The Paleo Diet – Did it ever Prevent Hardening of the Arteries?

Atherosclerosis, or “hardening of the arteries” is thought to be a disease of modern human beings and believed to be related to current diet and lifestyle factors, however its prevalence has now been documented in pre-industrial populations from four totally different regions of the world, with very different dietary intakes.

The “Paleo Diet” is a modern style of eating based on an ancient diet believed to have be eaten during the Paleolithic era — a period of about 2.5 million years which ended around 10,000 years ago with the development of agriculture and grain-based diets.  Proponents of this diet argue that modern human populations eating diets thought to be similar to those of Paleolithic societies are largely free of  “diseases of affluence”, including atherosclerosis (hardening of the arteries).

The “Paleo Diet” consists mainly of fish, grass-fed pasture raised meats, eggs, vegetables, fruit, fungi, roots and nuts (and excludes grains, legumes/pulses, dairy products, potatoes, refined salt, refined sugar and processed oils).

But is atherosclerosis a disease of modern human beings related to our current diet and lifestyle factors?  Its prevalence in pre-industrial populations from four totally different regions of the world with very different dietary intakes, has now been documented.

The Study

A new study published in the peer-review journal The Lancet (March 10, 2013) has obtained whole body CT scans of 137 mummies from four different geographical regions representing entirely different populations (ancient Egypt, ancient Peru, the Ancestral Puebloans of southwest America, and the Unangan of the Aleutian Islands) spanning more than 4000 years of history.  The ancient Egyptians and Peruvians were farmers, the ancestral Puebloans were forager-farmers, and the Unangans of the Aleutian Islands were hunter-gatherers without agriculture.  None of the cultures was known to be vegetarian and all were believed to be quite physically active.

Diagnosis of Atherosclerosis

For the purpose of the study, a diagnosis of atherosclerosis was made if a calcified plaque was seen in the wall of an artery and probable if calcifications were seen along the expected course of an artery

Findings of the Study

Researchers identified atherosclerosis in more than a third of the mummified specimens, raising the possibility that humans have a natural predisposition to the disease. In total, whole-body CT scans were performed on 137 mummies, including 76 ancient Egyptians, 51 ancient Peruvians, five ancestral Puebloans, and five Unangan hunter-gatherers. Probable or definite atherosclerosis was evident in 34% of the mummies; 29 ancient Egyptians, 13 ancient Peruvians, two ancestral Puebloans and three Unangan mummies.

Significance of these Findings

Atherosclerosis was considerably more common in ancient populations than previously believed.

In a presentation at a recent conference (March 9 – 11, 2013) at the American College of Cardiology 2013 Scientific Sessions in San Francisco, California led by Dr Randall Thompson (University of Missouri-Kansas City School of Medicine) and reported on Medscape Today News, March 16, 2013 the lead researcher of the study said;

our findings greatly increase the number of ancient people known to have atherosclerosis and show for the first time that the disease was common in several ancient cultures with varying lifestyles, diets, and genetics, across a wide geographical distance and over a very long span of human history. These findings suggest that our understanding of the causative factors of atherosclerosis is incomplete and that atherosclerosis could be inherent to the process of human aging.”

Ancient Paleo Diet

According to Dr. Thompson, the diets of these peoples were quite different from each other, as were the climates.  Local plant foods that were indigenous to each population group varied greatly over the wide geographical distance between these regions of the world. Fish and game were present in all of the cultures, but protein sources varied from domesticated cattle among the Egyptians to an almost entirely marine diet among the Unangans.”

Age and Cause of Death

Based on calculations using architectural changes in the bone structures, the average age of death was 43 years old and age was positively correlated  with atherosclerosis. Researchers note that all four populations lived at a time when infections would have been a common cause of death and the high level of chronic infection and inflammation might have promoted the inflammatory aspects of atherosclerosis.  These findings are consistent with the accelerated course of atherosclerosis seen in patients with rheumatoid arthritis and lupus today.

Conclusion

Atherosclerosis is not just a modern phenomenon; it was common in four pre-industrial populations across a wide span of human history, including a pre-agricultural hunter-gather population. The presence of atherosclerosis in pre-modern human beings suggests that the disease is an inherent component of human aging and not associated with any specific diet or lifestyle.

References

Atherosclerosis across 4000 years of human history: the Horus study of four ancient populations, The Lancet, Thompson RC, Allam AH, Lombardi GP et al, Published online March 10, 2013 http://dx.doi.org/10.1016/S0140-6736(13)60598-X

Medscape Today News, March 16, 2013