Study tracks effects of contaminants in Nunavik infants

ODILE NELSON

Despite the high levels of pollutants in country foods, Nunavik’s 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 Nunavik’s 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 board’s 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.”

Muckle’s 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 mother’s 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 newborn’s 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 baby’s ability to remember while distracted.

But Muckle said the study’s third discovery, and the one that clearly influenced the public health board’s 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 government’s renewal of the Northern Contaminants Program. The program provided most of the funding for Muckle’s study and the government has made no promises to renew it.