A new study from the University of Ottawa has found a link between persistent organic pollutants (POPs) and high cholesterol levels among Inuit. The study follows earlier work that found a similar link between the group of chemicals and some kinds of diabetes.
That group of pollutants includes well-known chemicals like polychlorinated biphenyls (PCBs) and the pesticide DDT.
Many have been restricted under the international Stockholm Convention, but, true to the "persistent" part of their name, remain in the environment.
"As researchers we're concerned with what types of levels are found, and what are the health implications of those exposures," says Kavita Singh, a PhD student who published the recent paper, drawing on data from the 2007-2008 Inuit Health Survey.
In Singh's study, PCBs were associated with high levels of total cholesterol and low-density lipoproteins, the so-called "bad" cholesterol. It adds to the weight of evidence that the chemicals are connected to poor health outcomes.
"Especially with PCBs, there's a lot of evidence collecting from several different populations that they may be linked with chronic diseases, especially diabetes."
The chemicals, though mostly originating in the south, accumulate in the Arctic. They're also known to be magnified through the food web, concentrating in predators like whales, seals, polar bears and, eventually, humans.
"A lot of people actually find it surprising that Inuit are exposed to such high levels of contaminants," says Singh, noting that the pollutants travel to the north through the atmosphere and water. "The Arctic ends up acting as a sink."
'Do we become farmers?'
Despite the higher levels of pollution in country foods like seal and whale, Inuvialuit elder Roy Goose says he has no plans to change his diet.
"Our bodies are probably riddled with POPs and all kinds of other pollutants in the water column," he says. But, "we were meant to eat seal meat and Arctic char and whales from the ocean and waterfowl from the air. That's who we are."
Goose says he doesn't know how he can limit his exposure to pollutants found in most of the foods native to his culture.
"Do we become farmers?" he asks. "I think not."
Singh says she is not encouraging Inuit to give up their traditional diets; in fact, she hopes her research will not change what Inuit eat.
"It's still important that the Inuit continue their traditional diets, because we know that they have a lot of benefits," she says.
Singh's study and those that have come before it have not yet proven that the chemicals are causing the conditions they have been linked to; that would require a different kind of long-term study of a group of individuals living different lifestyles. But studies of animals in laboratory conditions have shown there are ways POPs can cause similar issues.
The University of Ottawa researchers are also looking at heavy metals like arsenic and methyl mercury, and how they may affect cardiovascular disease.