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Letter to the Editor, Public
Health Nutrition 
Paleo Longevity Redux
By
Jeff
D Leach
Sir,
Geoffrey Cannon1 repeats a
widespread affirmation that “paleolithic people usually did not survive
into what we call later middle age.” His underlying point, which is
widely shared among researchers and the public at-large, is that our
ancestors did not live long enough to develop cancer, heart disease and
other chronic illnesses. All of which forms the basis for the near
universal belief that ancient hunter-gatherers (our ancestors) really
were not healthier or fitter than us moderns, and therefore their
ancient dietary practices have little relevance to modern health,
well-being, and longevity.
On the initial point, Cannon is correct.
The average life span of our ancestors was short, compared to that of
modern humans in developed countries where one can expect to live into
their 60s, 70s and possibly early 80s, on “average.” Conversely, a
Neanderthal living in ancient Europe was lucky to live past her teens,
and if you lived to your mid-thirties you might have been considered old
in Ancient Egypt. More recently, the average life expectancy in the
United States in 1900 was 47.3 years. By 1935, that age had risen to 64
years and today that number hovers in the 70s for both women and men
(though women can expect to live a few years longer, on average).
The first problem with this thinking is
the “average life span” math is misleading and tells us very little
about the health and longevity of an individual, but rather gives us an
average age of death for a given group or population. For example, a
couple that lived to the ages of 76 and 71, but had one child that died
at birth and another at age two ([76+ 71 + 0 + 2] / 4), would produce an
average life span of 37.25. Using this methodology it is easy to see how
one would come to the conclusion that this group was not very healthy.
However, the precept that diet played a
significant role in the abbreviated average life span of our ancestors
is simply not true. There are few among us that believe are so-called
westernized diet of highly processed grains and added sugars and fats
are an optimal diet for anyone – past or present. Our soaring rates of
obesity and an ever-growing list of acute and chronic diseases –
occurring in alarming frequency among younger sections of the population
– speak to the discordance.
It is useful to point out that our species
reached our current anatomical and physiological standing nearly 200,000
years-ago2. That is, while components of what we discern as
hallmarks of behaviorally modern, such as language, art, trade networks,
and advanced weapons, have only occurred within the last 50,000 years,
the hardware has been in place for 150,000 years. While we may drive
around in hybrid cars today, we do so in very ancient bodies and with a
genome that was selected, for the most part, on a nutritional landscape
very different than the one we find ourselves today.
Before the advent and “widespread”
adoption of agriculture, which depending on where you lived occurred
between 1,000 and 9,000 years ago, humans organized in highly mobile
groups of dozens or a few hundred individuals. Archaeological data and
analysis of burial populations3 reveals that life was harsh
and dominated by warfare, strife, destruction, human trophy taking, and
the all-to-often practice of infanticide. All of these facts of ancient
life, in conjunction with the lack of simple antibiotics and modern
surgical practices, resulted in shorter average life spans than many of
us enjoy today.
As agriculture took hold around the globe
and groups settled down and built more permanent communities and
ultimately socio-politically complex civilizations, the more homogenous
and centralized food and water supply was easily contaminated by human
waste. While war and even larger massacres continued throughout the
agricultural revolution, tiny microbial killers took their share of
victims, especially among the young and undernourished, further reducing
the cyclical nature of the average life span. As European ships set sail
just a few centuries ago, new ills and evils further reduced the average
life span of populations they encountered – albeit punctuated.
As war, insanitariness, killer microbes,
and illness pulsed through humanity over time, our basic underlying
physiological and nutritional parameters have changed little in the last
few hundred thousand years. Our modern genome is in fact and ancient one
and natural and cultural selection has built it to last. Under optimal
nutritional conditions, such as those our genome evolved on, us modern
hunter-gatherers can live healthy and long lives. We need only look to
the modern Hunza of northern Pakistan or the southernmost Japanese state
of Okinawa to witness the longevity that our ancient genome is selected
for. With the threat of war and violence greatly reduced, and upon a
sound footing of a safe food supply, our ancient bodies can be healthy
well beyond “our best-before date” Cannon writes about. Based on a
low-calorie, high-fiber plant-based diet, a significant portion of the
population enjoy healthy and active lives into their 80s, 90s, and often
beyond 1004. Incredibly, the aged portions of these
populations have lower rates of obesity, heart disease, diabetes,
hypertension, high cholesterol, cancer, and other chronic diseases
compared to western populations.
The modern world owes much to antibiotics
and advanced surgical procedures of the last half century, resulting in
dramatic increases in average life span for much of the developed and
developing world. Though horrific events in Darfur and other African
states remind us how significant gains in average life span can easily
be erased. In Iraq, a male or female could expect to live to an average
age of 66.5 in 1990, but today following years of foreign occupation and
endless violence, life expectancy has dropped to a mere 59 for both
sexes – and slightly younger for males.
The self-confidence that comforts us today
as we review the average life span of our ancestors is misguided and
tenuous when viewed through the captivating haze of modern medicine that
literally props most of us up into our golden years. I doubt our
ancestors would call this living. While we may live longer than our
ancestors, we are in fact dying slower. So rather than rest on our
perceived cultural and medical success as it pertains to our longevity,
we should challenge ourselves and genomes to maximize our health for
optimal longevity. For those not trusting of the past and the
nutritional landscape upon which we evolved, our genetic cousins, the
Hunza and Okinawans, have shown us a way forward.
References
1 Cannon G. Out of the Box. Public Health
Nutrition 2007;
2 McDougall I., et al. Stratigraphic
Placement and Age of Modern Humans from Kibish, Ethopia. Nature 2005;
433:733-736.
3 Lawrence H. Keeley. War Before
Civilization. Oxford University Press, 1996.
4 John Robbins. “Healthy at 100” Random
House, 2006.
5 Population Reference Bureau. http://www.prb.org/Countries/Iraq.aspx.
Accessed June 9, 2007.
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