|
March 14, 2003
Study tracks effects of
contaminants in Nunavik infants
Omega-3 fatty acids
counteract effects of pollutants
ODILE
NELSON
Despite the high levels
of pollutants in country foods, Nunaviks health board recommended last
month that women continue eating some traditional foods during their childbearing
years because the benefits balance the risks.
Dr. Serge Déry,
public health director for the region, made the recommendation after learning
the results of a multi-year Laval University study conducted in Puvirnituq,
Inukjuak and Kuujjuarapik.
The study, led by Dr.
Gina Muckle and presented at a meeting on Arctic contaminants in Ottawa last
week, confirmed previous research showing Inuit women are exposing their unborn
babies to high levels of mercury, PCBs and lead because the pollutants accumulate
in the fat of marine animals.
But while the study linked
the contaminants to subtle effects on the mental and physical development of
infants, it also suggested country foods rich in omega-3 fatty acids may counteract
these negative effects.
For this reason, as well
as the social benefits of community feasts and the physical health benefits
of hunting and fishing, Déry said country food remains a healthy choice
for most Nunavimmiut.
"Basically what we
told them was that country food is still the best for the general population
of Nunavik," Déry said in an interview last week.
"Having said that,
for women of childbearing age and who are pregnant we said it is first important
to have access to a good quantity and variety of food. When this is achieved,
if it is possible, they should select country foods rich in omega-3 fatty acids
and lower in pollutants."
For women between the ages
of 13 and 45, he said, this means choosing Arctic char and caribou over muktuk
because marine mammal fat has a higher concentration of pollutants. It also
means selecting younger animals over older animals since the younger animals
are less contaminated.
The health board suggests
women begin this dietary change when they are in their early teens because some
contaminants can stay in the body for more than 20 years.
In an interview this week
from her office in Montreal, Muckle said she presented the results of her study
to Nunaviks Nutrition and Health Committee in December 2002.
Researchers and health
officials exchanged information for several months to come up with the public
health recommendations. They then released the information to Nunavimmiut in
mid-February a month before it was released internationally.
Muckle said the committee
and health boards approach to her study was innovative.
"They take into account
the whole picture of country food in Nunavik knowing that country food
is very important for many aspects of the general health of the population and
that there is not much alternative," she said.
"Store-bought foods
mean omega-3 fatty acids would be decreased in a significant amount and a switch
to a more southern diet would increase certain illnesses like diabetes and obesity."
Muckles study examined
mercury, lead and PCB levels in umbilical cord blood samples from 110 babies
between 1996 and 2001. She also took blood, hair and breast milk samples from
the babies mothers.
When the babies were born,
she measured their weight, height and head circumference and then tracked their
physical growth over the next year. She used simple recognition tests to measure
the infants memory and problem-solving ability at six and a half months
and 11 months. She also tested the infants vision and such motor skills
as walking and standing.
Her study made several
important findings, she said. The first was that unborn babies in Nunavik are
exposed to two to three times the level of PCBs, two times the rate of lead
and a significantly higher level of mercury than general populations in southern
Quebec.
Secondly, the study showed
for the first time (after accounting for such factors as a mothers social
background or drug use and the level of mental stimulation showered on the infant)
that each of these pollutants has a specific but subtle negative effect on infant
development.
PCB contamination was shown
to decrease a newborns weight and affect its ability to recognize and
remember objects. Exposure to lead made it subtly more difficult for infants
to process new information. High mercury levels affected a babys ability
to remember while distracted.
But Muckle said the studys
third discovery, and the one that clearly influenced the public health boards
recommendations, was the most significant: infants who had been exposed to a
high level of omega-3 fatty acids while in the womb are partially protected
against the effects of PCBs.
"For example, a woman
working in a plant may be exposed to a similar level of PCB but the source of
exposure is not fish or consumption of country foods," she said. "So
the baby will not get as much omega-3 fatty acids. Those results are showing
the PCB effects may be stronger in those populations [that do not get fatty
acids]."
Muckle said she hopes to
examine the children at seven years of age to see if any long-term effects on
memory, attention span or activity level.
According to Déry,
if future studies show a more substantial link between child development and
the pollutants in country food, the health board would reassess its recommendations.
But Muckle said any future
study would depend on the federal governments renewal of the Northern
Contaminants Program. The program provided most of the funding for Muckles
study and the government has made no promises to renew it.
|