Ötzi the Iceman enjoyed a very high-fat diet

Imagine you’re out for an evening of pizza and beer and on the way home you’re flash-frozen into a block of ice, only to have hordes of scientists thaw you out a few thousand years later and systematically delve into every conceivable aspect of your long-lost life.

Such has been the fate Ötzi, also known as the Iceman, whose frozen body was discovered in 1991 by a pair of German tourists hiking in the southern Tyrol on the border between Austria and Italy. Ötzi’s corpse was found at an elevation of 3210 metres above sea level, where it had rested undisturbed for more than 5300 years. 

In the latest examination, researchers reporting in the journal Current Biology say their in-depth analysis of his stomach contents reveals much about his dietary habits. Among other things, they say, his last meal was heavy on fat.

When Ötzi was discovered, what was at first thought to be the corpse of some unfortunate modern-day climber was eventually revealed to be that of oldest naturally preserved ice mummy.

Since then, study of Ötzi, his clothing and the tools and weapons he carried have revealed much about life in the Copper Age, or Eneolithic Period.

Much has been written, for example, about his more than 50 tattoos.

Researchers led by Frank Maixner, of the Eurac Research Institute for Mummy Studies, in Bolzano, Italy, used highly detailed biological analysis to reconstruct the Iceman’s last meal. They found that he had a “remarkably high proportion of fat in his diet”.

The fat would have come from eating wild game such as red deer and ibex, a type of goat found in the mountainous regions of Europe, north central Asia and northern Africa.

The Iceman’s diet also included einkorn, one of the earliest known forms of cultivated wheat, and Maixner says they also found traces of a type of toxic bracken, or fern, in his stomach.

Despite previous in-depth studies into the Iceman’s physiology, Maixner says his team’s analysis hadn’t been done previously because scientists had been unable to find the corpse’s stomach, which had moved up into the body cavity during the mummification process.

It was finally spotted in 2009, during a re-investigation of CT scans, and an effort to analyse its contents was launched.

“The stomach material was, compared to previously analysed 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 Ötzi’s diet,” Maixner says.

The researchers combined standard microscopic and advanced molecular approaches to determine the exact composition of the Iceman’s diet. This allowed them to make inferences based on ancient DNA, proteins, metabolites, and lipids.

The analysis identified ibex tissue as the most likely fat source. In fact, about half of the stomach contents comprised animal fat.

The researchers say the high-fat diet “totally makes sense”, given the extreme alpine environment in which Ötzi lived and where he 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,” says Albert Zink, also from the Eurac Research Institute.

“The Iceman seemed to have been fully aware that fat represents an excellent energy source.”

Although the presence of toxic bracken particles is more difficult to explain, the researchers say it’s possible the Iceman suffered from intestinal problems related to parasites and ate the bracken as a medicine. Another possibility is that he may have used the fern leaves to wrap food and ingested toxic spores unintentionally.

The researchers say they plan to conduct further studies aimed to reconstruct the ancient gut microbiomes of the Iceman and other mummified human remains.