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.


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.


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

Medscape Today News, March 16, 2013

Health Benefits of Chocolate

While eating unlimited amounts of any calorically-dense food such as chocolate may increase the risk of overweight or obesity, consumption of chocolate, especially dark chocolate has been associated with several health benefits.

While eating unlimited amounts of any calorically-dense food such as chocolate may increase the risk of overweight or obesity, consumption of chocolate, especially dark chocolate has been associated with several health benefits.

What is chocolate?

Chocolate is a food produced from the seed of the tropical theobroma cacao tree.  The seeds of the cacao tree have an intense bitter taste and must be fermented to develop the flavor.  After fermentation the beans are dried then cleaned and roasted and then the shell is removed to produce cacao nibs. The nibs are then ground to cocoa mass; pure chocolate in rough form. Since the cocoa mass is usually liquefied then molded with or without other ingredients, it is called chocolate liquor.

The liquor also may be processed into two components: cocoa solids & cocoa butter.  The cocoa solids are responsible for the brown colour in dark and milk chocolate.  Dark chocolate contains primarily cocoa solids and cocoa butter, in varying proportions.  Milk chocolate combines cocoa solids, cocoa butter or other fat, and sugar as well as milk products such as milk powder or condensed milk.  White chocolate contains cocoa butter, sugar and milk solids but no cocoa solids and therefore really isn’t chocolate at all.

Chocolate as an ancient medicine

Recognition of cocoa’s health properties is nothing new. As far back as the 16th-century Spanish priests were aware of the nutritional properties of the highly prized Mayan cocoa drink and sanctioned its use as a food substitute during periods of fasting.

Chocolate and cardiovascular health

It is well known that certain plant polyphenols, in particular the flavonoids, act to lower the risk of both cardiovascular disease and cancer.  Flavanols are known to be present in red wine, tea and various fruits and berries but dark chocolate also contains large amounts of flavanols and has a cardio-protective role in the diet.

Chocolate and cough suppression

The presence of theobromine in chocolate has been shown to be more effective than codeine when it comes to suppressing a cough.  According to a 2005 study published in the FASEB Journal, researchers induced coughing in 10 healthy volunteers (using capsaicin from chili pepper) and then measured how much capsaicin was needed to induce a cough after subjects had taken theobromine (found in dark chocolate), codeine or a placebo.  In comparison with the placebo, when subjects had taken theobromine they needed around a third more capsaicin to produce a cough, whereas they needed only marginally higher levels of capsaicin after taking codeine.  Theobromine works by suppressing the activity of the vagus nerve which causes coughing.  Best of all, theobromine doesn’t produce any adverse effects on the cardiovascular or central nervous systems. Maria Belvisi, one of the study’s authors commented: “Normally the effectiveness of any treatment is limited by the dosage you can give someone. With theobromine having no demonstrated side effects in this study, it may be possible to give far bigger doses, further increasing its effectiveness”.

Chocolate’s beneficial effect on blood pressure

According to a 2002 study, eating just 30 calories a day of dark chocolate per day can help lower blood pressure without weight gain or other side effects.  This effect has been attributed to dark chocolates high content of cocoa polyphenols,

Researchers found that those who ate 6.3 gm of dark chocolate per day of dark chocolate (about 30 calories and 30 mg of polyphenols) saw their average systolic blood pressure drop by 2.9 mm Hg and diastolic BP by 1.9 mm Hg.  Those diagnosed with hypertension (high blood pressure) had their blood pressure drop by 18% as a result of consuming 6.3 gm of dark chocolate. Furthermore, none of the subjects in the study experienced any changes in body weight, blood lipids (cholesterol) or blood glucose (sugar) levels.

Subjects that ate the same amount of white chocolate (which contains no cocoa and therefore no polyphenols) had no change in their systolic or diastolic blood pressure.  Although the magnitude of the blood pressure reduction was small, the effects are clinically noteworthy.

On a population basis, it has been estimated that a 3-mm Hg reduction in systolic blood pressure would reduce the relative risk of death by stroke by 8 % and of death from coronary artery disease by 5%, and of all-cause death by 4%.

It is proposed by one of the authors of a 2006 study (Dr. Naomi Fisher) that the decrease in arterial stiffness noted in subjects after consuming 100 gm of dark chocolate was due to the effect of the flavonoids in the cocoa acting on an enzyme called nitric oxide synthase; resulting in dilatation of blood vessels,  improve kidney function and lower blood pressure.

Chocolate toxic to pets?

Cocoa solids (found in dark chocolate and milk chocolate) contains alkaloids such astheobromine and phenethylamine which, as noted above have some positive physiological benefits in humans but it is the presence of theobromine which renders it toxic to some animals, including dogs and cats.  Because white chocolate does not contain any cocoa solids, and thus no theobromine, it can be safely eaten by animals.

Other Benefits of Chocolate:

Chocolate also holds benefits apart from protecting your heart:

1. It stimulates endorphin production, which gives a feeling of pleasure.

2. It contains serotonin, which is a neurotransmitter that has an anti-depressant effect

3. It contains small quantities of phenylethylamine, another neurotransmitter that creates feelings of attraction and excitement in the brain’s pleasure centre. (Maybe that’s where chocolate came to have a reputation as an aphrodisiac?)

4. It tastes good!

A little goes a long way

Chocolate is still a high-calorie, high-fat food. Most of the studies done used no more than 100 grams, or about 3.5 ounces, of dark chocolate a day to get the benefits. One bar of dark chocolate has around 400 calories. If you eat half a bar of chocolate a day, you must balance those 200 calories by eating less of something else.

To indulge a chocolate habit without regrets, choose dark varieties containing at least 70 % cocoa solids and check low levels of cocoa butter. Try to make a little go a long way.  Research indicates that you get maximum benefit with fewer ill effects from just one or two squares of dark chocolate per day.


Fisher ND, Hollenberg NK. Aging and vascular responses to flavanol-rich cocoa. J Hypertens. 2006 Aug; 24(8):1575-80.

Francene M Steinberg, Monica M Bearden, Carl L Keen, Cocoa and chocolate flavonoids: Implications for cardiovascular health, JADA 2003; 103(2)215-223,

Taubert D, Renate R, Clara L, et al. Effects of Low Habitual Cocoa Intake on Blood Pressure and Bioactive Nitric Oxide., JAMA 2010; 298 (1): 49-60.

Usmani OS, Belvisi MG, Patel HJ et al, The FASEB  Journal 2005 Vol 19, pgs 231-233Theobromine inhibits sensory nerve activation and cough