency for
Nature Conservation,
WWF Germany, and TRAFFIC proposed the standard and coordinated
several rounds of international vetting in 2005 and 2006. The
new International Standard for Sustainable Wild Collection of
Medicinal and Aromatic Plants (ISSC-MAP) is intended to balance
the needs of people whose traditions and livelihood depend on
these species with the plants’ long-term survival in
their native habitats.
The new standard is based
on six principles related to maintaining wild resources, preventing
negative environmental impacts, respecting customary rights
(for example, of indigenous populations), and exercising
responsible management and business practices. Plant scientists
also drew on earlier guidelines both for the conservation of
medicinal plants and for good agricultural and collection
practices. "We did not want to reinvent the wheel,"
says Susanne Honnef, TRAFFIC medicinal plant officer with WWF
Germany, "so the standard builds on existing
frameworks."
The new standard involves
all actors along the supply chain—from wild plant harvesters to
sellers—in a process for determining how to sustainably
conduct harvests and trade, says Honnef. The standard also
outlines practices for monitoring the impact of harvests over
time.
Honnef says the standard will protect
important natural resources. As the benefits of sustainable use
become more broadly recognized, harvesters will be encouraged
to protect the ecosystems that support their livelihoods. And
government agencies will have tools for defining benchmarks
in
a trade that is often informal and that falls through the
cracks between groups that manage agriculture and forestry.
The standard was tested in preliminary
trials undertaken in six countries. Over 6 months in 2007, for
example, 2 Indian communities used the standard to gauge
population health of 6 commercially traded species, says
Giridhar Kinhal, special projects coordinator for Foundation
for Revitalisation of Local Health Traditions, a nonprofit
scientific and research organization in Bangalore. Based on
that trial, says Kinhal, the communities saw improved
regeneration of the studied plant populations, but also
reported the need for further guidance in assimilating these
outcomes into resource management. Next comes a 2-year
implementation phase at sites in Asia, Africa, southeast
Europe, and South America.
Danna Leaman, chair of
the IUCN Medicinal Plant Specialist Group and a member of the
advisory group that
guided the development of ISSC-MAP, says, "A concrete
activity like this is a real step forward" for the IUCN,
which has worked for years to engage industry in biodiversity
protection. Indeed, ISSC-MAP goes even further than current
guidance such as Fair Trade and Organic certification.
For example, it has been
up to individual inspectors to determine whether a wild collection
operation
meets the requirements for Organic certification. Josef Brinckmann,
vice president for research with manufacturer Traditional
Medicinals, says that although the wild botanicals they use
qualify for Organic certification, some sites will need further
work to conform with all 6 principles of the ISSC-MAP. "Many of these certified Organic wild collection sites
would need a few years to make the necessary changes for
conformance with the ISSC-MAP standard," he says. Yet,
Brinckmann adds, the extra work will be worthwhile if
compliance with the standard can help a company demonstrate
unequivocably that its operations help maintain the botanical
resource.
Brinckmann points
to Asia and Europe as places where the standard may first have
a significant impact
in alleviating intense harvest pressures. "China and India
are the two largest producers and exporters of medicinal plants
in the world," he notes. Southeastern European countries
and Russia are also important in the world market.
David A. Taylor
Do Bacteria Promote Asthma?
Newborns whose lungs become colonized with
certain bacteria are more likely to develop wheezing and
childhood asthma than babies not colonized by the bacteria.
This connection, reported in the 11 October 2007 issue of the New England Journal of Medicine, raises the possibility that controlling bacterial
colonization in neonates may lower the prevalence of childhood
asthma.
Pediatrician Hans Bisgaard,
director of the Danish Pediatric Asthma Center at Copenhagen
University
Hospital, and colleagues studied 321 asthmatic mothers and
their infants for five years. "By including mothers with
asthma, we identified a high-risk cohort where we expect to see
more children with asthma," says Bisgaard. A family
history of asthma raises the risk for childhood asthma.
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image: Clockwise from top: CDC/PHIL; James O'Conner; Janice Carr/CDC/PHIL
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At 1 month and 12 months of age, the
babies were tested for Streptococcus
pneumoniae, Haemophilus influenzae, Moraxella catarrhalis,
and Staphylococcus aureus. The first three pathogens cause pneumonia,
whereas S. aureus commonly infects the skin. Parents recorded the
children's respiratory symptoms, such as wheezing and
persistent cough, in daily diaries. Physicians examined the
children for asthma when they reached 5 years of age.
One-fifth of newborns were colonized with S. pneumoniae, H. influenzae, M. catarrhalis, or
some combination thereof, and the presence of 1 or more of
these microbes was associated with a 2.4 times greater risk of
persistent wheeze and a 3.85 times greater risk of
hospitalization for wheezing. Moreover, babies harboring any of
these bacteria were about 3 times as likely as children without
them to develop asthma by age 5 years. The presence of S. aureus was
not linked to wheezing or asthma, nor was this bacterium found
to colonize the airways of any of the children at age 12
months.
During the first month
of life, "children genetically disposed to asthma may be
inefficient at clearing pathogenic bacteria from the
airways," proposes Bisgaard as an explanation of his
observations. Neonates' immature immune systems may also
be more susceptible to bacterial damage that initiates
inflammation leading to asthma, he says. Bisgaard plans to
treat a future group of pregnant women and neonates with
probiotics (potentially beneficial bacteria) to assess whether
such therapy prevents childhood asthma.
"The study raises good questions
about immune imbalance associated with asthma," says
Stanley Szefler, head of pediatric clinical pharmacology at the
National Jewish Medical and Research Center in Denver. However,
he notes, "the positive cultures may be due to an immune
imbalance shortly after birth that could lead to bacterial
colonization, yet the bacteria [themselves] may not be the
direct cause of asthma." An editorial in the same issue
of the New England Journal of
Medicine makes
a similar point—the Danish researchers may have discovered a
"new sentinel" for the development of asthma rather
than a "causative signal," writes Erika von Mutius,
a professor of pediatrics at the University of Munich.
Carol Potera
Expert Panel Weighs In on Global Cancer Control
Cancer originates
in genetic mutations, but diet, activity level, and other
lifestyle factors play a critical role in determining whether
these mutations
occur, making cancer a largely preventable disease. This is
among the main conclusions of Food,
Nutrition, Physical Activity, and the Prevention of Cancer: A
Global Perspective, released in
November 2007 by the World Cancer Research Fund (WCRF)
International and the American Institute for Cancer Research
(AICR).
WCRF International/AICR
commissioned 9 systematic literature review (SLR) teams comprising
22
panelists to summarize the literature on nutrition, physical
activity, and cancer. The teams examined 7,000 articles,
reviews, and meta-analyses in all languages. Team findings went
to an international panel that synthesized information for many
different cancers to come up with the report's main
recommendations.
The report lays out a cogent groundwork
for understanding how diet, exercise, and other lifestyle
factors affect cancer risk, as well as how to use this
information for more effective cancer prevention on a global
scale. The public policy implications of the recommendations
will be the subject of a further report to be published in
late
2008.
Report Recommendations for Reducing Cancer Risk |
- Be as lean as possible without becoming
underweight.
- Be physically active for at least 30 minutes
every day.
- Avoid sugary drinks. Limit consumption
of energy-dense foods (particularly
processed foods high in added sugar, low
in fiber, or high in fat).
- Eat a variety of vegetables, fruits, whole
grains, and legumes such as beans.
- Limit consumption of red meats (such as
beef, pork, and lamb), and avoid
processed meats.
- Limit alcoholic drinks to 2 a day for men
and 1 a day for women.
- Limit consumption of salty foods and
sodium-processed foods.
- Don't use supplements to protect against
cancer.
- Mothers should breastfeed exclusively for
up to 6 months before adding other
liquids and foods.
- After treatment, cancer survivors should
follow these recommendations for cancer
prevention.
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The report concluded that about 40% of all
cancers are linked to poor diet, physical inactivity, and
suboptimal body weight. The panelists recommend maintaining a
body mass index of between 21 and 23 (until now, the standard
recommended range has been 18.5 to 24.5), exercising
moderately, and limiting consumption of alcohol, high-fat
foods, and refined carbohydrates such as sugary beverages. In
addition to increasing vegetable intake, the report suggests
replacing red meats and processed meats with poultry, fish,
and
eggs.
"The conclusions are really not
surprising, but what did surprise me was the universality of
the recommendations across so many countries," says Tim
Byers, a preventive medicine professor at the University of
Colorado Cancer Center in Aurora. "I was surprised to
find that nutritional factors that can lower cancer risk are
shared widely across the world. . . . The importance of this
report, therefore, is both that it is comprehensive and also
that it is global."
An earlier WCRF International/AICR
report, published in 1997, stated that "cancer is principally
caused by environmental factors, of which the most important
are tobacco, diet and factors related to diet, including body
mass and physical activity, and exposures in the workplace and
elsewhere." Although the panel still emphasizes the
importance of not smoking and avoiding secondhand smoke, this
report concentrated on the impacts of diet, activity, and
weight.
Lawrence H. Kushi, associate
director for etiology and prevention research at Kaiser Permanente
in
Oakland, California, and an SLR team co-leader, says this
document is a substantial improvement over the first report in
that it is more comprehensive. Moreover, he says the report is "groundbreaking
[because] it established methodologies for conducting literature
reviews and meta-analyses for
observational epidemiologic data."
Indeed, Kushi notes that
the systematic review process relied primarily on analytical
epidemiologic
studies, such as prospective cohort studies and
case–control studies. "Consistency of findings
across these more rigorous study designs and [well-defined]
populations form the bulk of the report and the basis of its
recommendations," he says.
Compelling evidence for
the impact of environmental factors comes from studies describing
changes in
the rates of different cancers in populations that migrate from
one country to another. For example, research in the 1980s
showed that breast cancer incidence increased almost 3-fold in
first-generation Japanese women who migrated to Hawaii, and up
to 5-fold in the second generation. The migrant studies "prove that the main determinants of cancer patterns are
environmental, and suggest that patterns of food, nutrition,
and physical activity are important among these causes," the
report states.
"One of the project's major
strengths was the participation of many leaders in the field,
from the development of the methodology, to the conduct of the
SLRs, to issuing conclusions regarding the evidence and public
health recommendations," says SLR team leader Elisa
Bandera, an epidemiologist at UMDNJ–Robert Wood Johnson
Medical School and The Cancer Institute of New Jersey.
"This is a very important resource for cancer prevention
and public health education. It can guide researchers in
identifying research gaps quickly, and ultimately should help
guide public policy changes as well." Moreover, she
notes, WCRF International/AICR will update the evidence on its
website as new findings emerge. For more information, go to
http://www.dietandcancerreport.org/.
M. Nathaniel Mead
EHPnet: Healthy House Institute
The mission
of the Boise, Idaho–based Healthy House Institute (HHI)
is to educate homeowners on ways to make and keep their home
environments as
healthful as possible. Toward this end, the HHI has compiled
data in areas including indoor air, drinking water, building
and remodeling, housekeeping, and energy efficiency on its
website,
http://www.healthyhouseinstitute.com/.
Information is presented
in seven topic categories: Air, Building, Design, Energy, Health & Safety,
Materials & Furnishings, and Water. Each topic page
presents resources organized by four information types:
Reviews; Tools; Articles, Hints, & Tips; and Books & Videos.
The Reviews category links to overviews of products inspected
by HHI that perform well in such areas as safety,
energy use, allergen reduction, and use of chemicals. The Tools
category lists products that can be used in building or
remodeling to make a healthier home. These include paints and
coatings, lighting fixtures, indoor air cleaners, and pest
control strategies.
The Articles,
Hints, & Tips section
provides information on new green products, how to choose
sustainably produced building materials, green roofs, and
energy efficiency. The Books & Videos page lists
educational materials such as Green
Building A to Z (an introduction to
sustainable housing), Green Clean (a primer on eco-friendly housekeeping),
and The Mold Survival Guide (which offers advice on eradicating
mold while minimizing health risks). Visitors can also consult
the "HHI-pedia," a
list of definitions for terms used in green building and housekeeping.
Erin E. Dooley
The Beat
edited by Erin E. Dooley
GreenChill Partnership
Several U.S. supermarket chains have
teamed up with the EPA and the refrigerant and refrigeration
industries in a voluntary program to curb emissions that can
exacerbate climate change. The GreenChill Advanced
Refrigeration Partnership seeks to reduce refrigerant emissions
over regulatory requirements as well as assess the performance
of new refrigeration technologies. The 10 supermarket partners
have also committed to use only ozone-friendly refrigerant
alternatives and technologies in all their new and remodeled
stores. Besides the environmental payoff, the EPA estimates
these efforts will save the markets more than $12 million each
year in increased energy efficiency and reduced operating
expenses.
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Nonsmokers Benefit from Bans
Hundreds of municipalities across the
United States have enacted some form of public smoking ban. Now
a first-of-its-kind study published in Volume 37, Issue 3
(2007) of the Journal of Drug
Education has looked at how
these bans affect the health of nonsmokers. Results from 2
Indiana counties showed that hospital admissions for heart
attacks among nonsmokers with no risk factors for heart disease
dropped 70% within 22 months of a smoking ban going into
effect. Admissions for heart attacks among smokers didn't
change, however. Secondhand smoke causes blood vessels to
constrict and reduces the amount of oxygen that can be
transported in the bloodstream.
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Malawi Fights Aflatoxins
Malawi is
home to several efforts to help farmers rid their peanut crops
of aflatoxins—waste
products of Aspergillus molds that grow on improperly stored
crops. Once a chief export, Malawian peanuts are now banned in
the
European Union because of the threat of aflatoxin
contamination. An NGO known as the Food and Chemical Safety
Environmental Action Team is educating Malawian farmers on
safety measures, including better grain sorting and storage
methods. The National Smallholder Farmers' Association
of Malawi also is helping farmers meet aflatoxin safety
requirements for exporting their products. This collaborative
encourages better planting, harvesting, and drying practices
and has trained more than 800 staffers and farmers to date. In
addition, the International Crop Research Institute for the
Semi-Arid Tropics has set up labs in Malawi and other countries
that offer affordable enzyme-linked immunosorbent assay testing
for rapid sampling of crops.
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Management Key To Asia's Future Water
Supply
One of the main messages of Asian Water Development
Outlook 2007, a report by the Asian Development Bank, is
that proper management, not volume, is the key to maintaining
sufficient water supplies in Asia in the face of increasing
urbanization, industrialization, population growth, and climate
change. The report emphasizes that current trends in wastewater
management make it harder and more expensive to provide clean
water. National policies must also consider the water needs of
the energy sector, an often overlooked draw on resources. The
report states that Asia has the expertise and technology to
ensure an adequate supply of clean water—if that
expertise and technology can be fully implemented.
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A Helping Hand for HCFCs
A September 2007 adjustment to the
Montréal Protocol called for production and consumption
of hydrochlorofluorocarbons (HCFCs) to phase out in developing
countries by 2013, 10 years ahead of the original Protocol
schedule. Now UNEP and the Swedish EPA have announced they will
help developing countries identify commercially available
alternatives to achieve this goal. UNEP has also launched the
HCFC Help Centre at http:
//www.unep.fr/ozonaction/topics/hcfc.asp to educate policy
makers about HCFCs and their alternatives. Sweden has largely
phased out HCFCs, which were used to replace ozone-depleting
chlorofluorocarbons before they too were found to harm the
ozone layer and significantly contribute to climate change.
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Asthma Brochures Fail Test
Governments need to spend health dollars
in ways that can benefit the most people. A study in the Autumn
2007 issue of Ethnicity & Disease looked
at the cultural specificity of asthma education brochures distributed
in
Wisconsin and found that many were ineffective at educating
vulnerable populations about asthma care and prevention. The
authors found several translation errors in Spanish-language
materials and a lack of attention to cultural issues relevant
to American Indian groups (such as the use of smudging and a
tendency to distrust maintenance asthma medication). There also
were no materials aimed specifically at black residents, who
make up a large part of the Wisconsin population and have a
disproportionately high incidence of asthma. The study used a
cultural competency analysis tool developed by the Wisconsin
Asthma Coalition Disparities Workgroup, which the authors say
could serve as a model for other states seeking to assess their
own materials.
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Images (top to bottom): Stuart Freedman/Panos Pictures; J. Tart/EHP
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