On a foggy day in August 1936, an anthropologist and his crew set sail for Kagamil Island, a small volcanic speck of hot springs and cliffs in the Bering Sea. A person identified as “Brown Bear” had told them of a cave full of mummies and other human remains. Shortly after landing, they found an opening in some rocks near a steam jet.
According to the notes of the anthropologist, Ales Hrdlicka, the cave contained “wonderful riches”:
“Space within cave is limited, in most of it one can not stand up, in none of it can use shovels; must work with hands like badgers. ... As the salt deposit is penetrated into, there appears mummy after mummy, in different states of preservation — male, female and especially children ... a huge whale shoulder blade ... two entire kayaks.”
Nearly 80 years later, the mummies from Kagamil and elsewhere have excited the interest of scientists who say what they have learned from the remains challenges a central tenet of conventional thinking about what we ought to eat.
Heart disease, the leading cause of death in the U.S., is often blamed on modern diets and a sedentary lifestyle. According to this thinking, if only people ate the “right” foods and exercised more, they could live longer. This view is encapsulated in the current version of the government's Dietary Guidelines for Americans, which are under review and being reissued soon. They have long recommended dietary habits deemed good for your heart — lower intakes of saturated fat and salt, more emphasis on lean meat and seafood.
“Poor diet and physical inactivity are associated with major causes of morbidity and mortality in the United States,” according to those guidelines.
But examinations of the bodies of the Unangans from Kagamil Island and other pre-modern people indicate that, in fact, the modern scourge of heart disease is not at all new, and that people who exercised more than we do as a matter of necessity, and whose diet was free from modern temptations, also suffered striking levels of heart disease, according to the researchers.
In recent years, X-ray based scans of mummies from around the world - including the hunter gatherers of Kagamil as well as those from ancient Egypt, Peru and the American Southwest — found signs of heart disease or atherosclerosis, the plaque lining the arteries near the heart.
Even the reconstructed man shown above, who lived 5,000 years ago, showed signs of atherosclerosis. His mummified remains were discovered in the Italian Alps in September 1991.
For years, scientists have argued over the extent to which modern diets ought to be blamed for the high rates of heart disease. As an American Heart Association publication summarizes: "There can be little doubt that the Western diet is closely tied to the development of atherosclerosis."
This belief is widely shared, but it has led to a fierce debate over how exactly people ought to reform their diet. Many leading health groups, including the American Heart Association, have concluded that a person's heart disease risk depends on "both the quantity and quality of fat in an individual's diet," and they urge people to reduce the amount of animal products — especially beef, pork and lamb — that they consume.
That approach has met strong criticism in recent years by critics who argue instead that a diet rich in proteins and lower in carbohydrates — the so-called "cave man" approach — makes it easier to maintain a stable weight and metabolism.
The new research may undercut both positions. By turning up evidence of heart disease in populations with widely varying diets, the mummy research suggests that maybe some other unrecognized cause is at work besides what we choose to eat.
“Although commonly assumed to be a modern disease, the presence of atherosclerosis in pre-modern human beings raises the possibility of a more basic predisposition to the disease,” according to the researchers, who include specialists in cardiology, X-rays, anthropology and other fields.
As the research has found its way over the years into some of the world’s most esteemed medical journals, including the Lancet, which in 2013 published an article about four groups of mummies, critics of the work have charged that the number of mummies that have been examined is relatively small — only a couple hundred or so — and insufficient to support broad conclusions. Moreover, the bodies have been dead a long time, and maybe some other chemical changes create the appearance of arterial plaque.
But the very basic reaction to the mummy research has been this: Given all the research linking heart disease and diet, the results seem too unlikely to believe.
“In my opinion the ancient populations did intense physical activity and followed a diet rich in vegetable, free from saturated fats, and therefore [had a] low risk of developing atherosclerosis,” Gino Fornaciari a paleopathologist at the University of Pisa, wrote in an email.
In the past, he said, only “elite individuals” such as kings would have suffered from atherosclerosis because they could have afforded foods that match those of the modern diet.
He said inaccuracies in reading the scans of tissues that were long dead, and dessicated, might have led to inaccuracies in conclusions. The scans, known as CT scans for computerized tomography, are based on computerized analysis of multiple X-ray images. The plaque that causes heart disease consists in part of calcium; those calcified remnants remain in the mummies and show up in the scans.
“On the basis of my long experience,” Fornaciari said, many false findings are possible.
But the mummy researchers, including cardiologists who look at such scans in living humans, note that the appearance of the atherosclerosis in the CT scans in the mummies is “virtually identical” to the appearance of atherosclerosis in their patients. This similarity, they said, makes it unlikely that some change in the ancient bodies has created an illusion of atherosclerosis.
Moreover, the mummy researchers said, while the Egyptian mummies may have been elite individuals that don't represent the general population, the mummies from other cultures likely are more representative of the populations they came from. And the fact that mummies from around the world show signs of heart disease makes their case that much more compelling, other researchers said.
“These results confirm that atherosclerosis was present in ancient civilisations with wide cultural differences,” Anthony M. Heagerty, a cardiologist at the University of Manchester, wrote in response to the Lancet article, citing other research along similar lines.
Moreover, the researchers can point to other evidence indicating that heart disease is an ancient affliction.
One text from Egypt dating as far back as 1550 BCE said: “If thou examinst a man for illness in his cardia, and he has pains in his arms, in his breast and on one side of his cardia … it is death threatening him.”
What is more difficult to know from the mummies is how far advanced the heart disease might have been in the individuals, or how much they may have felt the symptoms.
But the scientists said that some of the signs of heart disease appear to have been severe enough that they very likely caused people to suffer. For example, scientists point specifically to one of the mummies from Kagamil Island, a 40-ish woman who lived about 1900.
“What’s remarkable about her is that she would have had a marine diet, and consumed a lot of fish oil,” said one of the researchers, Gregory Thomas, medical director of the Heart Institute at Long Beach Memorial Hospital in Long Beach, Calif. “She ate plenty of sea lions and whale and fish. Inland there would have been berries and leaves."
Yet the scientists found evidence of severe atherosclerosis in two of the three arteries that supply blood to the heart.
For the cardiologists among the researchers, the ramifications of the work are not merely academic. They have changed the way they think about the conventional diet advice typically dispensed to heart patients.
Randall Thompson, a cardiologist at St. Luke’s Mid America Heart Institute in Kansas City and a professor at the University of Missouri-Kansas City School of Medicine, said the research has changed the way he views what we can do to prevent heart disease.
”I’m a clinical cardiologist and I want people to eat a healthy diet, but this puts all that in perspective. ... At least part of this disease is not explained by traditional risk factors. These ancient people didn’t have preservatives, everything was organic, they didn’t smoke and they got plenty of exercise. But ... the amount of atherosclerosis in ancient times isn’t much different from what you see in modern times. If you account for age, it looks like we’re in the same ballpark.”
Thomas said something similar.
“When I became a cardiologist 30 years ago, I was pretty dogmatic about the low-fat, low-cholesterol diet to prevent heart disease. [But] we’ve been unable to find a culture without atherosclerosis and I’m not really sure what to eat, personally, to delay atherosclerosis, or what to recommend to patients. Of late, I tell people to stay lean.”
Staying lean, he says, keeps cholesterol levels in the bloodstream lower, and helps stave off heart disease.
“We have this wistful hope that if we go back to nature that we would markedly delay atherosclerosis," Thomas said. "But these people ate a natural diet, and they still had heart disease. I no longer think that way.”