Hakai Magazine

Coastal science and societies

illustration of neolithic hunters
The seafood eaten by Neolithic Norwegians was stuffed full of heavy metals. Illustration by De Agostini Picture Library/Getty Images

Stone Age Diets Were Far From Healthy

Even in the Neolithic, Norwegians were overloaded with heavy metals.

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by David Adam

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Want to serve up an authentic Stone Age meal for your paleo-dieting friends? First, take your fish or seal meat and marinate it for thousands of years in a briny mixture of cadmium and lead (available in all good stores and car batteries). Sprinkle on mercury to taste, and serve with nuts and berries. Any leftovers? Store them at the back of your shelter for the winter, or until the severe and perhaps lethal heavy metal poisoning takes hold.

As much as we might like to believe that ancient foods were pure and free of the taint of industrialization, a new study paints a very different picture of the way many of our early ancestors ate. Remains of meals eaten by people living in northern Norway about 8,000 years ago show they were tainted by massive amounts of toxic heavy metals—with concentrations up to 22 times higher than the levels allowed by modern food safety standards.

“We were greatly surprised by the levels of contamination,” says Hans Peter Blankholm, an archaeologist at the Arctic University of Norway, who led the new study. The findings indicate the Stone Age ocean was awash with huge quantities of toxins, and that food taken from it was unhealthy, and perhaps unsafe, to eat.

Blankholm’s team looked at fragments of bones from Atlantic cod and harp seals in food refuse collected from well-studied Stone Age settlements in the Varanger Peninsula, above the Arctic Circle. Using a dentist’s drill, they extracted samples and checked them for contaminants.

In the cod bones, they found levels of cadmium up to 22 times higher than today’s recommended limits, while lead was three to four times higher. The lead levels in seal bones were similarly high, while cadmium levels were 15 times higher than today’s guidelines. Mercury levels in both were below the recommended limit, but were still high—almost as high as the elevated levels found in Arctic fish today.

The scientists say the heavy metal levels in the marine foods are an example of how pollutants steadily build up in the tissues of sea creatures through the food chain: a process called bioaccumulation. In humans, significant exposure to cadmium is known to cause cancer and kidney, liver, and lung diseases, with children and pregnant women most at risk.

Where did the heavy metal pollution come from? The scientists suggest it was down to climate change. Rapid warming and sea level rise about 10,000 years ago may have eroded the land and washed stocks of minerals from the soil into the sea.