Scandinavian scientists studied the bones of fish and animals that the inhabitants of modern Norway ate in the Stone Age. It turned out that the remnants of food of ancient people contain high concentrations of heavy metals hazardous to health. The research results are published in the journal Quaternary International.
The "simple" diet of primitive people, consisting of "environmentally friendly" natural products, or rather the way the followers of the newfangled and very popular paleo diet, consisting of unprocessed or poorly processed foods with an emphasis on seeds and nuts, fish and meat, could be very harmful. This is evidenced by the results of a study conducted by scientists from Norway and Sweden.
The authors examined the so-called "kitchen pits" - which archaeologists call "middens" or "kjokkenmedings" - filled with the bones of marine life found at the Neolithic sites on Varanger Island in polar Norway. The diet of the people who lived here from 6300 to 3800 years ago was dominated by marine animal food.
Scientists have performed chemical elemental and isotopic analyzes of collagen extracted from the bones of Atlantic cod (Gadus morhua) and harp seal (Phoca groenlandica) collected at the site, which fed on the ancient inhabitants of the Scandinavian Peninsula, and found they had extremely high levels of cadmium and lead. The contents of mercury were also high, although the latter were within the limits of concentrations safe for humans.
"On average, the level of cadmium in the bones of Atlantic cod was 22 times higher than the currently recommended maximum permissible concentrations, and the level of lead was 3-4 times higher. In the bones of seals there was 15 cadmium, and lead 3-4 times higher than the MPC," - says the study.
According to the European Food Safety Authority (EFSA), the recommended safe limits for cadmium and lead are 50 and 300 nanograms per gram, respectively.
Cadmium is found in the soil and accumulates in the body, especially in the liver and kidneys, causing cancer, internal diseases and osteoporosis. Lead is also found in soil and accumulates in the bones of the skeleton, damaging the brain and nervous system. Mercury, when ingested, can cause serious neurological disorders and immune diseases.
The authors believe that high concentrations of heavy metals in the bones of marine life at that time were associated with climatic changes that occurred after the end of the last ice age about 11,700 years ago - a rise in sea level and an increase in temperature in its surface layer.
The researchers do not elaborate on how climate change led to the accumulation of toxic heavy metals in organisms, but they warn that similar climate changes on the planet, taking place today, could be just as dangerous.
It should be noted that the bones of land animals - deer, hares and waterfowl, which were also found at the sites of ancient people, did not contain dangerous concentrations of harmful metals.
In any case, "it hardly sounds like a healthy diet," the study noted. The foods that modern man eats, according to the authors, are much safer.