5,300-year-old iceman's last meal was remarkably high in fat

The oldest naturally preserved ice mummy ate a last meal extremely high in fat content, scientists have discovered. Photo courtesy of the South Tyrol Museum of Archaeology
 
The oldest naturally preserved ice mummy ate a last meal extremely high in fat content, scientists have discovered.

Researchers published a new study in Current Biology on Thursday, reporting insights into the nutritional habits of European individuals in the Copper Age, more than 5,000 years ago. The study is the first in-depth analysis of the stomach contents of the mummy known as Otzi, or the Iceman, providing a glimpse into our ancestor's ancient dietary habits.

The Iceman was discovered in 1991 by German tourists in the Eastern Italian Alps. Scientists were initially unable to identify the Iceman's stomach because it had moved up during the mummification process. But in 2009, during re-investigation of CT scans, scientists spotted it and launched an effort to analyze its contents.

Researchers used a complementary mutli-omics approach combined with microscopy to reconstruct the Iceman's last meal. The high proportion of fat came from wild meat from ibex and red deer, cereals from einkorn and traces of toxic bracken, according to Frank Maixner of the Eurac Research Institute for Mummy Studies in Bolzano, Italty. Bracken is a genus of large ferns.

Maixner and his colleagues suspect he took the bracken as medicine to treat intestinal problems related to parasites found earlier in his gut. Or perhaps he used the fern's leaves to wrap food and ingested the toxic spores unintentionally. The analysis indicated that the wild meat was eaten fresh or dried.

"The stomach material was, compared to previously analyzed lower intestine samples, extraordinarily well preserved, and it also contained large amounts of unique biomolecules such as lipids, which opened new methodological opportunities to address our questions about Otzi's diet," Maixner said.

The researchers combined classical microscopic and modern molecular approaches to determine the exact composition of the Iceman's diet prior to his death. It's a broad-spectrum approach which allows them to make their inferences based on the ancient DNA, proteins, metabolites and lipids.

They found ibex adipose tissue as the most likely fat source. Half the stomach contents were composed of adipose fat. They expected the high-fat diet because of the extreme alpine environment where the Iceman lived and was found.

"The high and cold environment is particularly challenging for the human physiology and requires optimal nutrient supply to avoid rapid starvation and energy loss," said Albert Zink, who also participated in the study. "The Iceman seemed to have been fully aware that fat represents an excellent energy source."

The analysis also identified traces of the original gut bacterial community in the Iceman's intestinal contents. The researchers plan to conduct further studies to reconstruct the ancient gut microbiomes of the Iceman and other mummified human remains.

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