Up till 2018, a statement in Ontario’s Hunting Regulations Summary recommended that hunters avoid eating the liver and kidneys of deer, moose, and elk due to concerns about cadmium in these organs. This advice had been in place since the late 1980s.
In 2019, that recommendation was removed from the regulations. Not because the ministry abandoned it. Rather, they moved this info to the Hunting Notices and Updates webpage here.
There, the recommendation reads as it did before: “The ministry recommends that people not eat the liver and kidneys of moose, deer, and elk because of concerns about cadmium levels in these internal organs.”
How does cadmium enter the liver?
“Cadmium can be released by both natural and anthropogenic sources, however the primary source is normally from natural erosion and weathering of the land. Cadmium can be absorbed by plants, and subsequently move through the food chain and can bioaccumulate in some internal organs (e.g. liver and kidneys as filtering organs) of species like deer and moose. Concentrations can vary by species and environmental conditions,” said MNRF Senior Media Relations Officer Jolanta Kowalski. (Anthropogenic refers to environmental change caused or influenced by people, either directly or indirectly. This generally refers to pollution.)
Livers vs. kidneys
Studies have shown that kidneys accumulate higher levels of cadmium than the liver of the same animal.
What are the risks?
According to the US Center for Disease Control, exposure to low levels of cadmium in air, food, water, and particularly in tobacco smoke overtime may build up cadmium in human kidneys and cause kidney disease and fragile bones. Cadmium is also considered a cancer-causing agent. According to the Maine Department of Inland Fisheries and Wildlife, symptoms of acute cadmium poisoning include severe nausea, vomiting, diarrhea, muscle cramps, and salivation.
Worse in older animals?
Research has shown that cadmium levels increase with animal age. Studies have also shown that moose accumulate more cadmium in organs than deer. Therefore, if you choose to eat liver or kidneys, it’s likely safest from a young, healthy deer, though still not recommended by the MNRF.
What was the science behind the recommendation?
The Ontario cadmium recommendation emerged from a 1988 study entitled Cadmium levels in Ontario moose and deer in relation to soil sensitivity to acid precipitation, which was in affiliation with the Wildlife Branch of the then Ministry of Natural Resources. Most jurisdictions acknowledge that cadmium accumulates in deer, elk, and moose livers and kidneys. There is no general agreement on how much, if any, is safe for consumption.
What others are saying
New Hampshire recommends hunters not consume deer liver and kidney. So does Maine, which notes that several US states, Canadian provinces, and Scandinavian countries do the same.
Other jurisdictions, such as Alaska, do not recommend restrictions in consumption of these organs from deer and moose.
Some jurisdictions only recommend moderate consumption of livers and kidneys from young animals and advise smokers and children to avoid these organs altogether.
Originally published in Ontario OUT of DOORS’ 2022-2023 Hunting Annual