Clogged arteries are seen as the quintessential symptom of an unhealthy modern lifestyle. But the condition was common across the ancient world, even among active hunter–gatherers with no access to junk food, a study of mummies has found.
“There’s a belief that if we go back in time, everything’s going to be OK,” says cardiologist Greg Thomas of the University of California, Irvine, a senior member of the study team. “But these mummies still have coronary artery disease.” The paper is published in the current issue of The Lancet1.
Blocked arteries
In atherosclerosis, arteries become narrowed and hardened by plaques — made up of cholesterol and immune cells called macrophages — that build up in their walls. The condition can lead to heart attacks, stroke and other cardiovascular diseases and is the leading cause of death in the developed world.
A lack of exercise and a diet high in saturated fat — both of which increase levels of 'bad' cholesterol in the blood — are thought to increase the risk of plaques building up. This has led to the suggestion that to avoid heart disease we should try to live more like our hunter–gatherer ancestors, on a diet of unprocessed foods high in protein and unsaturated fats2.
To find out if that’s really true, Thomas and his colleagues performed CT scans on 137 mummies from four very different ancient populations: Egyptian, Peruvian, the Ancestral Puebloans of southwest America and the Unangans of the Aleutian Islands in Alaska. The Egyptians were artificially embalmed, whereas the other bodies were preserved naturally by very dry or very cold conditions.
The four groups had different lifestyles — the Ancestral Puebloans were forager–farmers, for example, whereas the Unangan were hunter–gatherers with an exclusively marine diet.
The researchers checked the mummies’ scans for calcified plaques in the wall of an artery or along the expected course of an artery. They diagnosed probable or definite atherosclerosis in 47 (34%) of the 137 mummies, and in all four populations, ranging from 25% of the 51 ancient Peruvians to 60% of the five Unangans.
Ancient disease
The researchers say that they found a level of disease equivalent to that in modern populations — a result Thomas describes as “a shock”.
The team previously had found atherosclerosis in a population of ancient Egyptians3, but experts, including Rosalie David at the KNH Centre for Biomedical Egyptology in Manchester, UK, argued that these were elite individuals, who probably ate a rich diet rivalling that of modern gluttons4.
“Now we’ve scanned the common man and woman and they’ve got the same disease,” says Thomas. Rather than excess cholesterol, he suggests that high levels of inflammation — caused by smoke inhalation or chronic infection, for instance — may have triggered the disease in these individuals.
Michael Rosenfeld at the University of Washington, Seattle, who studies the pathology of atherosclerosis, agrees that such factors can accelerate the course of the disease. But he points out that in animal studies, atherosclerosis does not develop without high levels of fat in the blood — whether as the result of bad diet or of bad genes.
He adds that the plaques seen in the mummies might have been caused by kidney disease or osteoporosis, rather than by atherosclerosis. “I still strongly believe that modern lifestyles have a lot to do with the development of atherosclerosis,” he says.
But Thomas says that cardiovascular disease should not now be seen as simply a consequence of an unhealthy lifestyle. “We’ve oversold the ability to stop heart disease,” he says. “We can slow it down, but to think we can prevent it is unrealistic.”
- Journal name:
- Nature
- DOI:
- doi:10.1038/nature.2013.12568
I do find the heart disease in the Unangan hunter-gatherer mummies interesting. The Unangans live in a VERY harsh environment that doesn't support much vegetation. And today we know from research that both high stress and low vegetable and fruit intake are associated with advanced atherosclerosis. We also know that atherosclerosis advances with age (although the severity and prevalence is much higher in industrialized populations).
So, what were these Unangan hunter-gatherers eating (or not eating)? Exactly how harsh is their environment? Were the five mummies examined representative of the entire Unangan population? And, more importantly, did the atherosclerosis found in these mummies actually result in heart attacks?
The reason I ask these questions is because many contemporary hunter-gatherers that continue to enjoy their traditional diets and lifestyles have very little prevalence of advanced atherosclerosis or cardiovascular disease (e.g., Masai, Kavirondo, Kitivans, !Kung, Solomon Islanders). And these modern hunter-gatherers eat varying degrees of saturated fats and animal meats. None are vegetarian as we define it. This puts a pretty large hole in the idea that animal fats (or plant-based saturated fats) and meats are the sole cause of cardiovascular disease in industrial populations.
This doesn't surprise me at all. The modern American diet and lifestyle (filled with nutrient-devoid foods, dietary toxins, and extreme inactivity) simply represent another way to develop cardiovascular disease. From my research, all you need to produce advanced atherosclerosis is chronic malnutrition, inflammation, endocrine disruption, and stress. All of these things could have been experienced by those living in ancient Egypt (especially the ruling elite).
For example, the ruling Egyptian elite would have been able to:
* Enjoy lots of expensive refined foods (e.g., honey, dried fruit, bread, cakes) and alcohol, both of which would displace more nutritious foods and cause varying degrees of malnutrition, chronic stress, and inflammation.
* Employ servants, allowing the ruling elite to be fairly inactive, which can cause chronic stress and inflammation.
* Participate in government management, which would have likely led to a lifestyle full of chronic emotional stress.
As for poor Egyptians, they would also have been able to consume bread, beer, and dried fruit. And all Egyptians may still have been developing the genetic ability to tolerate the gluten found in ancient varieties of wheat and barley, which could have caused malnutrition and chronic stress (much like that experienced today by those suffering from celiac disease and gluten intolerance).
So all the basic ingredients for advanced atherosclerosis (and cardiovascular disease) existed at that time, just like it does today in industrial populations.
(It is important to note that degenerative diseases [e.g., cardiovascular disease, cancer, diabetes] were very rare more than 100 years ago. However, after the Industrial Revolution made highly-refined, nutrient-devoid, toxin-laden foods cheap enough for everyone to enjoy, these degenerative diseases replaced infectious diseases as the top killers of Americans.)
I don’t believe this is as important as it first looks, that said its wonderful research.
I say this because I am not at all surprised that our ancestors diet was far from perfect and they had many diseases including atherosclerosis.
I don’t believe they had access to the required verity of nutrients that we have access to today.
I always say it’s the model of the mainly plant based diet that our ancestors had that is important not what was on their daily menu.
Do know all there is to know about atherosclerosis? No. Is diet an important factor in atherosclerosis? Yes. Does this research change this? No
Hadrian Roots2Life
It would be nice if they could have found a bunch of vegetarian mummies.
"Impact of consumption of animal products on cardiovascular disease, diabetes, and cancer in developed countries"
"If continued for a long time, oxidative stress induced by iron may lead to the development of many diseases, such as cardiovascular disease, type 2 diabetes, atherosclerosis, neurological disorders, and chronic inflammation.".
Can't prevent atherosclerosis? Simply not true. p.128 of T Colin Campbell's "The China Study" shows pictures of coronary artery before and after a low fat plant based diet. Not only is it easy to prevent atherosclerosis in most people, it can just as easily be reversed. By "easy" I mean that the method is cheap and universally available. There is no shortage of solid evidence to back the images in Campbell's book, but they are particularly persuasive!