A new study suggests that hardening of the arteries is an old problem.
Really, really old.
Researchers have found clogged arteries, or what's left of the arteries, in mummies from nearly 4,000 years ago.
The findings - from humans who lived thousands of years before the invention of Twinkies and curly fries - are leading some doctors to reconsider their notions about the causes of heart disease.
Doctors have long assumed that hardening of the arteries - officially known as atherosclerosis, which can lead to heart attacks and strokes - was a disease of modern life, caused by smoking, fatty foods and lack of exercise.
Authors of the new paper, published Sunday in The Lancet and presented at a meeting of the American College of Cardiology in San Francisco, say they were shocked by their discovery.
Finding plaques in the arteries of ancient peoples suggests that it is "either a basic component of aging, or that we are missing something very important that is a cause of atherosclerosis," says co-author Gregory Thomas, medical director of MemorialCare Heart and Vascular Institute in Long Beach, Calif.
More than one-third of 137 mummies sent through a CT scanner had calcification in their arteries, suggesting hardening of the arteries.
Mummies came from around the world: ancient Egypt, where people deliberately preserved the bodies of kings; as well as Peru, the southwestern United States and the Aleutian Islands, near Alaska, where the corpses were naturally mummified by dry air and other conditions. In earlier studies, researchers also have found hardened arteries and arthritis in the famous "Ice Man," a 5,300-year-old mummy found in the Alps in 1991.
In some cases, the mummies' calcified plaques outlasted their arteries, the study says.
Atherosclerotic plaques "are basically a kind of inflamed rock," made of calcium, inflammatory cells and cholesterol, embedded in the wall of an artery, says Cam Patterson, chief of cardiology at the University of North Carolina-Chapel Hill, who wasn't involved in the new study. When these plaques rupture, they cause inflammation and block blood vessels, leading to heart attacks and strokes.
Nearly 4.6 million Americans suffer from atherosclerosis, the leading cause of death in the developed world, the study says.
Researchers expected "that ancient cultures' diets were too good to develop atherosclerosis," Thomas says.
Researchers say they don't know why atherosclerosis was so common in the pre-industrial age.
It's possible that atherosclerosis is part of the natural aging process. It's also possible that humans who lived in the days before antibiotics and an understanding of germ theory dealt with chronic inflammation caused by frequent infections, Thompson says. Inflammation is known to contribute to atherosclerosis. For example, people with inflammatory diseases, such as rheumatoid arthritis and lupus, tend to develop atherosclerosis 10 to 15 years earlier than normal, the study says.
Researchers note that ancient life could have been hard on the arteries in other ways. While these humans lived in a time before tobacco and industrial smokestacks, they typically cooked over open fires, the paper notes. In the Aleutian Islands, people lit and heated their underground homes with lamps made from seal and whale oil, which create high amounts of soot.
Male and female mummies had the same amount of plaque. The mummies' estimated ages range from 2½ years oldto more than 60 years old, with an average age of 36. Mummies of older people had more atherosclerosis.
On one hand, the findings suggest it's possible that older mummies simply had more time to accumulate arterial plaques.
But it's also possible that atherosclerosis serves as a marker for a better diet, says co-author Jagat Narula, a "paleocardiologist" and professor at the Icahn School of Medicine at Mount Sinai Medical Center. So, people who were better nourished were more likely to live into old age, but also more likely to develop arterial plaques.
These ancient peoples have passed their genes on to us.
"Remember that 6,000 years is only a blink of the eye in terms of evolution," says William A. Murphy, a professor of radiology at Houston's University of Texas MD Anderson Cancer Center, who was involved in imaging the Ice Man. "Contemporary humans are essentially identical to our 6,000-year-old ancestors."
The mummies' diets may not have been as healthy as most assume, Narula says. People in the Aleutian Islands were hunter-gatherers who ate a lot of fatty meat and blubber from seals and whales, along with berries, eggs and seafood, the study says.
But Egypt, Peru and the American Southwest were agricultural societies, the study says. Egyptians and Peruvians also domesticated animals, giving people a more steady supply of food, including eggs, Narula says.
Many modern Americans have embraced variations of the "paleolithic diet," assuming that ancient hunter-gatherers had a healthier, more balanced diet, says Marlene Zuk, a biologist at the University of Minnesota and author of "Paleofantasy: What Evolution Really Tells Us About Sex, Diet and How We Live." These diets tend to exclude processed foods, as well as dairy and grains, which came into existence after people transitioned to agriculture.
Zuk says the new study suggests that embracing this kind of diet isn't enough to stave off heart disease. It's likely that our risk of disease is related to a combination of environment, lifestyle and genes, she says.
"Does that suggest we should just give up and gorge ourselves on steak?" Zuk asks. "No. But we often idealize some past where we all ate a certain thing, and assume that if we could just eat that way, then we'd all be healthier."
And while heart disease may be in our genes, it doesn't have to be in our future, Narula says. Plenty of studies still show that avoiding tobacco, eating healthy and exercising reduce the risk of heart attacks, strokes, diabetes and cancer. Murphy notes that most of the decline in heart disease in recent decades is the result of ower smoking rates.
Narula says, "We should not promote the sentiment that this is an inevitable disease."