Survival in the Arctic has always been about finding food in a harsh land, as many European­ explorers learned the hard way. Some, such as Roald Amundsen of Norway, made good use of the nutritional wisdom of the Arctic Inuit, whom he met during his exploration of the Northwest Passage from 1903 to 1906. This traditional knowledge would later prove instrumental to the success of his 1911 discovery of the South Pole.

Today, the tables are turned. As aboriginal northerners have welcomed economic development­, it has led to profound changes in how they eat. Many more meals are made up of store-bought, processed foods that have introduced unprecedented amounts of salt, sugar­ and carbohydrates into their diet, creating such health problems as diabetes. The preferred ‘country’ diet —— marine and land animals that have nourished northern aboriginals for millennia­ —— are proving to be just as worrisome. Coming from the top of the food pyramid, these animals are increasingly being compromised by various contaminants. 

Laurie Chan, who holds the Canada Research Chair in Toxicology and Environmental Health at the University of Ottawa, has spent much of his career studying these persistent organic pollutants (POPs) that travel so readily in the atmosphere from current and past industrial activities, including the production of PCBs or the spraying of chlorinated pesticides. Most of us will wind up consuming these agents in amounts so small that any potential health effects will be limited. In the Arctic, however, the fatty tissues of country food concentrate POPs in much higher amounts. The health problems these pose have occupied Chan’s attention for more than two decades. Now, as director of the University of Ottawa Center for Advanced Research in Environmental Genomics (CAREG), Chan is bringing the latest techniques of molecular biology to bear on the environmental stressors of genome function and expression. More specifically, he is looking at how genes affect our individual response to contaminants in food, making it possible to strike a crucial balance between minimizing the intake of such contaminants without compromising an otherwise healthy diet.

An Inuit hangs Arctic char to dry in the sun. This fishy delicacy is called pipsi in Inuktitut. Photo credit: Lee Narraway/NMC 

How did you become interested in environmental toxicology?

I grew up in Hong Kong, where I witnessed the deterioration of habitats and a loss of diversity at a rate that you wouldn’t believe. I was also a scuba diver, so I could even see this effect under water. After studying marine environmental toxicology, I came to Canada for post-doctoral work in pathology at the University of Western Ontario. With my marine environmental ecology background, that subsequently built upon my interest in ecosystem health and how changes in the environment affect human health.

So how did this interest take you to Canada’s north?

It was the 1980s and the federal government had introduced the Green Plan, which had a significant Arctic environment component. This is when we began to pay attention to the presence of contaminants in the North, including the contaminants polychlorinated biphenyls (PCBs). Initially everyone was eager to blame the Cold War Distant Early Warning radar stations. There certainly was a lot of this contamination at these sites, but that was just local pollution. We were finding PCBs everywhere, which meant that it was travelling from other places. Then we started looking at contamination in the animals that the local populations were consuming. Because my training was in environmental science and human health, it came in handy. Together with Harriet Kuhnlein, Tim Johns and Olivier Receveur, we founded the Centre for Indigenous Peoples’ Nutrition and Environment at McGill University in the 1990s and worked as a team to try to understand the risks and benefits of eating country food in the north. 

How are pollutants making their way into that food?

Chemical pollutants are persistent in the environment —— that is, they don’t break down —— and are carried to the North by atmospheric and oceanic currents. Many of them are lipophilic and can be bioaccumulated and biomagnified along the food chain, reaching higher levels in top predators like ringed seals and beluga whales.

How did you study this problem?

I’ve been to the North too many times to count, about two or three times every year, although I do not do field work these days. As part of the Centre for Indigenous Peoples’ Nutrition and Environment, for instance, we spent 10 years on three comprehensive dietary surveys in 44 Canadian Arctic and sub-Arctic communities. This involved randomly selecting people for interviews and more than 3,600 interviews were conducted. There was also direct sampling of hundreds of different food items, so that their nutritional content could be measured along with the presence of contaminants. People in some places may be getting more than a third of all their calories from dozens of different plants and animals in these regions, which means they are also taking in those contaminants.

Should they just stop eating these plants and animals?

The problem is that these same foods are excellent sources of essential nutrients, and there is really no better way for them to get some of those nutrients. I was part of a group that examined this problem recently with respect to the levels of mercury found in fish and marine mammals, and what that does to the levels of mercury in the blood of people who eat those animals. Our results were published in 2013 in the Journal of Nutrition. When we surveyed groups in Nunavut, Nunatsiavut, and Inuvialuit, we did find higher levels of mercury in their blood, but we suggested that this increase might be balanced against the very healthy nature of these foods. To a lesser extent, the same idea applies to many of us even outside the North. Here in North America, we don’t eat too much fish, so the mercury concentration found in your hair is on average less than one part per million. I have two, three or four times that amount in my hair, because I eat a lot of sushi. Health Canada advises women of childbearing age not to have mercury levels in their hair higher than two parts per million. If you eat tuna sushi once a week, you’ll have that high a level. In a lot of First Nations communities I’ve visited, they eat that much fish. People like fish and it’s a good source of nutrients.

So how do you strike this balance between maintaining a healthy diet and taking in known contaminants?

In the past 20 years, my research team has done a whole lot of chemical analyses, looking for biomarkers for toxicity in human population studies and laboratory studies using animal models. If you want to know about heart function, for example, we test for cholesterol. If you want to know about kidney function, we can test urea in urine samples. But when we wanted to know, for example, whether high levels of mercury in fish were causing brain damage in people who eat a lot of seafood, it turned out we didn’t have a chemical test for neural performance. Then, about 10 years ago, a series of animal experiments revealed an enzyme, monoamine oxidase (MAO). High levels of mercury in the blood lowered the activity of MAO in the brain.

The diet of Arctic aboriginals consists largely of protein in the form of caribou, Arctic char, salmon, walrus, musk ox, seal and whale meat. Laurie Chan of the University of Ottawa has discovered high levels of mercury in the blood of First Nations due to persistent organic pollutants in the atmosphere. Photo credit: Tessa Macintosh/NMC 

That sounds promising.

We started looking at MAO in the blood of people who have different levels of mercury exposure. In some studies we found effects, but in others we didn’t. It turned out to be affected by a number of things, not just mercury. You needed to do multiple regressions to pick out some of the confounding factors. One of those factors is smoking, another is age. MAO is not much of a good indicator for mercury as it is not specific enough.

That’s a frustrating discovery; how did you deal with it?

We turned to environmental genomics, which came with some new tools. The ‘omics’ approach includes the transcriptome, proteome and metabolome, so you can look at the changes in many proteins and many genes at the same time. Instead of one biomarker, you’re looking at hundreds and even thousands of biomarkers, and how they change in relationship to each other. You’re looking at patterns. These patterns serve as a kind of fingerprint. With powerful bioinformatic software, you can look at how the profile of the gene/protein/metabolite changes in response to an agent. The software can even tell you which bodily system might be affected. So when one biomarker is not specific enough, if 10 or 100 biomarkers change in a certain direction, the chances of being specific are better.

In addition to progress in molecular biology, you have also taken advantage of the traditional knowledge found in aboriginal cultures.

Traditional knowledge can broadly be divided into areas. One is ecological knowledge that no one can dispute. Who can argue with somebody who looks at the sky every day from the same angle for his or her whole life? The other aspect is related to culture and values. You need to respect that, or you don’t deserve to work with these people. My way of working is to totally respect ecological knowledge, along with cultural and spiritual values. How do I integrate it into my findings? Researchers always need to interpret their scientific findings in the context of the traditional knowledge of these peoples.

What has this kind of traditional­ knowledge contributed­ to your work?

People don’t realize that living in the North is not easy. Everything, including humans, is in survival mode. Tiny things that you do — travelling one hour — are a big job. You need skill sets; you need to prepare yourself. And if you go there as a tourist, living there for a short period of time, you need to rely on other people for survival. The local people, the community, they support us. They share with us their back yard. Once you realize this, you see a beautiful system; simple and fragile. It can be disturbed very easily and it’s changing very fast. 

Are there lessons here for the rest of us?

I work with a lot of aboriginal communities, and one thing that they have in common is their worldview of the importance of living in harmony with the environment. People like us, who live in cities, often forget about how our livelihood is dependent upon the environment. They live on the land and know that a healthy environment is critical to everything that they do. Sometimes, we think that in cities we’re very food secure but that is not true. If transport was suddenly cut off, most of us would have no capacity to do anything and food would run out very quickly. Those are things that people forget, that you can’t cut yourself off from the environment. Somewhere there’s a link, and the more we remove it from us, the more fragile our circumstances become.

How do you apply this kind of powerful insight?

In the next few years we hope to focus our work at CAREG in environmental health that includes cross-disciplinary research in ecology, microbiology and toxicology. We will deal with pressing issues, such as the mining and in-situ extraction of oil sands in Alberta. For example, we have very little knowledge about the composition and toxicity of the solvents that are used in the extraction and the residual chemicals that are found in the wastewater. There is active mining exploration in northwestern Ontario. We need to get baseline information in order to develop a sound management plan. We just finished doing baseline studies of nutrition and environmental health at six First Nations communities in that area, and next year we’ll be doing a lot of communications about what we found. Major changes are expected in the physical and socioeconomic environment in these communities. We need to work with the people to develop long-term strategic plans to develop the resources in an appropriate way so that everybody gets long-term benefits, while minimizing the risk of adverse effects to health or the environment.