By Craig Weatherby
Growing evidence indicates that the so-called Paleolithic or Stone Age diet is beneficial.
Loren Cordain, Ph.D. is the leading researcher into and popularizer of the increasingly fashionable “paleo diet”.
As he writes, the “… Paleo Diet mimics the types of foods every single person on the planet ate prior to the Agricultural Revolution (a mere 333 generations ago).”
Why is the paleo diet is good for us?
As Cordain says, “These foods (fresh fruits, vegetables, meats, and seafood) are high in the beneficial nutrients … that promote good health, and are low in the foods and nutrients … that frequently may cause weight gain, cardiovascular disease, diabetes, and numerous other health problems.”
Dr. Cordain notes that despite the diet's heavy reliance on animal foods, it would not necessarily cause unfavorable changes to blood lipid (fat, cholesterol) profiles, for three reasons.
First, he stresses the lipid-moderating effects of the Paleo diet's relatively high protein intakes (19-35 percent of calories) and relatively low level of carbohydrates (just 22-40 percent of calories).
(Excess intake of carbohydrates exerts generally pro-inflammatory and pro-diabetic effects, while raising blood fat levels and promoting unhealthful cholesterol profiles.)
Second, although fat intake (28-58 percent of calories) in the Stone Age was similar to or higher than that found in Western diets, it featured important qualitative differences in fat intake.
Third, the Paleo diet's relatively high levels of unsaturated versus saturated fatty acids – and a far lower omega-6/omega-3 fat intake ratio – would have discouraged cardiovascular disease (Cordain L et al. 2002; Kuipers RS et al. 2010).
Other hallmarks of the Paleo diet – high intakes of antioxidants, fiber, vitamins and phytochemicals along with a low salt intake – may have worked synergistically with lifestyle characteristics (more exercise, less stress, and no smoking) to further deter development of cardiovascular disease (Cordain L et al. 2002; O'Keefe JH Jr, Cordain L 2004).
In other words, we need to largely replace “empty calorie” processed foods, sugar, and refined carbs (white bread, pasta) with nutrient-dense plant foods and high-protein, good-fat foods like fish and forage-fed livestock and poultry.
Why has this idea been easily passing the evidentiary test?
The human genome developed in response to a diet of “wild” forage foods – nuts, greens, seafood, meat, and edible roots – not agricultural fare.
And paleo diet advocates even say we should avoid or minimize whole grains, given their absence from the prehistoric human diet.
We find the evidence in favor of the paleo diet pretty compelling … but intriguing finds suggest that the eating plan can't guarantee freedom from heart disease.
Cardiovascular disease found in mummies worldwide
California-based academic researchers performed CT scans of 137 mummies from across four continents and found artery plaque in every population studied (Thompson RC et al. 2013).
Their survey included Paleolithic people ranging from pre-agricultural hunter-gatherers in the Aleutian Islands to the ancient Pueblo culture of the American southwest (Colorado River basin).
Like nearly 4.6 million Americans today, ancient hunter-gatherers also suffered from clogged arteries … though likely at a lower rate.
About 38 percent of the Egyptians and 29 percent of the others had definite or probable evidence of atherosclerosis, in the form of arterial calcium deposits.
Prior studies revealed signs of atherosclerosis in mummies from Egypt, where mummification in Egypt occurred mainly among the elite … whose diet and lifestyle was probably quite different from that of the lower classes.
So unsurprisingly, this study also found atherosclerosis in Egyptian mummies … to be exact, it showed up in 29 of the 76 examined.
However, the team also found atherosclerosis in 13 of 51 Peruvian remains (dated from A.D. 200 to 1500), two of five ancestral Pueblans (1500 B.C. to A.D. 500), and three of five Aleutian Islanders … who lived in the 19th and early 20th centuries but ate diets relatively close to the Paleolithic model.
Significantly, the mummies' longevity was linked to atherosclerosis: the average age at death was 43 years for mummies with atherosclerosis versus 32 years for those without it.
Atherosclerosis was equally common in male and female mummies. And affirming the link, calcification of arteries more pronounced in the mummies that were older at time of death.
Genes can play a dominating role in cardiovascular disease
Apparently, the plaque build-up that causes blood clots, heart attacks and strokes can occur even in the absence of junky diets and couch potato habits.
Modern diets and lifestyles tend to be pro-inflammatory and pro-diabetic … effects that can speed buildup of arterial plaque, while making it less stable and more likely to shed killer clots.
But the prevalence of atherosclerosis across human history suggests that even a generally good “paleo-like” diet can be outweighed by atherosclerosis risk factors that also existed way back when … like inflammation, infection, aging, and a genetic predisposition to plaque formation (i.e., atherosclerotic APOE gene variants).
For example, tooth decay and gum disease can lead to cardiovascular disease ... and ancient people surely had both afflicitions ... though likely much less of either than some moderns, who eat far sweeter, starchier diets.
“This is not a disease only of modern circumstance but a basic feature of human aging in all populations,” said Caleb Finch, Ph.D., of the USC Davis School of Gerontology.
“Turns out even a Bronze Age guy from 5,000 years ago had calcified, carotid arteries,” Finch said, referring to Otzi the Iceman, a natural mummy who lived around 3200 BCE and was discovered frozen in a glacier in the Italian Alps in 1991.
With Gregory Thomas of Long Beach Memorial, Finch was part of a team that previously showed Egyptian mummies had calcified patches on their arteries indicative of advanced atherosclerosis (from the Greek arthero, meaning “gruel” and scler, meaning “hard”).
But ancient Egyptians tended to mummify only royalty or those who had privileged lives.
The new study – led by Thomas and Randall Thompson of Saint Luke's Mid America Heart Institute – examined ancient mummies from four drastically different climates and diets: Peru, the American southwest, the Aleutian Islands, and Egypt.
“Our research shows that we are all at risk for atherosclerosis, the disease that causes heart attacks and strokes – all races, diets and lifestyles,” said Thomas.
“Because of this we all need to be cautious of our diet, weight and exercise to minimize its impact. The data gathered about individuals from the pre-historic cultures … are forcing us to think outside the box and look for other factors that may cause heart disease.”
“We found that heart disease is a serial killer that has been stalking mankind for thousands of years,” Thompson said. As he noted, “In the last century, atherosclerotic vascular disease has replaced infectious disease as the leading cause of death across the developed world.”
“A common assumption is that the rise in levels of atherosclerosis is predominantly lifestyle-related, and that if modern humans could emulate pre-industrial or even pre-agricultural lifestyles, that atherosclerosis, or at least its clinical manifestations, would be avoided.”
“Our findings seem to cast doubt on that assumption, and at the very least, we think they suggest that our understanding of the causes of atherosclerosis is incomplete, and that it might be somehow inherent to the process of human aging,” Thompson added. (USC 2013)
The international team will next seek to biopsy ancient mummies to get a better understanding of the role chronic infection, inflammation and genetics in promoting the prevalence of atherosclerosis.
“Atherosclerosis starts very early in life. In the United States, most kids have little bumps on their arteries. Even stillbirths have little tiny nests of inflammatory cells. But environmental factors can accelerate this process,” Finch said, pointing to studies that show larger plaques in children exposed to household tobacco smoking or who are obese (USC 2013).
Abdelfattah A, Allam AH, Wann S, Thompson RC, Abdel-Maksoud G, Badr I, Amer HA, El-Din AE, Finch CE, Miyamoto MI, Sutherland L, Sutherland JD, Thomas GS. Atherosclerotic cardiovascular disease in Egyptian women: 1570 BCE-2011 CE. Int J Cardiol. 2012 Feb 20. [Epub ahead of print]
Allam AH, Thompson RC, Wann LS, Miyamoto MI, Nur El-Din Ael-H, El-Maksoud GA, Al-Tohamy Soliman M, Badr I, El-Rahman Amer HA, Sutherland ML, Sutherland JD, Thomas GS. Atherosclerosis in ancient Egyptian mummies: the Horus study. JACC Cardiovasc Imaging. 2011 Apr;4(4):315-27. doi: 10.1016/j.jcmg.2011.02.002.
Allam AH, Thompson RC, Wann LS, Miyamoto MI, Thomas GS. Computed tomographic assessment of atherosclerosis in ancient Egyptian mummies. JAMA. 2009 Nov 18;302(19):2091-4. doi: 10.1001/jama.2009.1641.
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Kuipers RS, Luxwolda MF, Dijck-Brouwer DA, Eaton SB, Crawford MA, Cordain L, Muskiet FA. Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet. Br J Nutr. 2010 Dec;104(11):1666-87. doi: 10.1017/S0007114510002679. Epub 2010 Sep 23.
O'Keefe JH Jr, Cordain L. Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: how to become a 21st-century hunter-gatherer. Mayo Clin Proc. 2004 Jan;79(1):101-8. Review.
University of Southern California (USC). Mummy CT scans show preindustrial hunter gatherers had clogged arteries. Accessed at http://www.eurekalert.org/pub_releases/2013-03/uosc-mcs030813.php
Thompson RC et al. Atherosclerosis across 4000 years of human history: the Horus study of four ancient populations. The Lancet - 11 March 2013. DOI: 10.1016/S0140-6736(13)60598-X. Accessed at http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60598-X/fulltext