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A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilisation

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Evolutionary medicine acknowledges that many chronic degenerative diseases result from conflicts between our rapidly changing environment, our dietary habits included, and our genome, which has remained virtually unchanged since the Palaeolithic era. Reconstruction of the diet before the Agricultural and Industrial Revolutions is therefore indicated, but hampered by the ongoing debate on our ancestors' ecological niche. Arguments and their counterarguments regarding evolutionary medicine are updated and the evidence for the long-reigning hypothesis of human evolution on the arid savanna is weighed against the hypothesis that man evolved in the proximity of water. Evidence from various disciplines is discussed, including the study of palaeo-environments, comparative anatomy, biogeochemistry, archaeology, anthropology, (patho)physiology and epidemiology. Although our ancestors had much lower life expectancies, the current evidence does neither support the misconception that during the Palaeolithic there were no elderly nor that they had poor health. Rather than rejecting the possibility of 'healthy ageing', the default assumption should be that healthy ageing posed an evolutionary advantage for human survival. There is ample evidence that our ancestors lived in a land-water ecosystem and extracted a substantial part of their diets from both terrestrial and aquatic resources. Rather than rejecting this possibility by lack of evidence, the default assumption should be that hominins, living in coastal ecosystems with catchable aquatic resources, consumed these resources. Finally, the composition and merits of so-called 'Palaeolithic diets', based on different hominin niche-reconstructions, are evaluated. The benefits of these diets illustrate that it is time to incorporate this knowledge into dietary recommendations.
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A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise
for the prevention and treatment of diseases of civilisation
Remko S. Kuipers
1
, Josephine C. A. Joordens
2
and Frits A. J. Muskiet
1
*
1
Laboratory Medicine, University Medical Center Groningen (UMCG), Groningen, The Netherlands
2
Human Origins Group, Faculty of Archaeology, Leiden University, Leiden, The Netherlands
Abstract
Evolutionary medicine acknowledges that many chronic degenerative diseases result from conflicts between our rapidly changing environ-
ment, our dietary habits included, and our genome, which has remained virtually unchanged since the Palaeolithic era. Reconstruction of
the diet before the Agricultural and Industrial Revolutions is therefore indicated, but hampered by the ongoing debate on our ancestors’
ecological niche. Arguments and their counterarguments regarding evolutionary medicine are updated and the evidence for the long-
reigning hypothesis of human evolution on the arid savanna is weighed against the hypothesis that man evolved in the proximity of
water. Evidence from various disciplines is discussed, including the study of palaeo-environments, comparative anatomy, biogeochemistry,
archaeology, anthropology, (patho)physiology and epidemiology. Although our ancestors had much lower life expectancies, the current
evidence does neither support the misconception that during the Palaeolithic there were no elderly nor that they had poor health. Rather
than rejecting the possibility of ‘healthy ageing’, the default assumption should be that healthy ageing posed an evolutionary advantage for
human survival. There is ample evidence that our ancestors lived in a land water ecosystem and extracted a substantial part of their diets
from both terrestrial and aquatic resources. Rather than rejecting this possibility by lack of evidence, the default assumption should be that
hominins, living in coastal ecosystems with catchable aquatic resources, consumed these resources. Finally, the composition and merits of
so-called ‘Palaeolithic diets’, based on different hominin niche-reconstructions, are evaluated. The benefits of these diets illustrate that it is
time to incorporate this knowledge into dietary recommendations.
Key words: Palaeolithic nutrition: Disease prevention: Disease treatment: Dietary recommendations: Evolutionary medicine:
Healthy ageing
Introduction
In the Origin of Species
(1)
, Darwin recognised that there
are two forces of evolution, i.e. natural selection and the
conditions of existence, where the latter was considered
the most powerful
(2)
. For example, important steps in evo-
lution are the origin of eukaryotic life approximately
1·6–2·7 billion years ago
(3,4)
and the appearance of photo-
synthetic cyanobacteria that began to oxygenate the
atmosphere about 2400 million years ago (Mya)
(5)
. However,
there was relatively little alteration in the design of life
forms before the Cambrian explosion about 600 Mya. Only
when the oxygen tension in the atmosphere rose above the
Pasteur point did aerobic metabolism become thermo-
dynamically possible
(6)
, resulting in an explosion from
simple prokaryotics to a diversity of eukaryotic life forms
(7)
.
During the past millions of years of evolution, with rela-
tively little alteration in life forms and environmental circum-
stances, the human genome has become optimally adapted
to its local environment
(8 – 11)
. In other words, our genome
may have reached a state of homeostasis, defined as the
‘optimal interaction between environment and genome’ or
‘nature in balance with nurture’, to support optimal survival
for reproductive success. The aetiologies of many typically
Western diseases, also known as diseases of affluence or
civilisation, have been attributed to the disturbance of this
delicate balance, secondary to the rapid changes in the con-
ditions of existence, while our genome has remained basi-
cally unchanged since the beginning of the Palaeolithic
era. The former include changes in physical activity, stress,
sleep duration, environmental pollution and others
(12,13)
,
*Corresponding author: Dr Frits A. J. Muskiet, fax þ31 50 361 2290, email f.a.j.muskiet@umcg.nl
Abbreviations: AA, arachidonic acid; ALA, a-linolenic acid; en%, percentage energy; EQ, encephalisation quotient; Kya, thousand years ago; LA, linoleic
acid; MCSFA, medium-chain SFA; Mya, million years ago; RAR, retinoic acid receptor; RXR, retinoid X receptor; TR, thyroid hormone receptor; VDR,
vitamin D receptor.
Nutrition Research Reviews (2012), 25, 96–129 doi:10.1017/S0954422412000017
qThe Authors 2012
Nutrition Research Reviews
but one of the most rapidly changing conditions of existence
has been the human diet.
Since the onset of the Agricultural Revolution, some 10
thousand years ago (Kya), and notably in the last 200
years following the start of the Industrial Revolution,
humans have markedly changed their dietary habits. Con-
sequently, it has been advocated that the current pandemic
of diseases of civilisation results in part from the mismatch
between the current diet and our Palaeolithic genome. In
other words, ‘we are what we eat, but we should be
what we ate’
(14,15)
. The ensuing poorly adapted phenotype
may find its origin as early as in the fetal period
(16,17)
and
possibly as far back as in the maternal grandmother’s
womb
(18)
. This phenotype might be laid down in, inher-
ently labile, epigenetic marks that are meant for the
short- and intermediate-term adaptation of a phenotype
to the conditions of existence. With clear evolutionary
advantages they may become transmitted to the next
generations as a memory of the environmental conditions
that can be expected after birth
(19)
. They thereby give
rise to a seemingly high contribution of genetics in some
of the associated ‘typically Western’ degenerative diseases,
which are in fact complex diseases that by definition do
not inherit by Mendel’s law, illustrating that epigenetic
marks can also become erased.
From a pathophysiological point of view, the poorly
adapted phenotype in Western countries, ensuing from
the conflict between the changing lifestyle and our Palaeo-
lithic genome, centres on chronic low-grade inflammation
and the metabolic syndrome (also named the insulin resist-
ance syndrome), which are risk factors for many of the dis-
eases and conditions typical for affluent countries, such as
CVD, type 2 diabetes mellitus, osteoporosis, certain types
of cancer (notably colon, breast, prostate), fertility pro-
blems (polycystic ovary syndrome), pregnancy compli-
cations (gestational diabetes, pre-eclampsia), some
psychiatric diseases (major and postpartum depression,
schizophrenia, autism) and neurodegenerative diseases
(Alzheimer’s disease, Parkinson’s disease)
(20 – 22)
. The
genetically determined flexibility to adapt to a changing
environment appears to have been exceeded and the
genetically most vulnerable have become sick first, but ulti-
mately all individuals will become sick with increasing
dose and exposure time.
Environment, nutrients and their interaction with the
genome
Adjustment of the DNA base sequence is a slow process
that in an individual cannot support adaptation to environ-
mental changes occurring at intermediate or rapid pace.
Flexibility for rapid adaptation is provided by genetically
encoded mechanisms that allow adjustment of phenotype
by epigenetics and by the interaction of the environment
with sensors, such as those of the sensory organs, but
also by the many that remain unnoticed
(23 – 25)
. The role
of nutrients in (epi)genetics and their direct interaction
with the genome have become increasingly acknow-
ledged
(26)
. Examples of such nutrients are iodine, Se,
vitamins A and D, and n-3-fatty acids, which are direct or
indirect ligands of the thyroid hormone receptor (TR),
retinoid X receptor (RXR), retinoic acid receptor (RAR),
vitamin D receptor (VDR) and PPAR. Homodimerisation
and heterodimerisation of these receptors facilitate gene
transcription and thereby keep our phenotype optimally
adapted to the reigning conditions of existence. The roles
of these nutrients, their respective receptors and the
interaction between their receptors are indicative of the
importance of their dietary presence and of a certain
balance between their dietary intakes to arrive at optimal
interaction with the genome. Lessons for this optimal
interaction, and hence for the development of randomised
controlled trials aiming at the study of diet or lifestyle,
rather than single nutrients, might derive from knowledge
on human evolution and the conditions of existence to
which our ancestors have been exposed. These lessons
might provide us with valuable information on what we
should genuinely define as a ‘healthy diet’.
Evolutionary medicine
The concept that a thorough understanding of evolution
is important in the prevention and treatment of (human)
diseases has long been recognised. For example, in the
early 1960s it was stated that ‘nothing in biology makes
sense except in the light of evolution’
(27)
, while in ethol-
ogy, a distinction was made between proximate and ulti-
mate (also named evolutionary) causes
(28)
. Proximate
explanations provide a direct mechanism for certain beha-
viour in an individual organism. They explain how biomo-
lecules induce certain behaviour or, for example, an
allergic reaction. Proximate explanations, however, pro-
vide insufficient information to answer the question why
this behaviour or this allergic reaction occurred. Ultimate
explanations provide answers explaining why things
happen from an evolutionary point of view. Many, if not
all, diseases can become explained by both proximate
and ultimate explanations. The science searching for the
latter explanations has become known as ‘evolutionary
medicine’. Unfortunately, modern medicine deals mostly
with proximate explanations
(29,30)
, while ultimate expla-
nations seem more prudent targets for long-time disease
prevention
(29)
.
The term ‘evolutionary medicine’ (also named Darwinian
medicine) was launched by Randolph M. Nesse and George
C. Williams
(31,32)
. They provided evolutionary answers
for the understanding of human diseases. Many diseases
do not result from a single biological, anatomical or phy-
siological abnormality, but rather from a complex web
of interactions. They often reflect the collateral damage
of the survival and reproduction strategies of our genes
and the genes of other organisms in our environment.
Palaeolithic nutrition for disease prevention 97
Nutrition Research Reviews
The resulting disease manifestations include the outcomes
of human defence mechanisms to clear foreign pathogens
and the collateral damage of conflicts and trade-offs
between humans and foreign invaders. Examples often
overlooked are coincidence, in which diseases may result
from imperfections of human evolution, and exaptation, in
which a feature is not acquired in the context of any function
to which it might eventually be put
(33)
. For example, the
equilibrium between the not yet full-grown, but yet relatively
large, brain of a newborn and the small birth canal in its
turn is constrained by an upright posture and provides
an example of a trade-off in human evolution. The location
of the birth canal in its turn provides an example of an
evolutionary coincidence that urges to deal with an, in
retrospect, imperfect evolutionary design. These examples
illustrate that evolution builds on the past: it is not possible
to start a completely new design from scratch, which
argues against ‘intelligent design’. The most important
example of an evolutionary explanation for human disease,
however, comes from the mismatch between our slowly
adapting genome and the rapidly changing environment,
notably our diet.
Evolutionary medicine argues that the chronic degenera-
tive diseases causing most morbidity and mortality in afflu-
ent countries occur because of the current mismatch
between the rapidly changing conditions of existence
and our Palaeolithic genome
(34)
. These mismatches will
persist, notably in the light of our long generation time.
The genetic adjustments needed to adapt to the new
environment are also unlikely to occur, since the mismatch
exerts little selection pressure. That is, they do not cause
death before reproductive age, but rather reduce the num-
bers of years in health at the end of the life cycle
(35)
. Con-
sequently, evolutionary medicine acknowledges a return to
the lifestyle before the onset of the Agricultural Revolution
as translated to the culture of the 21th century and as
popularised by the expression: ‘how to become a 21th cen-
tury hunter–gatherer’
(36)
. Skeptics of evolutionary medi-
cine often raise the intuitive criticism that the human
ancestor had a very short life expectancy compared with
contemporary individuals
(35)
. Consequently, they argue,
there was no selection pressure on longevity or ‘healthy
ageing’, since there were virtually no old people, while
the few individuals reaching old (for example, postmeno-
pausal) age provided no evolutionary benefit to younger
individuals who were still able to reproduce. The counter-
argument is multilevelled.
Arguments and counterarguments in evolutionary health
promotion
It needs to be emphasised that evolutionary medicine pre-
dicts no further increase in life expectancy, but rather a
decrease in the numbers in deteriorating health at the
end of the life cycle. It has been estimated that the com-
plete elimination of nine leading risk factors in chronic
degenerative diseases would increase life expectancy at
birth by only 4 years, since these diseases only affect
late-life mortality
(37)
. Second, the increased life expectancy
at present originates mostly from the greatly diminished
influence of some unfavourable conditions of existence,
including (childhood) infections, famine, homicide and
tribal wars
(34,38)
secondary to the high levels of medical
sciences and continuing civilisation. Thus, to achieve the
average life expectancy of 40 years in a present-day
hunter–gatherer society, for every child that does not sur-
vive beyond 1 year of age, another should reach the age of
80 years. In fact, about 20 % of modern hunter – gatherers
reach at least the age of 60 years
(39 – 41)
. In other words,
the popular argument that very few individuals in these
societies live past 50 years
(35)
is unsupported by ethno-
graphic data. The third, often raised, argument is that
due to the higher life expectancy in present-day humans,
it is invalid to compare the mortality figures for cancer
and degenerative disease of present-day huntergatherers
(with low life expectancies) with those of Western popu-
lations (with a life expectancy of 80 years). However,
early biomarkers of degenerative diseases such as obesity,
high blood pressure, atherosclerosis and insulin resistance
are also less common in younger, age-matched, members
of present huntergatherer compared with members of
affluent societies
(9,42)
, while measurements indicative for
‘good health’ such as muscular strength and aerobic
power are more favourable in the former
(43)
. Moreover,
even the oldest individuals in huntergatherer societies
appear virtually free from chronic degenerative dis-
eases
(44 – 46)
. A fourth counterargument against the assump-
tion that our human ancestors before the Agricultural
Revolution died at a young age derives from archaeological
records. After the transition from hunting and gathering to
farming about 10 Kya, life expectancy dropped from about
40 years (as it is in recently studied hunter gatherers,
but also was among students of the Harvard College
Class born in 1880
(47)
) to about 20 years
(48 – 50)
. This see-
mingly evolutionary disadvantage, secondary to a decrease
in nutritional quality, is substantiated by a decrease in gen-
eral health that has become noticeable from a decrease
in final height, while skeletal markers of infection and
nutritional stress became more common in archaeological
finds
(49 – 52)
. These setbacks were eliminated by a net
increase in population growth, secondary to an increased
productivity per land area that resulted in more energy
intake per capita. Life expectancy remained stable through-
out the Neolithic until the late 18th century, seldom
exceeding 25 years in ‘civilised’ nations
(35)
. From this
time, improvements in hygiene, food production and
manufacturing, energy generation, per capita income,
shelter, transportation, clothing and energy intakes sub-
stantiated an increase to and beyond the life expectancy
that prevailed before the onset of the Agricultural Revo-
lution. Greater energy availability enhanced, for example,
the energy requirements of the immune system and for
R. S. Kuipers et al.98
Nutrition Research Reviews
reproduction, both improving longevity
(35,53)
. Importantly,
it was concluded that medical treatments had little impact
on mortality reduction, while public health achievements
(sanitation, food and water hygiene, quarantine and
immunisations) have critically improved life expectancy.
The fifth counterargument is that old people do provide
an evolutionary benefit to the younger generations.
Male fertility remains largely intact and male provisioning
might help in the problem of high female reproductive
costs, although the latter is contested
(54,55)
. The benefits
of older females have been put forward in the grand-
mother hypothesis. This hypothesis, in which the presence
of older females within a certain group benefits the
reproductive success of their offspring, is supported by
studies in human huntergatherer
(56 – 62)
and primate
societies
(56,60,63)
. Interestingly, the fitness benefits of
grandmothering proved insufficient to fully explain the
evolution of increased longevity
(62)
, suggesting that other
evolutionary benefits, such as grandfathering, might also
be involved in the long reproductive and non-reproduc-
tive lifespan of Homo sapiens. A recent analysis supports
such benefits for both older males and females, since
the presence of post-reproductive women increased the
numbers of newborns by 2·7 %, while 18·4 % of the infants
in a polygamous society in rural Africa were sired by
males aged 50 years and above
(64)
. In support of the state-
ment that ‘nothing in biology makes sense except in the
light of evolution’ we therefore conclude that, unless
proven otherwise, the presence of a substantial pro-
portion of older males and postmenopausal females in
hunter–gatherer, in contrast to primate societies, should
be considered as proof for the evolutionary benefit
that these individuals are to their progeny. Finally, we
propose that this assumption would only be convincible
if these individuals were reasonably fit, thereby support-
ing the concept of healthy ageing. Hence, healthy
ageing seems both supported by ethnographic data and
its benefit to huntergatherer societies. Other commonly
raised arguments against the genomeenvironment mis-
match hypothesis are the potential genetic changes since
the Agricultural Revolution, the heterogeneity of ancestral
environments and innate human adaptabilty
(35)
. Counter-
arguments to these critics have been discussed in great
detail elsewhere
(35)
.
In the present review, a multidisciplinary approach is
used, including palaeo-environmental reconstruction, com-
parative anatomy, biogeochemistry, archaeology, anthro-
pology, (patho)physiology and epidemiology, to assess
the characteristics of the ecosystem that supported
human evolution. Based on this assessment, an approxi-
mation is made of the dietary composition that derives
from this ecosystem. Finally, the potential benefit of a
return to this ‘Palaeolithic diet’ is discussed and an
update is provided for the evidence for the positive
health effects of these diets.
Human evolution
Hominins are defined as members of the taxon Hominini,
which comprises modern Homo sapiens and its extinct
relatives over the past about 7 million years. The oldest-
known hominins (Fig. 1) are Sahelanthropus tchadensis
from Chad (about 7 Mya
(65)
) and Orrorin tugenensis
from Kenya (about 65·7 Mya
(66)
). The next oldest are
Ardipithecus kadabba (Ethiopia, about 5·8 Mya
(67)
)and
A. ramidus (Ethiopia, about 4·4 Mya
(68)
), Australopithecus
anamensis (Kenya, about 4·1–3·9 Mya
(69)
), Au. afarensis
(Ethiopia, Tanzania and maybe Kenya, 3·6–3·0
Mya
(70,71)
), Au. bahrelghazali (Chad, about 3·5 Mya
(72)
),
Kenyanthropus platyops (Kenya, about 3·5 Mya
(73)
),
Au. garhi (Ethiopia, about 2·5 Mya
(74)
) and Au. africanus
(South Africa, about 2·9–2·0 Mya
(75)
). From these earliest
hominins evolved the genera Paranthropus (three known
subspecies) and Homo. The earliest species that have
been designated Homo are Homo rudolfensis,Homo
habilis and Homo erectus sensu lato including H. ergaster
(Eastern Africa, about 21.8 Mya): these in turn are the
presumed ancestors of Asian H. erectus,H. heidelbergensis
(Africa, Eurasia 0·6–0·3 Mya), H. neanderthalensis
(Eurasia, 0·4–0·03 Mya) and H. sapiens (from about 0·2
Mya onwards)
(76 – 78)
. The recently discovered H.floresien-
sis (0·095–0·013 Mya
(79)
) and the previously unknown
hominins from Denisova Cave (about 0·05– 0·03 Mya
(80)
)
show that in the recent past several different hominin
lines co-existed with modern humans.
Africa is now generally accepted as the ancestral home-
land of Homo sapiens
(77,81,82)
. In several subsequent out-
of-Africa waves
(83)
, hominins of the genus Homo colonised
Asia, Australia, Europe and finally the Americas (Fig. 2).
Archaic Homo species reached as far as the island of Flores
in South-East Asia, East China and Southern Europe
(Spain). Homo heidelbergensis remains were found in
Africa, Europe and Eastern Asia, while Homo neandertha-
lensis was restricted to Europe, Western Asia and the
Levant. At last, in the later out-of-Africa diaspora starting
about 100 Kya, Homo sapiens finally reached Australia and
the Americas, while probably replacing earlier hominins
in Africa, Europe and Asia that had left during the earlier
out-of-Africa waves. However, there remains some
debate
(82,84 – 86)
whether or not the gene pool of archaic
hominins contributed to that of modern humans. In the
replacement theory, archaic hominins make no contribution
to the gene pool of modern man, whereas in the hybridis-
ation theories (either through assimilation or gene flow),
newly arriving hominins from the later out-of-Africa wave
mixed with archaic predecessors. Current evidence from
DNA analyses supports the concept that the gene pool of
archaic hominins, notably Neanderthals
(87)
, but also Deniso-
vans
(80)
contributed to the gene pool of Homo sapiens.
The African cradle of humankind is supported by
micro-satellite studies
(88)
that reveal that within popu-
lations the genetic variation decreases in the following
Palaeolithic nutrition for disease prevention 99
Nutrition Research Reviews
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Mya Mya
H. neanderthalensis
H. sapiens
H. heidelbergensis
H. floresiensis
H. erectus
H. mauritanicus/antecessor
H. habilis
Au. sediba
H. rudolfensis
Au. africanus Au. garhi
Au. afarensis
K. platyops
Au. anamensis
O. tugenensis
S. tchadensis
Ar. kadabba
Ar. ramidus
Au. bahrelghazali
P. aethiopicus
P. boisei
P. robustus
H. ergaster
Fig. 1. Scheme of the possible phylogenetic relationships within the family Hominidae. Note that at many time points of evolution, several different hominin species
coexisted. Mya, million years ago; H.,Homo;Au.,Australopithecus;K.,Kenyanthropus;P.,Paranthropus;Ar.,Ardipithecus;O.,Orrorin;S.,Sahelanthropus.q
Ian Tattersall, with permission
(76)
.
R. S. Kuipers et al.100
Nutrition Research Reviews
order: sub-Saharan Africa .Eurasia .East Asia .
Oceania .America, with the huntergatherer Hadzabe
of Tanzania separated from the Juj’hoansi (previously
called !Kung) from Botswana by a genetic distance greater
than between any other pair of populations
(89)
, which indi-
cates the chronology of continent inhabitation and points
to South or East Africa as the cradle of humankind
(89,90)
.
Human evolution was characterised by several large-scale
decimations, and it has been estimated that the current
world population derives from only 1000 surviving individ-
uals at a certain time point
(91)
. Such bottlenecks
(92)
, charac-
terised by strong population decrease, or where groups of
hominids were separated due to global climate changes,
volcanic winters or geographic boundaries as mountain
ridges or seas, caused gene flow and genetic drift. As a
result, different phenotypic races emerged in different geo-
graphic regions
(88,92)
. However, differences among these
populations contribute only 3 – 5 % to genetic diversity,
while within-population differences among individuals
account for 93 –95 % of genetic variation
(93)
. In other
words, genetically we belong to one species that originally
evolved in Africa and that for the great majority genetically
still resides in the Palaeolithic era. Most of the current inter-
individual genetic differences were already existent when
Homo sapiens emerged, some 200 Kya
(78)
. Bipedalism,
hairlessness, speech and the ability to store fat differentiate
humans from the closest relatives, the primates, but it is the
uniquely large brain, which allowed for symbolic con-
sciousness and pose ‘what-if’ questions, that finally made
humanity
(76)
.
Changing habitat and increasing brain size
It is assumed that during the early stages of human evol-
ution early hominins introduced more animal food into
their diets, at the expense of plant foods
(94,95)
. Subsequent
hominins further increased the amount of animal food and
consequently the energy density and (micro)nutrient con-
tent of their diet, i.e. the dietary quality. While increasing
their dietary intake from animal food, early hominins
grew taller and increased their brain mass relative to
body mass (encephalisation quotient; EQ). Brain mass in
primates relates to the number of neurons
(96)
and global
cognition
(97)
, while the human cortex also has more
cycles of cell division compared with other primates
(98)
.
During hominin evolution the first significant increase in
EQ occurred about 2 Mya (Table 1). From about 2 Mya
to 200 Kya the human ancestors tripled their brain size
from Australopithecus species with an EQ of 1·231·92 to
an EQ of 1·41–4·26 for the genus Homo
(99,100)
. The
increase in brain size and the number of neurons differen-
tiate Homo from their closest primate relatives. However, a
large brain requires an adaptation or an exaptation to
accommodate it, and notably sufficient intake of so-called
‘brain-selective nutrients’
(100,101)
to build and conserve it.
195 000 ya
African origins
125 000 ya
50 000 ya
Homo sapiens
in Europe
85 000 ya
100 000 ya
first humans
travel from
Egypt to Israel 60 000 ya
48 000 ya
33 000 ya
15 000–19 000 ya
4500 ya
25 000 ya
1500 ya
1500 ya
12 500 ya
75 000 ya
40 000 ya
22 000–25 000 ya
Humans cross
the Bering strait
65 000 ya
Humans cross
from Timor
to Australia
Fig. 2. Coasting out of Africa: following the water in the third out-of-Africa diaspora. Assumed dispersal routes of archaic and anatomically modern man out of
Africa and the supportive fossil evidence for hominin presence: (V), Australopithecus sp.; (X), Homo habilis,erectus,ergaster or antecessor;(B), H. heidelbergen-
sis;(w), H. neanderthalensis;((), H. sapiens. ya, Years ago. Source: National Geographic Society 1988, 1997; adapted from www.handprint.com/LS/ANC/
disp.html and Oppenheimer
(83)
.
Palaeolithic nutrition for disease prevention 101
Nutrition Research Reviews
Buiding a big brain
Compared with other primates, humans have an extraordi-
narily large brain
(102,103)
. To understand the expansion of
the human brain during evolution, it is important to com-
prehend its composition and its biochemistry. Brain
tissue has a unique profile of long-chain PUFA (LCP)
(99)
.
Comparison of the brain ethanolamine phosphoglycerols
of forty-two studied animal species shows an almost
identical LCP pattern, independent of the grade of ence-
phalisation, containing approximately equal proportions
of arachidonic acid (AA) and DHA. Consequently, for
normal neuronal function, mammalian brain tissue appears
to have an invariant structural requirement for both AA and
DHA. This shows that both these fatty acids are important
building blocks for building a big brain and for encephali-
sation. The weight of a newborn human brain is about
340 g
(104)
and it contains about 9 g lipid
(105)
; the brain of
a 10-month-old infant is 850 g and contains 52 g lipid.
At 3 years, the brain is 1100 g and contains 130 g lipid.
Thus, the major part of the human brain spurt occurs
postnatally
(106)
, implying that especially the newborn
infant has high demands for AA and DHA.
Toothed whales (brain weight 9000 g) and African ele-
phants (4200 g) have brains much larger than humans,
but they have lower cognitive abilities and a lower
EQ
(107)
. These observations substantiate an EQ-centred
approach to explain variation in cognition between
species. Recent analyses, however, have shown remarkable
differences between primate and non-primate brains;
a primate brain contains many more neurons than a non-
primate brain of similar size
(96,108,109)
and the absolute
number of neurons, rather than body relative to brain
ratio (EQ), best predicts cognitive ability
(97)
, although
it still needs to be determined whether humans have
the largest number of brain neurons among all mammals.
From this new neuron-centred view, there seems to
be nothing special about the human compared with the
primate brain, except for its size
(96)
, which basically
determines both the number of neurons and non-
neurons
(110,111)
. Detailed comparisons of human and
primate brains have revealed other differences, such as
different levels of gene expression
(112 – 114)
, secondary to
chromosomal rearrangements
(115)
, differences in the rela-
tive extent of the neocortical areas
(96,116)
, the distribution
of cell types
(117)
and the decrease of brain structure
volumes with increasing age in man in contrast to chim-
panzees
(118,119)
. The best predictor of cognitive ability in
humans compared with non-primates, however, still
needs to be established, but rather than EQ or brain size,
the absolute number of neurons seems a prudent candi-
date
(97,108)
, since there is no clear relationship between
neuron number and the absolute brain size among the
different animal species
(96,108,109)
.
In contrast to intuitive belief, growing a large brain and a
large skull to accommodate it is less difficult to achieve
than it seems at first glance. It was recently shown that
different levels of expression of a single gene might have
resulted in the markedly different beak shapes and lengths
of Darwin’s finches. Experimental overexpression of the
calmodulin gene in chicken embryos resulted in a signifi-
cant increase in the length of their beaks
(120,121)
. These
experiments suggest that small and seemingly insignificant
changes can have profound implications for the evolution
of anatomical size and shape and thereby provide great
potential for explaining the origins of phenotypic vari-
ation
(122)
, including increases in brain and skull size.
Analogously, many mutations in humans are associated
with either microcephaly
(123)
or macrocephaly
(124)
, while
the growth of the skull in hydrocephaly shows that
the increased skull size is secondary to the increase of its
Table 1. The development of brain weight relative to body dimensions*
Species Brain weight (g) Brain:body ratio (%) Relative EQ†
Gorilla gorilla 500 0·3 25
Pongo pygmaeus 400 0·5 32
Pan troglodytes 400 0·9 42
Australopithecus afarensis 455 1·7 41
Australopithecus africanus 450 1·0 44
Paranthropus aethiopicus 405 1·1 44
Paranthropus boisei 510 0·9 46
Paranthropus robustus 520 1·1 50
Homo rudolfensis 750 1·7 59
Homo habilis 600 1·7 57
Homo ergaster 855 –
Homo erectus 863 1·6 63
Homo heidelbergensis 1200 1·8 74
Homo neanderthalensis 1450 1·9 75
Homo sapiens (Cro-Magnon) 1490 2·4 102
Modern Homo sapiens 1360 2·3 100
EQ, encephalisation quotient.
* Adapted from Templeton
(85)
.
† Relative to modern Homo sapiens.
R. S. Kuipers et al.102
Nutrition Research Reviews
contents, suggesting that brain rather than skull size is
the limiting factor here. The evolution of certain genetic
variants associated with brain size has accelerated signifi-
cantly since the divergence from the chimpanzee some
5–6 Mya. A recent variation that occurred 37 Kya has
spread more rapidly through the human population than
could be explained by genetic drift
(125 – 128)
, suggesting
that it conferred evolutionary advantage.
The anatomical and metabolic changes encoded in the
genome (see ‘Comparative anatomy’) might have provided
hominins with the anatomical and energetic opportunity
to, over a period of several million years, steadily increase
their brain size, but these mutations per se did not fulfil
the nutrient requirements for brain expansion
(101,129 – 131)
.
The underlying small number of mutations should rather
have been accompanied, and most probably have been
preceded, by increased availability of ‘brain-specific nutri-
ents’ such as LCP for their ultimate conservation through
the process of mutation and selection, which basically
underlines both Darwin’s concept of the crucial import-
ance of ‘the conditions of existence’ and the secondary
role of mutation. An example may come from current
knowledge on the sources of AA and DHA. In humans,
both AA and DHA can be synthesised from their precursor
essential fatty acids a-linolenic acid (ALA) and linoleic acid
(LA) (Fig. 3), respectively. ALA and LA are present in
various natural food resources. ALA is predominantly
found in plant foods, while LA is mainly found in vegetable
oils such as sunflower-seed oil. Both AA and DHA may
derive from their synthesis from abundantly consumed
precursor fatty acids ALA and LA, but in humans and
especially neonates, these synthetic activities are insuffi-
cient to cope with metabolic demands
(132)
. Consequently
both these LCP, but especially those of the n-3 series,
need to be present in sufficient quantities in our diet. It is
still under debate what dietary resource(s) provided the
LCP that enabled us to grow a large brain
(101,133 – 137)
.
The probability of hunting on the savanna
It has been a longstanding paradigm in palaeoantho-
pology that early human evolution occurred in a dry and
open savanna environment
(138 – 140)
. Recent studies from
the Afar basin
(68,141)
, although recently contested
(142 – 144)
,
indicated that the habitat of Ardipithecus ramidus at
about 4·4 Mya was characterised not by savanna but by
woodland to grassy woodland conditions. Human charac-
teristics, such as poor water-drinking capacity, excessive
urination and transpiration and poor water retention sup-
port the argument that we would be poorly adapted
savanna dwellers
(140)
.
A second long-reigning paradigm was ‘man the hunter’,
which was the standard version of human origins advo-
cated for many years. Washburn & Lancaster
(94)
referred
at most to our most recent antecessors, Homo sapiens
and possibly H. neanderthalensis, when they claimed
that our intellect, interests, emotions and basic social
life are evolutionary products of the hunting adaptation.
The strongest argument against this hunting paradigm
comes from combined studies of past and present-day
hunter–gatherer societies indicating that the role of hunt-
ing is exaggerated, notably (around the campfire) in
hunter–gatherer societies, since the majority of the dietary
protein is in reality obtained by women gathering nuts,
tubers and small animals
(145 – 147)
. Cordain et al.
(148)
showed that only 2535 % of energy (en%) of subsistence
in worldwide huntergatherer communities is derived
from hunting, while the remainder is derived from both
plant and fished food. Thus, while meat from large game
may have been the most valued food, it is highly unlikely
that it was the most valuable (nutritionally important) food
resource from a dietary perspective
(41,149)
. At present, the
niche of early hominins and thus the environment of
human evolution, and, most importantly for the present
review, the nutritional composition of the early human
diet are still heavily debated
(150)
.
Reconstruction of our ancient diet
In the next sections we will discuss various views on
(changes in) the hominin ecological niche that over time
shaped the human genome to what it currently is.
Palaeo-environments
Sahelanthropus, Orrorin and Ardipithecus. In the late
Miocene (up to 5·3 Mya), the African continent became
9
9
6
6
5
CE
Diet Diet Diet or lipogenesis
CE
CE
CE
CS
22 : 6
n-
3
24 : 6
n-
3
24 : 5
n-
3
22 : 5
n-
3
20 : 5
n-
3
20 : 4
n-
3
18 : 4
n-
3
18 : 3
n-
318 : 2
n-
618 : 1
n-
7
20 : 1
n-
720 : 0
18 : 0
16 : 0
22 : 0
24 : 0
18 : 3
n-
6
20 : 3
n-
6
20 : 4
n-
6
22 : 4
n-
622 : 3
n-
9
20 : 3
n-
9
20 : 2
n-
920 : 1
n-
9
22 : 1
n-
9
24 : 1
n-
9
18 : 2
n-
9
16 : 1
n-
7
n-
3
and n-
6
series n-
7
and n-
9
series
16 : 1
n-
9
18 : 1
n-
9
24 : 4
n-
6
24 : 5
n-
6
22 : 5
n-
6
Fig. 3. Metabolism of the parent essential fatty acids and endogenously
synthesised fatty acids. D9, D9-Desaturase; CE, chain elongation; D6,
D6-desaturase; D5, D5-desaturase; CS, chain shortening through peroxiso-
mal b-oxidation. 18 : 3n-3, a-linolenic acid; 18 : 2n-6, linoleic acid; 18 : 1n-9,
oleic acid; 20 : 5n-3, EPA; 20 : 4n-6, arachidonic acid; 20 : 3n-9, mead acid;
22 : 6n-3, DHA.
Palaeolithic nutrition for disease prevention 103
Nutrition Research Reviews
more arid, which resulted in fragmentation of the (sub)tro-
pical forests and the appearance of more open environ-
ments
(151)
. The widespread dispersal of some of the
earliest hominins such as Sahelanthropus
(65,152)
, and Aus-
tralopithecus bahrelghazali from Chad, might be explained
by the presence of the relatively low-lying humid East
West corridor constituted by the remnants of the Cretac-
eous Central African and Sudan Rifts between Western
and Eastern Africa
(153,154)
. The reconstructed environment
of Sahelanthropus (about 7 Mya) suggests a mosaic of
gallery forest at the edge of a deep, well-oxygenated lake,
swampy and vegetated areas, and extensive grasslands
(155)
.
Since there is no indication of carnivore modification or
fluvial transport of its bones, Sahelanthropus chadensis
probably lived in this area
(156)
. The palaeo-environment
of Orrorin (about 6 Mya) was probably characterised by
open woodland, with dense stands of trees in the vicinity
and possibly fringing the lake margin and/or streams
that drained into the lake
(157)
.Ardipithecus kadabba
(5·6 Mya) remains are associated with wet and closed,
grassy woodland and forest habitats around lake or river
margins
(158)
.Ardipithicus ramidus (4·4 Mya) lived in or
near a groundwater-supported grassy woodland to
forest
(159)
. Additionally, the abundance of fossilised shal-
low-water aquatic species such as catfish, barbus, cichlidae
and crocodiles additionally suggests an episodically present
flood-plain environment
(159)
.
Early Australopithecus species.Australopithecus ana-
mensis appeared at about 4·2 Mya and its environment
was characterised by a mix of wetlands and terrestrial
environments, such as lacustrine and fluvial floodplains,
woodland and gallery forest
(156,160 – 163)
. The later Australo-
pithecus afarensis survived in a variety of habitats
(164)
, but
apparently thrived better in the more wooded and humid
conditions in the Afar basin than in the relatively dry Lae-
toli area
(165)
. Stewart
(156)
pointed out that in Africa the only
environmental constant in hominin sites throughout the
period from 3·4 to 2·9 Mya was a wetlands habitat, charac-
terised by aquatic herbaceous vegetations around lakes
and rivers, with large populations of wetland fauna such
as reduncines and hippopotami. Hence, these wetlands
could have been refuge for early hominins throughout an
extensive period of human evolution.
Paranthropus, late Australopithecus and Homo species.
About 2·9–2·5 Mya tectonic and global climatic changes
made Africa cooler and drier
(166 – 169)
. The great wet forests
of middle Africa retreated and made place for more
savanna grasslands. It is around this time, from about 2·6
Mya onwards, that the first traces of the new hominin
genus Homo appeared in the archaeological record
(140)
.It
has been suggested that alternating wet and dry periods
after 2·7 Mya could have isolated hominin populations
around sources of potable water, while forcing them to
the extremes of their conditions of existence
(156)
and thus
facilitating specialisation
(170)
, either by adaptation or exap-
tation. Compared with Australopithecus,Paranthropus
existed in slightly more open habitats, including wetlands
and grasslands, but also in woodland and bushland
areas. The habitats of Homo species seem similar to
those utilised by Paranthropus species
(161)
, but Homo
remains at Olduvai Gorge and Koobi Fora are associated
with well-vegetated swamps, lakes and river margins,
and (semi-) aquatic fauna
(171,172)
. Only the later Homo
species are also found in assemblages that indicate extre-
mely arid and open landscapes such as savanna
(161)
.
Also, it has been suggested that hominins and other
(aquatic) species dispersed throughout Africa along water
systems, while even the last out-of-Africa migration might
have occurred via the ‘green Sahara’ that existed during
the last interglacial (125 Kya)
(156,173)
.
In conclusion, the palaeo-environmental evidence
suggests that early hominins lived in the proximity of
water. However, it is frequently argued that bones are pre-
ferentially preserved in lake, river or fluvial sediments,
making their recovery in any other than an aquatic setting
unlikely
(174)
. Alternatively, hominin remains may have
been relocated to the water by carnivores
(162)
, including
crocodiles. Nevertheless, the combined evidence strongly
suggests that early hominins frequented the landwater
ecosystem and thus lived there. Joordens et al.
(154)
pro-
posed, based on comparison with other terrestrial omni-
vores, that the default assumption should be that
hominins living in freshwater or marine coastal ecosystems
with catchable aquatic resources could have consumed
these aquatic resources
(154,175)
.
Comparative anatomy
The diet of our closest relatives. Field studies on our clo-
sest relatives, the extant apes, show that their preferred
food items are primarily fruits and/or leaves and stems
from terrestrial forests. Lowland gorillas, for example,
derive 57 % of their metabolisable energy (en%) from
SCFA derived from colonic fermentation of fibre, 2·5 en%
from fat, 24 en% from protein and 16 en% from carbo-
hydrate
(176)
. ‘Fallback foods’ are consumed when preferred
foods are unavailable
(177)
and are generally composed of
herbaceous plants and high-fibre fruits from aquatic and
terrestrial environments
(156)
. Like our closest rela-
tives
(156,178 – 181)
, hominins might have used foods from
the aquatic environment as fallback foods, while, although
speculative, this niche might eventually have proven
favourable with regard to subsequent encephalisation.
Teeth morphology and dental microwear. Comparative
anatomy (Fig. 4) of the hominins might confer some infor-
mation about these fallback and preferred foods of our
ancestors. Dental studies of Sahelanthropus (Fig. 1) describe
that the teeth had thick enamel
(65)
, similar to orangutans,
suggesting that it could eat hard and tough foods
(182)
, such
as available from the lakeshore vegetation
(156)
.Ardipithecus
ramidus, however, had thin molar enamel and smaller teeth
compared with later hominins. This dental morphology is
R. S. Kuipers et al.104
Nutrition Research Reviews
consistent with a partially terrestrial, omnivorous/frugivor-
ous niche
(183)
. Studies on cranio-dental changes such as
tooth size, tooth shape, enamel structure and jaw biomecha-
nics indicate that Australopithecus and Paranthropus had
prominent jaws, relatively flat molar teeth, small incisors
and thick enamel, suitable for breaking and crushing small
hard, brittle foods such as fruits, nuts and underground
storage organs
(150)
, but unsuitable for breaking down
tough plant foods or tearing meat. Together, this would
allow early hominins to eat both hard and soft, abrasive
and non-abrasive foods, which suits well for life in a variety
of habitats
(184)
.
In addition to studies on teeth morphology, microwear
studies are essential. Dental microwear studies analyse
tooth-wear, showing evidence for where teeth were actu-
ally used for and thus what an animal in reality ate
(185)
.
While adaptive morphology will give important clues
about what a species was capable of eating, microwear
studies reflect what an animal ate during some point in
its lifetime. In these studies, ‘complexity’ is used as an indi-
cator for hard and brittle items, while ‘anisotrophy’ is an
indicator for tough foods
(186)
.
Most primates show either low complexity combined
with high anisotrophy, indicative of consumption of
tough foods such as leaves, stems and meat, or high com-
plexity with low anisotrophy associated with hard-brittle
foods, such as nuts and seeds
(150,187)
.Ardipithecus rami-
dus’s preference for an omnivorous/frugivorous diet was
confirmed by microwear studies
(183)
, suggesting a diet of
fleshy fruits and soft young leaves
(150)
. Conversely, micro-
wear textures of Australopithicus afarensis and anamensis
show striations rather than pits (low complexity and low
anisotrophy), i.e. patterns similar to those of grass-eating
and folivorous monkeys instead of the predicted diets pre-
dominated by hard and brittle foods
(187,188)
.Australopithe-
cus africanus showed microwear patterns that were more
anisotropic, suggestive for consumption of tough leaves,
grasses and stems
(189)
.Paranthropus robustus, also know
as the ‘Nutcracker Man’, has enormous, flat, thickly enam-
elled teeth that are combined with a robust cranium, mand-
ible and powerful chewing muscles, suggestive of breaking
hard and brittle foods
(186)
. After microwear analysis of its
teeth, however, Ungar et al.
(150,186)
showed that P. robustus
had low complexity and anisotrophy; thus Paranthropus
might only have consumed mechanically challenging
items as fallback foods when preferred foods were un-
available. Similarly, microwear studies support the notion
that the diet of P. boisei contained large quantities of
low-quality vegetation, rather than hard objects
(190)
.
Generally, microwear studies confirm earlier dental
topography studies
(191)
, which revealed the incorporation
of more fracture-resistant foods, i.e. tougher foods as
leaves, woody plants, underground storage organs and
animal tissues, in the diet of Australopithecus africanus
compared with Australopithecus afarensis and for
P. robustus compared with Australopithecus africanus
(187)
.
Dental topographic analysis suggested that successive
Homo species emphasised more on tougher and elastic
foods, perhaps including meat
(191)
. The latter suggestion
is in line with the optimal foraging theory, which states
that humans prefer foods with high energy density over
those with low energy density
(192,193)
.
Microwear studies confirmed that early Homo, such as
H. erectus and H. habilis, did not prefer fracture-resistant
foods, although some H. erectus specimens showed more
small pits than H. habilis members, suggesting that none
of the early Homo specialised on very hard-brittle or
tough foods, but rather could consume a varied diet
(194)
.
This does not imply that early Homo had very broad
diets, but rather that early Homo was adapted to subsist
in a range of different environments, providing evolution-
ary advantage in the climatic fluctuations and the mosaic of
habitats in Africa during the late Pliocene
(195)
. A study on
dental microwear of 300 000-year-old H. heidelbergensis
teeth from Sima de los Huesos in Spain showed striation
patterns that indicated a highly abrasive diet, with substan-
tial dependence on poorly processed plant foods such as
roots, stems and seeds
(196)
. Lalueza et al.
(197)
compared
teeth of very recent huntergatherers (Inuit, Fueguians,
Bushmen, Aborigines, Andamanese, Indians, Veddahs,
Tasmanians, Laps and Hindus) with Middle and Upper
Pleistocene fossils. Their results indicate that some
Diastema Canine Premolars
Molars
Incisors
Pan Australopithecus Homo
Fig. 4. Lower jaw of a chimpanzee (Pan troglodytes), Australopithecus africanus and Homo sapiens. Note the somewhat human-like shape of the teeth, but ape-
like axis in the jaw of Australopithecus.qAustralian Museum.
Palaeolithic nutrition for disease prevention 105
Nutrition Research Reviews
Neanderthals resemble carnivorous groups, while archaic
H. sapiens show a more abrasive diet, partly dependent on
vegetable materials.
Overall, remarkably few studies have related microwear
patterns to hominin diet for the period between 1·5 Mya
and 50 Kya (PS Ungar, personal communication). Studies
in more recent hominins, such as from an Upper Palaeo-
lithic site in the Levant (22 500 23 500 before present;
BP) showed a high frequency of long narrow scratches
and few small pits, suggesting a tough abrasive diet of
aquatic foods rather than a diet with hard foods that
needed compressive force
(198,199)
. A study of subsequent
local hunter–gatherer (12 500–10 250 BP) and farmers
(10 250 –7500 BP) living in the Levant showed larger
dental pits and wider scratches among the farmers com-
pared with the huntergatherers, suggesting that the
implementation of agriculture led to a more fracture-
resistant diet
(199)
.
Gut morphology, energy expenditure and muscularity.
Gut morphology studies
(200,201)
support the introduction
of animal foods, at the expense of vegetable foods, in
the diet of early Homo. The dominance of the colon
(.45 %) in apes indicates adaptation to a diet rich in
bulky plant material, such as plant fibre and woody
seeds. In contrast, the proportion of the human gut domi-
nated by the small intestine (.56 %) suggests adaptation to
a diet that is highly digestible, indicating a closer structural
analogy with carnivores than to folivorous or frugivorous
mammals. Importantly, the shorter gut in Homo, as com-
pared with primates, might have had some other advan-
tage. During the evolution from Ardipithecus and
Australopithecines to early Homo, the improvement of diet-
ary quality coincided with an increase in height, the size of
our brain and its metabolic activity. However, an increase
in body size coincides with increased daily energy
demands, notably during gestation
(202)
and lactation
(203)
.
It was, for example, calculated that daily energy expendi-
ture for a Homo erectus female is about 66 % higher com-
pared with an Australopithicine female, while being
almost 100 % higher in a lactating Homo erectus female
compared with a non-lactating, non-pregnant Australo-
pithicine
(204)
. These high energy demands might have
been met by increased female fat reserves
(205,206)
, such as
demonstrated by the presence of female steatopygia in
some traditional human populations, such as the Khoisan
of southern Africa.
Apart from the extra energy need for reproduction and
increasing height, the human brain of a modern adult uses
20–25 en% of the total RMR, while this value is 8 9 en%
for a primate
(207)
. It has been postulated that the extra
energy needs did not derive from a general increase in
RMR, but partly from a concomitant reduction of the gastro-
intestinal tract
(208)
and a reduction in muscularity
(207)
. These
features are combined in the ‘expensive tissue hypothesis’ of
Aiello & Wheeler
(208)
that points at the observation that the
mass of the human gastrointestinal tract is only 60 % of that
expected for a similar-sized primate and that humans are
relatively under-muscled compared with other primates
(207)
.
Interestingly, the negative relationship between gut and
brain size across anthropoid primates
(209)
was confirmed
in a study with highly encephalised fish
(210)
, whereas it
became falsified in mammals
(102)
. Unfortunately, however,
the latter study did not include marine mammals
(102)
, while
it is questionable whether with respect to brain development
humans adhere to general mammalian rules
(103)
. Other
adaptations might have saved energy expenditure as well.
The short human inter-birth interval
(204)
, compared with
inter-birth intervals of 4–8 years in the gorilla, chimpanzee
and orangutang
(211)
, reduces the most expensive part of
reproduction, i.e. lactation
(212,213)
, while the shift from quad-
rupedal to bipedal locomotion also reduced daily energy
expenditure
(214)
. Together, all of these adaptations allow
for an increased daily energy expenditure, including the
reallocation of energy to the metabolically active brain, but
were only possible after Homo included more energy-
dense foods into its diet. Brain mass in primates is positively
related to dietary quality and inversely to body weight
(207)
.
Generally, a shift towards more energy-dense foods includes
a shift from primarily carbohydrate-rich vegetables to fat-
and protein-rich animal foods. However, it has also been
suggested that a shift from the complex carbohydrates in
leafy vegetables towards underground storage organs,
such as tubers, might have provided easy-to-digest carbo-
hydrates
(200,215)
to support a larger hominin body mass.
A phenotypic specialisation on non-preferred resources,
without compromising the ability to use preferred
resources, is also known as Liem’s paradox
(216)
. This para-
dox is important to keep in mind during attempts to recon-
struct the preferred diet from the available evidence.
Interestingly, Stewart
(156)
recently noted that in the case
of Paranthropus’s phenotype with regard to its fallback
food, there is just as much evidence to talk about a ‘Nut-
cracker Man’ as there is to talk about a ‘Shellcracker
Man’. Thus, a phenotypic characterisation needs support
from other studies to confirm adaptation to preferred
rather than fallback foods. In other words, it should be
noted that not all physical characteristics might be taken
as unambiguous proof for the preferred diet of early homi-
nins (Liem’s paradox). The increasing absolute body size
and brain size and the reduction in gut size, however, do
indicate a shift from low- to high-dietary-quality foods for
more recent hominins.
Biogeochemistry
Evidence from the strontium:calcium ratio. Based upon
the principle ‘you are what you eat’
(217)
several techniques
have been developed to study early hominin diets
(218)
.
Trace element studies first started with Sr:Ca ratios, which
decrease as an animal moves up the food chain, secondary
to the biological discrimination against strontium
(219)
. A first
study
(220)
suggested that Paranthropus robustus (Fig. 1)
R. S. Kuipers et al.106
Nutrition Research Reviews
had lower Sr:Ca ratios compared with contemporaneous
Papio (baboon) and Procavia (hyrax), suggesting that
Paranthropus was not an exclusive herbivore. However,
a subsequent study showed that two Homo specimens
had a higher Sr:Ca ratio than Paranthropus
(221)
. Since
Homo had been assumed to consume more animal foods
than Paranthropus and thus have a lower Sr:Ca ratio,
these higher Sr:Ca ratios needed explanation. For example,
consumption of specific foods with a high Sr:Ca ratio
might have increased the ratio in Homo compared with
Paranthropus. Foods in the area of research with elevated
Sr:Ca ratios were mainly geophytes. These are notably
perennial plants with underground food storage organs,
such as roots, bulbs, tubers, corms and rhizomes. Conse-
quently, this discrepancy has been attributed to the
consumption of underground storage organs by early
Homo
(215,221)
. The use of these underground storage
organs may have become necessary from the start of a
first period of aridity about 2·8 Mya, when forest was
replaced by drier woodlands, forcing hominins to search
for available resources around water margins
(222)
.
Although promising at first, the use of Sr:Ca ratios was
found to suffer from several limitations. For example, a
problem is that hominin Sr:Ca ratios in fossilised bones
alter with time
(223)
, a process that is known as diagenesis.
This problem can be circumvented by the use of tooth
enamel, which is less susceptible to diagenesis than
bone
(223)
. Subsequent studies showed that Australopithe-
cus africanus had a higher Sr:Ca ratio in its enamel
compared with Paranthropus and contemporaneous
browsers, grazers, baboons and carnivores
(224 – 226)
. The
interpretation of these findings, however, remains a subject
of debate. For example, a group of brown seaweeds and
some aquatic plants discriminate against Ca, resulting in
an increase in the Sr:Ca ratio, and likewise in the Sr:Ca
ratio of the fish feeding on them
(226,227)
. Similarly, leaves
from trees have lower Sr:Ca ratios compared with grasses,
which becomes subsequently reflected in the Sr:Ca ratios
of browsers and grazers, respectively
(228)
. Thus, it might
be argued that the relatively high Sr:Ca ratios in Australo-
pithicines and Homo reflect their consumption of aquatic
resources or of animals such as insects or other small
animals feeding on grasses. For now, the exploration of
especially Sr:Ca ratios as a dietary proxy method has
largely been stalled
(229)
.
Evidence from the barium:calcium ratio. Another trace
element ratio that might provide information on the
composition of the early hominin diet is the Ba:Ca ratio,
particularly when used in a multiple-element analysis
with Sr:Ca and Sr:Ba ratios
(224,230)
. Combined Ba:Ca and
Sr:Ba ratios clearly differentiate grazers from browsers
and carnivores in both modern and fossil mammals
(230)
.
Hominins have a lower Ba:Ca and higher Sr:Ba ratio
compared with grazers and browsers. Paranthropus
shows considerable similarity for both ratios with both car-
nivores and Papionins (baboons), while Australopithecus
shows an even higher Sr:Ba ratio. The unusual combi-
nation of a high Sr:Ca and low Ba:Ca ratio in hominins
(and baboons) has been further observed for some animals
such as warthogs and mole rats that make extensive use of
underground resources
(231)
. Finally, the high Sr:Ba ratio,
as observed in Australopithecus, might derive from the
consumption of grass seeds, which have Sr:Ba ratios
three to four times higher than grass straw, while consump-
tion of these grasses is also consistent with stable-isotope
evidence (see below) showing that Australopithecus
derived a substantial part of its diet from C
4
resources.
Although not included in any study so far, Sr:Ba ratios
in aquatic foods might add to the understanding of the
unusual combination of low Ba:Ca and high Sr:Ba ratios.
Evidence from the
13
C:
12
C ratio. Fractionation studies
of carbon isotopes differentiate between different routes
of photosynthesis. While most tropical African woody
plants from forests (like fruits, leaves, trees, roots,
bushes, shrubs and forbs) use the C
3
photosynthetic path-
way, some South African
(232)
and East African
(233)
grasses
and sedges use the C
4
photosynthetic pathway. C
4
plants
such as sedges (for example, Cyperus papyrus) typically
occur in a mosaic of extensive seasonal and perennial shal-
low freshwater wetlands that can also be found in savanna
and ‘bushvelds’ receiving summer rainfall
(234)
. The real
impact of C
4
plants occurred with their spread into Eastern
and Southern Africa during the Pliocene
(235)
. Tissues of
plants that utilise the C
4
pathway have a relatively high
content of the stable carbon isotope
13
C (about 1·1 % of
carbon), since C
3
plants discriminate more strongly against
13
CO
2
during photosynthesis. As a result C
3
and C
4
plants
have quite different
13
C:
12
C ratios in their tissues, as have
the herbivorous animals that feed on these plants
(228,232)
and the carnivores that prey on these herbivores
(193,206)
.
Differences are expressed as d
13
C values (d
13
C¼
((
13
C:
12
C)
sample
2(
13
C:
12
C)
standard
)£1000/(
13
C:
12
C)
standard
)
in parts per thousand (‰) relative to the
13
C:
12
C ratio in
the reference standard (named Pee Dee Belemnite; PDB),
i.e. the carbonate obtained from the fossil of a marine
Cretaceous cephalopod (Belemnitella americana) which
is highly enriched in
13
C(
13
C:
12
C ratio ¼0·0112372). Con-
sequently, most animals have negative d
13
C values (Fig. 5).
The d
13
C ranges from 235 to 221 ‰ (mean 226 ‰) in C
3
plants and from 214 to 210 ‰ (mean 212 ‰) in C
4
plants
(225)
. Studies that attempted to reconstruct mamma-
lian food webs indicated that carbon is slightly enriched
(1 –2 ‰) with each trophic step
(193,206)
. To facilitate com-
parison of current and historical animals, d
13
C analyses
are predominantly performed in hard tissues, such as
bone collagen and enamel (notably apatite), since these
constitute the majority of the fossil record. It was shown
that enamel mineral is enriched by about 13 ‰ compared
with dietary d
13
C
(238)
, while collagen is enriched by
about 5 ‰ compared with dietary d
13
C
(225)
. Collagen
from terrestrial mammal C
3
herbivores shows a value
of 221 ‰ (range 222 to 214 ‰), while in collagen of
Palaeolithic nutrition for disease prevention 107
Nutrition Research Reviews
C
4
herbivores this value is 27‰ (212 to 26 ‰). Their
respective carnivores show collagen values of 219 ‰
(221 to 214 ‰) and 25‰ (28to22 ‰), respect-
ively
(225)
. Marine phytoplankton, which uses the C
3
path-
way, shows an average value of 222 ‰
(239)
. Collagen of
marine fish shows a range from 215 ‰ to 210 ‰, while
the values in collagen of reef fish range from 28to
24‰
(240)
. Marine carnivores have, similar to terrestrial
carnivores, intermediate values of 214 ‰, ranging from
210 ‰ in collagen of sea otters to 215 ‰ in collagen of
the common dolphin
(239,240)
. Thus, also the d
13
C values
of marine carnivores compare well with those of their
prey. Finally, d
13
C values for the muscle of freshwater
fish species range from 224 to 213 ‰, but considerable
variation may exist between different lakes
(241)
. Unfortu-
nately, no d
13
C data are available for terrestrial piscivorous
carnivores, but the consistency of the other data suggests
that these might be between 224 and 213 ‰, i.e. compar-
able with their prey (Fig. 5).
Consistent with the data above, Schoeninger et al.
(242)
showed that European agriculturalists consuming C
3
grasses had much lower d
13
C values in bone collagen
(221 to 219 ‰) compared with Mesoamerican agricultur-
alist consuming C
4
maize (27to25 ‰), while North
American and European fishergatherers had intermediate
values (215 to 211 ‰). However, bone collagen proved
less reliable to study early hominin diets. For that purpose
the
13
C:
12
C ratio is preferably measured in tooth enamel.
To compare collagen d
13
C values with enamel d
13
C
values, an additional (8 ‰) correction has to be made.
Similar to the clear distinctions between bone collagen of
modern grazers, browsers and their carnivores, tooth
enamel data from fossilised fauna from South Africa
showed similar differences for Plio-Pleistocene C
3
feeders
(211·5 ‰) and C
4
feeders (20·5 ‰), with Australopithe-
cus,Paranthropus and Homo taking intermediate positions
(210 to 24‰)
(231,234,237,243)
, which compared well with
the values for contemporaneous felids (210 to
20·5 ‰)
(231,237,244)
(Fig. 5). These results clearly demon-
strated that a significant proportion of the diets of the
early hominins from Swartkrans, Makapansgat and Sterk-
fontein derived from C
4
resources. Using these data it
Freshwater fish
C4 agriculturalist*
Reef fish*
C4 carnivore*
C4 herbivore*
Sea grasses
–35 –25 –15 –5
Marine fish*
C4 plants
Fisher–gatherer*
Marine carnivore*
Crustacean*
Marine mammal hunter*
C3 herbivore*
Freshwater carnivore§
C3 agriculturist*
C3 carnivore*
Marine plankton‡
C3 plants
Baboon sp.†
Termites
Paranthropus
sp.†
Australopithecus
sp.†
Homo
sp.†
Normalised d 13C values (%)
Fig. 5. Normalised collagen d
13
C values (mean and range; in per thousand (‰)) in plankton, crustaceans, sea grasses, C
3
and C
4
plants; of marine crustaceans,
fish and freshwater fish and their respective carnivores; of terrestrial C
3
and C
4
herbivores and their carnivores; and of human groups in historic and prehistoric
times. * Corrected
(229)
for collagen (25 ‰). Corrected
(238)
for enamel (213 ‰). Arbitrary range of ^1 ‰ due to a lack of data. § As predicted from other
predator– prey relationships and after correction
(239)
for tropic level (þ1 ‰). Adapted from Ambrose & Deniro
(228)
, Sponheimer et al.
(231,247)
, Peters & Vogel
(234)
,
Lee-Thorp et al.
(237,244)
, Kelly
(239)
, Schoeninger & Deniro
(240)
, Mbabazi et al.
(241)
, Schoeninger et al.
(242,246)
, Sponheimer & Lee-Thorp
(243,248,249)
and van der
Merwe et al.
(245)
.
R. S. Kuipers et al.108
Nutrition Research Reviews
was calculated that South African Paranthropus derived
14 –47 % of its diet from C
4
sources, compared with
5–64 % in Australopithecus and 20–35 % in Homo
(245)
.
A second study in Olduvai showed that the Tanzanian
Paranthropus boisei derived 77 – 81 % and Homo 23 –49 %
from its diet from C
4
resources
(245)
. The low nutritional
value of grasses, and microwear studies (see above)
render it unlikely that humans were directly eating
grass
(231,243)
. Analogously, the sizeable carnivory of C
4
-
consuming mammals (such as cane rats, hyraxes or juven-
ile bovis) was argued to be practically impossible and thus
unable to leave a strong C
4
signature
(243)
. However, at
about 1·8 Mya, there were extensive wetlands in the Oldu-
vai area, where a river from the Ngorongoro mountains
entered the area, while at 1·5 Mya the Peninj river pro-
duced wetlands near Lake Natron
(156)
. Some researchers
investigated the edible plants in a present-day wetland
(Okavango Delta) and found that the rhizomes and
culms of three species of C
4
sedges were edible, the
most common one of which is Cyperus papyrus
(245)
. How-
ever, it seems unlikely that the C
4
signature in all early
hominins derived from the consumption of papyrus. It
was recently suggested that P. robustus and especially
P. boisei had a diet of primarily C
4
resources, most probably
grasses or sedges, from savanna or wetland environments,
respectively
(190)
. Theoretically, a good source of C
4
foods would be a seasonal freshwater wetland with flood-
plains and perennial marshlands, with an abundance of
easy accessible aquatic foods, large aggregations of nesting
birds and calving ungulates
(234)
. Consumption of termites
could have contributed to the high C
4
signature observed
in hominin fossils (Fig. 5), but it seems unlikely that termites
could explain values as high as 50 % of the diet from C
4
( 243)
.
Finally, an enamel C
4
signature of 210 to 24 ‰ in hominins,
which translates into a soft tissue signature of 223 to 217 ‰
and a collagen signature of 218 to 212 ‰ (see above),
might also derive from the consumption of small
freshwater aquatic animals or fish, since they compare well
with the d
13
C values of 224 to 213 ‰ for freshwater
fish
(241)
and 218 to 29 ‰ in collagen of crustaceans and
anthropods
(240)
, respectively. Moreover, d
13
C values for
hominins are similar to those reported for marine mammal
hunters, freshwater fish, crustaceans, fishergatherers,
marine and freshwater carnivores and marine fish (Fig. 5).
In agreement with the variability selection hypothesis
of Potts
(170)
, which states that large disparities in
environmental conditions were responsible for important
episodes of adaptive evolution, the wide range in d
13
C
values in particularly Australopithecus suggests that early
hominins utilised a wide range of dietary sources, includ-
ing C
4
resources. This contrasts with chimpanzees,
which, even in the most arid and open areas of their
range, are known to consume negligible amounts of C
4
resources, despite their local abundancy. Consequently,
chimpanzees show very little variability in their d
13
C
carbon signature
(246,247)
. This underscores that even if
contemporaneous chimpanzees and early hominins
inhabited similar habitats, hominins had broadened their
dietary range sufficiently to survive in habitats uninhabita-
ble by chimpanzees. The latter assumption provides an
interesting perspective on the recent data, which suggest
that C
4
foods were absent in the diet of Ardipithecus
ramidus at 4·4 Mya. Consequently, it has been proposed
that the origins of the introduction of C
4
foods into the
hominin diet lie in the period between 3 and 4 Mya
(229)
.
Limited evidence from the
15
N:
14
N ratio. Another
stable-isotope ratio that has received considerable attention
is the N isotope (
15
N:
14
N) ratio. A number of food web
studies have shown that each step in the food chain is
accompanied by 3–4 ‰ enrichment in d
15
N
(228,239)
and
that d
15
N can therefore be useful as a trophic level indi-
cator. Additionally, animals feeding in marine ecosystems
have higher values compared with animals feeding on ter-
restrial resources
(242)
. For example, North American and
European fishergatherers and North American marine
mammal hunters and salmon fishers had much higher
d
15
N values (þ13 to þ20 ‰) compared with agricultural-
ists (þ6toþ12 ‰). Analyses of phyto- and zooplankton
suggest that freshwater organisms have d
15
N values inter-
mediate to terrestrial and marine organisms
(242)
.d
15
N
values are routinely measured in bone collagen, but it
has been shown that good-quality collagen (preserving
the original d
15
N value) can, and only under favourable
conditions, survive up to a maximum of 200 000
years
(225)
. This limits d
15
N isotopic studies to Late Pleisto-
cene hominins (see below), but with improved technology,
future studies using collagen extracted from tooth enamel
may expand their application to early hominins
(238)
.
Limited evidence from the
18
O:
16
O ratio. A final iso-
tope that might provide information about an animal’s
diet and thermophysiological adaptations is the oxygen
isotope ratio (
18
O:
16
O). More energy is needed to vaporise
H
2
18
O than H
2
16
O. When ocean water evaporates and during
evapotranspiration, i.e. the sum of evaporation and plant
transpiration from the earth’s land surface to the atmos-
phere, more of the lighter isotope evaporates as
H
2
16
O. The ensuing
18
O enrichment of transpiring leaves
results in
18
O enrichment in typical browsers such as
kudu and giraffe who rely less on free drinking water
and derive most of their water from the consumption of
the
18
O-enriched plant water. As the
16
O-enriched water
vapour in clouds moves inland, some of it condenses as
rain, during which more of the heavier isotope (as H
2
18
O)
rains out, making the d
18
O of coastal rain only slightly
less enriched than the original vaporated ocean water,
while the d
18
O of the remaining water vapour that even-
tually comes down is highly negative (i.e. more
18
O
depleted). Consequently, river water from rain and melting
ice is more d
18
O negative than seawater. Roots derive their
water from meteoric or underground water that is thus
relatively depleted from
18
O and so become animals that
are consuming these roots
(248,249)
. Browsers of leaves
Palaeolithic nutrition for disease prevention 109
Nutrition Research Reviews
undergoing evapotranspiration and consumers of roots
may thus be expected to have high and low d
18
O values,
respectively.
Australopiths showed lower d
18
O values compared with
Paranthropus, but the meaning of this difference remains
uncertain. However, one might argue that Australopithecus
preferred less arid conditions compared with Paranthropus
or was more dependent on seasonal drinking water
(231)
.
Low d
18
O was additionally found in primates and suids,
which might be linked to frugivory, although this is not
supported by the higher
18
O values found in Ardipithecus
ramidus compared with Australopithicines
(68,229)
. Taken
together, the use of d
18
O for exploration of ancient
human diets is still in its infancy, but might, especially in
combination with other isotope ratios, become more
appreciated in the future.
Isotopic data for more recent hominins. It would be of
high interest to explore the hominin diet during the last
spurt of encephalisation between 1·9 Mya to 100 Kya,
when brain size tripled in size to volumes between 1200
and 1490 cm
3
for Homo erectus,H. heidelbergensis,
H. neanderthalensis and modern H. sapiens
(100)
. Isotopic
data for this period are, however, absent. Due to the lim-
ited preservation of collagen beyond 200 000 years, and
the near absence of C
4
plants in Europe, these answers
will have to come from further studies with tooth enamel
in Africa and Asia. So far, there is no isotope evidence
for the diet of Homo between 1·5 Mya up to 50 Kya
(MP Richards, personal communication).
Dietary information from more recent humans comes
from data on d
13
C, supplemented with data on d
15
N and
the
13
C:
15
N ratio. The
15
N-isotope values of bone col-
lagen
(242)
for differentiation between aquatic and agricul-
tural diets were additionally verified by the study of the
sulfur isotope ratios (
34
S:
32
S), since high intakes of
marine organisms also result in higher d
34
S values
(250)
.
Combined isotope studies reveal high intakes of animal
protein, with substantial proportions derived from fresh-
water fish by Upper and Middle Palaeolithic (4012 Kya)
humans in Eurasia, indicating that in some populations
about 30 % of dietary protein came from marine
sources
(250 – 256)
. In contrast, isotopic evidence indicates
that Neanderthals were top-level carnivores that obtained
most of their dietary protein from large terrestrial herbi-
vores, although even Neanderthals certainly exploited
shellfish such as clams, oysters, mussels and fish on
occasion
(250 – 252)
. At the onset of the Neolithic period
(5200 years ago), there was a rapid and complete change
from aquatic- to terrestrial-derived proteins among both
coastal and inland Britons compared with Mesolithic
(9000–5200 years ago) British humans
(254)
, which
coincides precisely with the local onset of the Agricultural
Revolution in Europe.
Conclusions from isotope studies. The isotope systems
that have been studied thus far in hominin bone and teeth
provide evidence that early hominins were opportunistic
feeders
(257)
. The spread of C
4
foods in East Africa, and sub-
sequently in the hominin food chain between 3 and 4 Mya,
is in agreement with a niche of early hominins that locates
close to the water. This conception is in agreement with
the palaeo-environmental evidence. However, many ques-
tions still remain unanswered. With regard to the possible
niche in the waterland interface, it seems interesting to
include aquatic as well as terrestrial piscivorous animals
into future studies. The data of combined studies of early
hominins and the more recent hominins suggest a gradual
increase in dietary animal protein, a part of which may
derive from aquatic resources. In the more recent human
ancestors, a substantial part of the dietary protein was irre-
futably derived from marine resources, and this habit was
only abandoned in some cases after the introduction of
agriculture at the onset of the Neolithic
(254)
.
Archeology
The oldest stone tools found so far are dated to 2·6
Mya
(258,259)
and it has been suggested that these were
used for flesh removal and percussion on long bones for
marrow access. From this time onward stone tools were
apparently used for defleshing and butchering of large ani-
mals. However, again there is a pitfall in putting too much
emphasis on the association between stone tools and hunt-
ing and butchering of large animals as the sole food source
of the human ancestors, especially with regard to brain
foods such as LCP. As stated by Liem’s paradox; the appar-
ently overwhelming evidence for the consumption of bone
marrow, or even brain from cracked skulls, by the findings
of cut marks on animal bone may not be evidence for the
primary food resources of human ancestors, but only for its
fallback food. Bones, especially long bones, are also better
preserved than vegetable material. Moreover, cut marks on
bone are easier ascribed to human utilisation than any
nearby found fossilised fish bones or molluscan shells
that only seldomly bear cut marks
(260,261)
and are often
not even examined. Hence, while human remains are
nearly always found in the vicinity of water and the fossil
record of nearby found fish is extensive
(74,262)
, the exploi-
tation of aquatic resources is difficult to relate to early
man
(263)
.
The present review is about the diet that allowed early
humans to increase their brain size and thereby become
intelligent enough to develop, for example, symbolic
thinking and the controlled use of fire. Hunting and/or
scavenging is often invoked as an important source of
LCP, but, as pointed out by Crawford
(2)
, even in the
more recent certainly ‘hunting’ ancestors ‘a [scavenged]
small brain was not going to go far among the ladies
[and children] even if it was still in an edible condition
when they [the male hunters] got it back [from the
savanna]’
(2)
, not even in the scenario
(264)
that we were
specialised, as suggested
(265)
, in endurance running.
Apart from organ tissue (liver and brain) and bone
R. S. Kuipers et al.110
Nutrition Research Reviews
marrow (whether scavenged or hunted), fish, shellfish and
other aquatic foods are also mentioned as rich sources
of the nutrients involved in brain expansion
(99,130,266)
.
Therefore, the question arises whether the archeological
evidence for human habitation in the landwater ecosys-
tem only represents facilitated fossilisation or indicates
the true ecological niche. The following section will
focus on comparable evidence for the concurrent exploi-
tation of aquatic resources.
Living in the waterland ecosystem. Because sea
levels have risen up to 150 m in the past 17 000 years, a
substantial part of the evidence for the exploitation of
aquatic resources is hidden below sea level, if not perma-
nently destroyed by the water
(267,268)
. However, in Kenya,
a site in East Turkana provides solid evidence that at about
1·95 Mya hominins enjoyed carcasses of both terrestrial and
aquatic animals including turtles, crocodiles and fish,
which were associated with Oldowan artifacts
(261)
. More
ambiguous evidence for the exploitation of freshwater
fish, crocodiles, turtles, amphibians and molluscs by
Homo habilis in the Olduvai Gorge in Tanzania goes
back as far as 1·81·1 Mya
(267,269)
. Subsequent tentative
evidence from the Olduvai Gorge dates the use of similar
aquatic resources by Homo erectus to 1·1 0·8
Mya
(267,269)
. Also the out-of-Africa diaspora probably took
place largely via the coastlines
(81)
, even after the crossing
of the Bering Strait into North America
(270)
(Fig. 2). In
Koa Pah Nam, Thailand, 700 000-year-old piles of fresh-
water oyster shells were associated with Homo erec-
tus
(271,272)
. In Holon, Israel, freshwater turtles, shells and
hippopotamus bones were associated with Homo erectus
and dated to 500400 Kya
(273)
.Homo erectus fossils associ-
ated with seal remains in Mas del Caves (Lunel-Viel,
France) were dated to 400 Kya
(274)
.
The archeological evidence for aquatic resource use
increases with the appearance of archaic Homo
sapiens
(267)
. Although dominated by land mammal
bones, 400 000– 200 000-year-old remains from penguin
and cormorants in Duinefontein, South Africa were associ-
ated with early Homo
(275)
. Shellfish and possibly fish
remains, dated 300230 Kya, were associated with the
French coastal campsite at Terra Amata
(276,277)
, while
marine shellfish and associated early human remains,
dated 186–127 Kya, were found in Lazaret, France
(274)
.
Marean et al.
(278)
found evidence for the inclusion of
marine resources, at 164 Kya, in the diet of anatomically
modern humans from the Pinnacle Point Caves (South
Africa). At the Eritrea Red Sea coast, Middle Stone Age arti-
facts on a fossil reef support the view that early humans
exploited near-shore marine food resources by at least
125 Kya
(279)
. In several North African sites, dated to
40–150 Kya
(267)
, human remains were associated with
shell middens and aquatic resources such as aquatic
snails, monk seals, mussels and crabs. Several European
sites, dated to 30125 Kya, are comparable with archeolo-
gical sites that reveal evidence ranging from thick layers of
mussels and large heaps of marine shells in Gibraltar
(267)
to
diverse marine shells in Italy
(280)
, and to a casual descrip-
tion of the presence of marine shells of unknown density
in Gruta da Figueira in Portugal
(267)
. Further evidence for
the use of shellfish, sea mammals and flightless birds
comes from: Klasies River Mouth (South Africa) dated
between 130 and 55 Kya
(267,281,282)
; from Boegoeberg,
where 130 000 – 40 000-year-old shell middens and cormor-
ant bones were associated with Homo sapiens
(267,283)
; from
Herolds Bay Cave, where 120 000 – 80 000-year-old shell
middens, shellfish, mussels and otter remains were associ-
ated with human hearths
(267)
; from Die Kelders (7555
Kya), where abundant remains of sea mammals, birds
and shellfish were found in cave deposits
(267,284)
; and
from Hoedjies Punt (7060 Kya), Sea Harvest (70–60
Kya) and Blombos Cave (6050 Kya) for the use of shell-
fish, sea mammals and fish
(267,285)
. From this period
onwards, human settlements are strongly associated with
the exploitation of aquatic resources
(267,268,282,286 – 288)
. Evi-
dence for more sophisticated fishing by use of barbed
bone harpoon points dates back to 9075 Kya in Katanda,
Semlike River, Zaire
(289,290)
and to 70 Kya in South
Africa
(291)
. Finally, indications for seafaring are dated to
42–15 Kya
(292 – 294)
. Possibly, seafaring dates as far back
as 800 Kya, as indicated by the finding of Homo erectus
stone tools at the Indonesian island of Flores, which is
located on the other side of a deep sea strait
(79,295 – 299)
.
In general, many archeological sites are found along chan-
nels, lake- and seashores
(99,266,267,282)
and reveal aquatic
fauna, such as catfish, crocodile and hippopotamus
(300)
,
but its proves difficult to relate their possible utilisation
to our early ancestors.
Several events within the time span of the past about 2
million years have been attributed to the increase in
brain size and intelligence. The introduction of meat in
the hominin diet, which resulted in a higher dietary quality,
has been discussed above. Claims for controlled fire in the
Olduvai Gorge (Tanzania) and Koobi Fora (Kenya) go as
far back as 1·5 Mya
(215,301,302)
. Evidence for cooking is as
old as 250 Kya
(301)
, but possibly dates back to 800
Kya
(303)
, when indications of controlled fire were found
to be present. However, recently it has been concluded
that solid evidence for systematic use of fire is only
found from 400 to 300 Kya onwards
(304)
. Evidence that
cooking provided increased dietary quality was recently
provided by Wrangham et al.
(215)
. According to archeo-
logical evidence, this could only have played an important
role since the appearance of Homo sapiens
(215,301)
and
Neanderthals
(305)
. Also, the inclusion of aquatic resources
as an attributor to human brain evolution has been
suggested
(2,99 – 101,130,266,306 – 308)
, but remains a matter of
debate
(134,135,268,309)
.
From huntinggathering to agriculture. The hunter
gatherer lifestyle continued worldwide for several millions
of years and ended quite abruptly with the introduction
of agriculture. The first indications for the abandonment
Palaeolithic nutrition for disease prevention 111
Nutrition Research Reviews
of the huntergatherer lifestyle towards settlement come
from a 23 000 year-old fisher – hunter– gatherer’s camp at
the shore of the Sea of Galilee
(310,311)
. The associated
return from diets containing substantial amounts of protein
(from hunting and gathering) back to substantial amounts
of carbohydrates is supported by indications for the
ground collecting of wild cereals
(312)
. This was slowly fol-
lowed by the large-scale utilisation of cereals starting with
the onset of the Agricultural Revolution some 10 Kya.
As indicated above (see ‘Biogeochemistry’), there is
much controversy about the diet of the earliest humans
and until now it is often stated that fishing was only intro-
duced until more recently. From an anthropological per-
spective this might be true, since certain types (for
example, deepwater) of fishing require advanced tech-
niques
(294)
. However, from a nutritional point of view,
‘fishing’ might include anything from collecting sessile
shellfish to the seasonal hand capture or clubbing of
migrating or spawning fish in very shallow water. Since
fresh drinking water is the single most important aquatic
resource for humans, hominins probably observed preda-
tors and scavengers feeding on aquatic animals. This
makes it unlikely that they would not have participated
in opportunistic harvesting of the shallow-water flora and
fauna, such as molluscs, crabs, sea urchins, barnacles,
shrimp, fish, fish roe or spawn, amphibians, reptiles,
small mammals, birds or weeds
(175,267)
. There are many
indications suggesting that the evolution of early Homo
and its development to Homo sapiens did not take place
in the ‘classical’ hot, arid and waterless savanna, but
occurred in African ecosystems that were notably located
in places where the land meets the water (with the land
ecosystem possibly consisting of depending on rainfall
wooded grasslands). Compared with terrestrial hunting
and/or scavenging in the savanna, food from this land
water ecosystem is relatively easy to obtain and is rich in
the aforementioned combination of haem-Fe, iodine, Se,
vitamins A and D, and long-chain n-3-fatty acids
(100,101,266)
.
In conclusion, there is ample archeological evidence for
a shift from the consumption of plant towards animal
foods. Second, although there is an extensive archeological
record for aquatic fossils (representing possible food) in
the vicinity of human remains, their co-occurence is
usually attributed to the preferential conservation of
human remains in the vicinity of water. The present
review provides support for the notion that the exploita-
tion of these aquatic resources by hominins in coastal
areas should be the default assumption, unless proven
otherwise
(154)
. For a long time period in hominin evol-
ution, hominins derived large amounts of energy from
(terrestrial and aquatic) animal fat and protein. This habit
became reversed only by the onset of the Neolithic
Revolution in the Middle East starting about 10 Kya.
Anthropology
The huntergatherer diet. The Homo genus has been on
earth for at least 2·4 million years
(313)
and for over 99 % of
this period has lived as hunter gatherers
(314)
. Surprisingly,
very little information is available on the macro- and micro-
nutrient compositions of their diet in this extended and
important period of human evolution
(34,148)
. Since the
onset of agriculture, about 10 Kya, agriculturalists and
nomadic pastoralists have been expanding at the expense
of hunter–gatherers
(314)
, with agricultural densities increas-
ing by a factor of 10 1000 compared with the highest
hunter densities. For this reason, present-day hunter
gatherers are often found in marginal environments,
unattractive for crop cultivation or animal husbandry.
In order to study the original huntergatherer way of
life, it is appropriate to aim at the few hunter gatherer
communities living in the richer environments that bear
closer resemblance to those in which the evolution of the
genus Homo probably took place. Most studies on
hunter–gatherers and their diets are, however, performed
by anthropologists
(315)
, whose primary interests are differ-
ent from those of nutritionists. Anthropologists would, for
example, conclude that ‘fishing was so unimportant as to
be a type of food collection’
(316)
, or consider collecting
both small land fauna and shellfish
(314)
as part of ‘gather-
ing’, whereas from a nutritional point of view considerable
differences exist in energy density, macro- and micro-
nutrient composition between plants, terrestrial and
aquatic animal foods.
Hunting v. gathering. Studies on food procurement of
present-day huntergatherer societies show, in terms of
energy gain v. expenditure, the advantage of hunting com-
pared with plant foraging
(192)
. Nevertheless, three distinct
studies
(41,148,314)
showed that hunting makes up only
about 35 % of the subsistence base for worldwide
hunter–gatherers, independent of latitude or environment.
However, collection of small land fauna and shellfish was
included as gathering in these studies. While gathering evi-
dently played an important role over the whole of human
evolution, hunting, although introduced later, coincided
with ‘a major leap for mankind’ and has ever since
played the most dominating cultural role. While hunting
may have overtaken gathering in cultural importance, gath-
ering continued to play a very important nutritional role,
because: (i) gathering still contributes about 65 % to the
subsistence base; (ii) many micronutrients derive only
from plant sources; (iii) gathering of, for example, shellfish
provides a substantial amount of LCP and other nutrients
essential for brain development; and (iv) gathering plays
an important cultural role since women, children and
grandparents can participate
(56,57,317)
.
Contrary to common belief, hunting in present-day
hunter–gatherers is still not very successful: the probability
for a kill in !Kung bushmen is only 23 %
(314)
and the sub-
sistence of Hadza, as described by Marlowe
(41)
and
R. S. Kuipers et al.112
Nutrition Research Reviews
Woodburn
(145)
, is composed of 75–80 % of plant foods.
Conversely, studies of North American huntinggathering
societies describe the dietary role of shellfish as similar to
‘bread and butter’, being the staple food
(318)
in these
societies. The anthropological remark
(314)
that for many
studied huntergatherer tribes ‘fishing was only a type of
food collection’ also adds to the notion that the collection
of aquatic foods might have preceded scavenging and
hunting. Collecting aquatic foods is still daily practice in
Eastern Africa and picking up, clubbing or spearing
stranded aquatic animals seems much easier and safer
than either scavenging or hunting game on the Serengeti
plains.
We conclude that gathering plays, and most likely always
played, the major role in food procurement of humans.
Although hunting doubtlessly leaves the most prominent
signature in the archaeological record, gathering of veg-
etables and the collection of animal, notably aquatic,
resources (regardless of whether their collection is con-
sidered as either hunting or gathering), seems much
easier compared with hunting on the hot and arid savanna.
We suggest that it seems fair to consider these types of
foods as an important part of the human diet, unless
proven otherwise
(154)
. Conversely, while hunting might
have played a much more important role at higher lati-
tudes, dietary resources in these ecosystems are rich in
n-3-fatty acids (for example, fatty fish and large aquatic
mammals), while the hominin invasion of these biomes
occurred only after the development of more developed
hunting skills.
(Patho)physiology
Brain-selective nutrients. Nutrients and other environ-
mental factors are increasingly recognised to influence epi-
genetic marks
(319 – 323)
, either directly or indirectly via many
bodily sensors. Food from the diverse East African aquatic
ecosystems is rich in haem-Fe, iodine, Se, vitamins A and
D, and n-3 fatty acids from both vegetable origin and
fish
(101)
. All of these nutrients seem to act at the crossroad
of metabolism and inflammation
(24)
. For example,
PPAR
(324,325)
are lipid-driven nuclear receptors with key
cellular functions in metabolism and inflammation
(26)
.
TR
(326)
, VDR
(327)
, RXR and RAR
(328)
are other examples of
nuclear transcription factors that serve functions as
ligand-driven sensors. The iodine- and Se-dependent hor-
mone triiodothyronine (T
3
)
(329 – 331)
is a ligand of TR
(326)
,
many fatty acids and their derivatives are ligands of
PPAR
(332)
, the vitamin D-derived 1,25-dihydroxyvitamin D
hormone is a ligand of the VDR
(333)
,9-cis-retinoic acid
and the fish oil fatty acid DHA are ligands of RXR
(328)
,
while RAR interacts with vitamin A (retinol) and many of
its derivatives such as all-trans-retinoic acid, retinal and
retinyl acetate
(328)
. The ligated nuclear transcription factors
usually do not support transcription by themselves, but
need to homodimerise or heterodimerise notably with
RXR to facilitate gene transcription. Examples of the latter
are TR/RXR, PPAR/RXR, VDR/RXR and RAR/RXR. It has
become clear that their modes of action illustrate the
need of balance between, for example, iodine, Se, fish
oil fatty acids and vitamins A and D, a balance that is nota-
bly found in the landwater ecosystem.
Deficiencies of the above ‘brain-selective nutrients’ are
among the most widely encountered in the current world
population
(101,334)
. While iodide is added to table salt in
many countries, margarines and milk have become popu-
lar food products for fortification with vitamins A and
D. After discussing some general health differences
between traditionally living individuals and those living
in Westernised countries, we focus on the importance of
LCP and notably those of the n-3-series, as examples of
the above-mentioned nutrients that are especially abun-
dant in the landwater ecosystem.
Hunter–gatherer v. ‘Western’ physiology. There are
many differences in health indicators between traditionally
living individuals and those living in Western societies. For
instance, primary and secondary intervention trials with
statins indicate lowest CHD risk at an LDL-cholesterol of
500 –700 mg/l (1·3– 1·8 mmol/l), which is consistent with
levels encountered in primates in the wild and hunter
gatherer populations with few deaths from CVD
(335 – 339)
.
Another example of the healthy lifestyle of present-day
hunter–gatherers comes from the observed ‘insulinopenia’
or ‘impaired insulin secretion’ following an oral glucose
tolerance test (Fig. 6) in Central African Pygmies and
Kalahri Bushmen
(340,341)
, respectively. As opposed to the
‘impairments’ noted by these authors, it may also be
argued that these researchers were actually witnessing an
insulin sensitivity that has become sporadic in Western
countries as a consequence of the decrease in physical
activity and fitness, increase in fat mass and as a result of
the quantity and quality of the foods consumed
(36,133,342)
.
The current consensus is that ‘fat is bad’ and especially
saturated fats have become associated with CVD
(343 – 345)
.
However, traditional Maasai consumed diets high in protein
and fat (milk and meat) and low in carbohydrates
(346,347)
.
They had high intakes of saturated fat and cholesterol,
showed extensive atherosclerosis with lipid infiltration and
fibrous changes, but had very few complicated lesions,
and were virtually devoid of CVD
(348)
. The average total
and LDL-cholesterol in these societies was low and did not
increase with age
(348)
. Finally, the physical fitness of indi-
viduals in such traditional societies, such as the Maasai,
is often remarkable
(337)
.
In Kalahari Desert Bushmen and Central African
Pygmies, observers could not find any case of high blood
pressure and blood pressure did not increase with
age
(335,349)
. Dental surveys of Kalahari Bushmen
(350)
and
other hunter–gatherers
(49)
showed a remarkable absence
of caries. The absence was explained by the repe-
titive annual abstinence of fermentable sugars in their
diet, with a consequent inability to build a cariogenic oral
Palaeolithic nutrition for disease prevention 113
Nutrition Research Reviews
Lactobacillus flora
(350)
. Inhabitants of Kitava (Trobriand
Islands, Papua New Guinea) have high intakes (70 en%)
of carbohydrates from yams, high intakes of SFA from
coconuts, and a high fish intake
(44,45,351)
. Although both
high intakes of carbohydrates and saturated fat have
been related to the metabolic syndrome and CVD, these
traditional Kitavians do not show symptoms of either the
metabolic syndrome and are virtually free from the Western
diseases that ensue from it.
Evidence-based medicine as applied to long-chain
PUFA in CVD and depression. Despite some compelling
examples of the healthy lifestyles of traditional populations,
current dietary recommendations derive preferably from
randomised clinical trials with single nutrients and pre-
ferably hard endpoints
(352)
. This approach clearly over-
simplifies the effects of dietary nutrients
(353)
, since neither
macronutrients, nor micronutrients, are consumed in iso-
lation and their effects may be the result of a complex web
of interactions between all the nutrients present in the
biological systems that we consume, such as a banana
or a fish.
The current recommendations from many nutritional
boards for a daily intake of 450 mg EPA þDHA in adults
derive from epidemiological data that demonstrated a nega-
tive association of fish consumption with CHD
(354 – 357)
that
has subsequently become supported by landmark trials
with ALA
(358)
and fish oil
(359 – 361)
in CVD. However, not all
trials in CVD have been positive
(362)
. In addition, a negative
association was observed for fish consumption and
depression
(363 – 365)
and for homicide mortality
(366)
. The
causality of these relationships was supported by some,
but not all, trials with fish oil in depression
(367 – 371)
, while a
recent meta-analysis demonstrated the beneficial effect of
EPA supplements with $60 % EPA of total EPA þDHA in
a dose range of 200 –2200 mg/d of EPA in excess of DHA
(372)
.
The influence of polymorphisms in the genome is
increasingly recognised, but seldom interpreted in an evol-
utionary context. As argued above, most polymorphisms
were already amongst us when Homo sapiens emerged,
some 200 Kya, while that also holds true for most, if
not all, currently identified ‘disease susceptibility genes’
that are usually abundant but confer low risk
(373)
.
10·0
9·0
8·0
7·0
6·0
5·0
4·0
3·0
2·0
1·0
0·0
0 20406080100
100
90
80
70
60
50
40
30
20
10
0
120
Time after glucose intake (min)
Plasma glucose (mmol/l)Plasma insulin (µU/l)
140 160 180 200
0204060
(b)
(a)
80 100 120
Time after glucose intake (min)
140 160 180 200
Fig. 6. ‘Abnormal’ insulin response but normal glucose response after oral glucose tolerance test in African Bushmen and Pygmies, compared with Western con-
trols. (a) Plasma glucose response after an oral glucose load of 50 g (Bushmen (V) and white controls (W)) or 100 g (Pygmy (B), Pygmy with 2 weeks’ daily sup-
plementation of 150 g carbohydrates before testing (O), Bantu (X) and American controls ( )). Of note is that Bushmen and Pygmies have significantly lower body
weights as compared with Bantu and white and American controls (average weight Bushmen/Pygmy males 46 kg, females 38 kg; controls 65 kg), while each
group received the same unadjusted loading dose of 50 g or 100 g glucose. (b) The so-called ‘abnormal’ insulin response or ‘impaired’ insulin secretionas
observed by the authors in both Bushmen and Pygmies
(340,341)
.
R. S. Kuipers et al.114
Nutrition Research Reviews
A loss-of-function mutation in a specific biosynthetic path-
way might be an evolutionary advantage if the specific
endproduct has been a consistent part of the diet, such
as is probably applicable to all vitamins, for example,
vitamin C
(374,375)
. Applied to our LCP status, it is nowadays
well established that all humans synthesise DHA with
difficulty
(376,377)
. Analogously, the recently discovered
polymorphisms of fatty acid desaturases 1 (FADS1; also
named D-5 desaturase) and FADS2 (D-6 desaturase) with
lower activities in their conversion of the parent essential
fatty acid to LCP suggest that from at least the time of
their appearance, the dietary intakes of AA, EPA and
DHA have been of sufficient magnitude to balance the
LCP n-3:LCP n-6 ratio
(378,379)
to maintain good health.
Long-chain PUFA benefits in pregnancy and early life.
Another indication for the importance of LCP comes from
the higher LCP contents in the fetal circulation compared
with the maternal circulation, a process named biomagnifi-
cation
(380 – 382)
, which occurs at the expense of the maternal
LCP status
(383,384)
. The decreasing maternal n-3 LCP status
during pregnancy in Western countries is associated with
postpartum depression
(363,364)
, although intervention
studies with LCP in postpartum depression have been
negative so far
(370,371,385,386)
. However, a positive effect
was seen for n-3 LCP supplementation on depression
during pregnancy
(387)
and it has been advocated to start
supplementation earlier in pregnancy and with higher
dosages
(388)
.
Maternal LCP intakes have also been related to infant
health. AA and DHA in premature and low-birth-weight
infants correlated positively with anthropometrics, AA
to increased birth weight
(389)
and DHA to prolonged
gestation
(390 – 392)
. Studies with supplementation of DHA
during pregnancy yielded, for example, evidence for:
(i) the maturation of the brain, visual system and retina
of the newborn at 2·5 and 4 months, but not at
6 months
(393 – 397)
; (ii) increased problem solving at 9
months but no difference in memory
(398)
; and (iii) superior
eye–hand coordination at 2·5 years
(399)
and higher intelli-
gence quotient at 4 years
(400)
but not at 7 years of
age
(401)
. In contrast to the inconclusive human studies,
animal studies and combined human and animal studies
showed abnormal behaviour together with disturbed cog-
nition at lower brain DHA levels
(402)
. The importance of
dietary AA during pregnancy seems less pronounced, but
a positive association between umbilical AA and neonatal
neurological development
(389)
and a lower venous AA for
those with slightly abnormal neurological development
(403)
has been shown. A reduced DHA status in the brain is
associated with a mildly increased AA status
(404)
, which is
in its turn associated with low-grade inflammation
(405)
.
Infant health starts with maternal health; thus dietary
recommendations issued for pregnant women indirectly
also apply to their infants. The recommendation for
adults to consume 450 mg DHA þEPA per d translates into
a DHA composition in breast milk of about 0·79 %
(406)
.
However, current recommendations for the composition
of infant formulae derive mainly from the range of
human milk fatty acid compositions as observed in Western
countries, which in their turn derive from women with
recorded intakes below the 450 mg recommended daily
intake of EPA þDHA
(407,408)
.
The same paradox holds for other fatty acids in breast
milk. For instance, there are few recommendations for
the medium-chain SFA (MCSFA) content of human milk.
High MCSFA contents in some traditional societies derive
from their high intakes of 12 : 0 and 14 : 0 from coco-
nuts
(409)
. Conversely, the high MCSFA contents in
Western populations are primarily influenced by maternal
carbohydrate intakes
(410)
, since the mammary gland
has the unique ability to convert glucose into MCSFA
(6 : 0 –14 : 0), mainly lauric (12 : 0) and myristic (14 : 0)
acids. However, women with regular consumption of coco-
nuts have a much higher 12 : 0:14 : 0 ratio compared with
women with high carbohydrate intakes. Both MCSFA are
readily absorbed in the gastrointestinal tract, while antiviral
as well as antibacterial properties have been attributed to
some MCSFA, but mainly to 12 : 0
(411,412)
.
The PUFA content of Western milk has increased over
the last decades
(413,414)
. While the human milk LA content
in the USA increased by at least 250 %, its DHA content
decreased by almost 50 %
(414)
. The (from an evolutionary
point of view) abnormally high LA intake is, despite a
lack of evidence
(415)
, advocated for cardiovascular
health
(416)
. The resulting high LA status is likely to interfere
with both the incorporation of AA and DHA into phospho-
lipids and also inhibits their synthesis from their parent
essential fatty acid
(417)
. Major differences are noted in the
comparison of the human milk fatty acid compositions of
Western mothers compared with some traditional African
women
(409,418)
, with unknown consequences for infant
health or the occurrence of disease at adult age (i.e. the
‘Barker hypothesis’)
(16,419)
. It has been proposed that the
high concentrations of EPA, DHA as well as AA in human
milk, such as described for many fish-consuming
societies
(409,420,421)
, might be a more appropriate reflection
of the Palaeolithic breast milk composition and may
therefore constitute a better reference for infant formulae
than do Western human milks
(422)
.
The influence of environment. It is estimated that 70 %
of all cases of stroke and colon cancer, 80% of all CVD and
90 % of all cases of type 2 diabetes mellitus have been
caused by lifestyle and could have been prevented by
paying more attention to modifiable behaviour factors,
including specific aspects of diet, overweight, inactivity
and smoking
(423)
. The mismatch between the human diet
and the Palaeolithic genome might therefore be respon-
sible for many typically Western diseases. In addition to
the evidence from many other disciplines, evidence from
(patho)physiology and epidemiology adds to the notion
that a great deal of information on healthy diets might
derive from the study of the diets of the early human
Palaeolithic nutrition for disease prevention 115
Nutrition Research Reviews
ancestors. The metabolic syndrome, characterised by
impaired insulin sensitivity, is at the centre of many dis-
eases of civilisation. High intakes of refined carbohydrates
as well as low intakes of LCP have been implicated in the
development of insulin resistance. As such, low carbo-
hydrate intakes
(424,425)
and high LCP
(8,34,426,427)
intakes
by the early human ancestor might explain in part the
low incidence of diseases of civilisation in current
hunter–gatherer societies. The available evidence from
pathophysiology and epidemiology supports the hypoth-
esis that the landwater ecosystem contributed important
and indispensable nutrients to evolving hominins.
Dietary reconstruction of the nutrients available
in Eastern Africa
The debate on the ecological niche of human ancestors is
unlikely to reach a consensus shortly. The millions of years
of human evolution concurred with marked and abrupt cli-
matic changes, which renders a single ecological niche of
human ancestry unlikely. However, it is at the same time
clear that in a short period of time humans have made
tremendous changes in their lifestyle, their diet included,
that lie at the basis of the diseases of Western civilisation.
This prompted various investigators to reconstruct the
possible compositions of diets that could have been
consumed by our Palaeolithic ancestors. Their studies
are, for example, based on the plausibility that before the
Agricultural Revolution, when humans lived as hunter
gatherers, cereals were no appreciable part of the diet
and that wild animals living in the Eastern African savanna
and in Eastern African aquatic ecosystems have different
fatty acid compositions compared with the domesticated
animals that have now become staple foods. For example,
the lean savanna animals that inhabit the Eastern African
plains have much lower fat contents, and the available
fat is much more enriched in PUFA
(428)
. Similarly, high-
latitude (fatty) fish have much higher EPA and DHA con-
tents, but lower AA contents compared with low-latitude
(lean) fish from tropical waters
(429 – 432)
.
Eaton & Konner
(8)
where the first to use this approach in
reconstructing a Palaeolithic diet; their pioneer study was
published in the New England Journal of Medicine in
1985. The authors estimated that late Palaeolithic humans
consumed diets containing 35 % meat and 65 % vegetable
foods, containing 34 en% from protein, 45 en% from carbo-
hydrate and 21 en% from fat, while the ratio between poly-
unsaturated and saturated fat equalled 1·41 and their fibre
intake amounted to 46 g/d
(8)
. These outcomes contrasted
with the average American diet at the time, that consisted
of 12 en% protein, 46 en% carbohydrate and 42 en% fat,
with a polyunsaturated:saturated fat ratio of 0·44 and a
fibre intake of 20 g/d. After 25 years of additional study,
Konner & Eaton confirmed their previous findings by esti-
mating that the Palaeolithic diet provided 2530 en% pro-
tein, 3540 en% carbohydrate and 20– 35 en% fat
(433)
,
while the polyunsaturated:saturated fat ratio was 1·40
(434)
.
Moreover, they concluded that ‘it has become clear since
our initial publications that marine, lacustrine, and riverine
species were important sources of animal flesh during the
evolution of modern Homo sapiens, and may have played
a role in the evolution of brain ontogeny’
(433)
. In addition
to the earlier studies, they also estimated the vitamin and
mineral composition of a Palaeolithic diet, showing
higher contents of folate, riboflavin, thiamin, vitamins A
and E, Ca, Mg, P, Zn, and notably ascorbate, vitamin D
(sunlight), Cu, Fe, Mn and K, while the Palaeolithic diet
contained much lower Na compared with contemporary
US intakes and recommendations
(433 – 435)
. In a subsequent
study they estimated that in different ancient hunting and
gathering populations, fatty acid intakes would have
ranged from 5·19 to 20·6 g LA/d, 0·26 to 4·8 g AA/d, 3·45
to 25·2 g ALA/d and 0·03 to 1·52 g DHA/d, which contrasted
with the much higher LA (22·5 g/d) and lower ALA (1·2 g/d),
AA (0·6 g/d) and DHA (0·08 g/d) intakes as observed in
current Western populations
(34)
.
In a meticulous analysis of worldwide huntergatherer
diets, Cordain et al.
(148,436)
estimated that the most plaus-
ible percentages of total energy from dietary macronutri-
ents would be 19–35 en% from protein, 2240 en% from
carbohydrate and 2858 en% from fat, which reflects a
markedly higher contribution of dietary fat, a similar
amount of protein, but a lower contribution of carbo-
hydrates, compared with earlier estimates from Eaton &
Konner
(8,434)
. The main differences were explained by
the assumption that, wherever it was ecologically possible,
hunter –gatherers would have consumed 45 – 65 % of
total energy from animal foods
(148)
, while in the earlier
estimations
(8,434)
only 35 % derived from animal foods.
These higher animal food intakes were explained by
their inclusion of both worldwide hunting and fishing
huntinggathering societies into their new calculation
models
(148)
, also including mounted and arctic hunters.
Those latter possibilities, however, seem insignificant
with regard to early human evolution, which explains
why they seem to overestimate the amount of the
diet that is derived from animal foods. For example,
Marlowe
(41)
estimated that in a warm-climate sample
about 53 % of the diet derives from gathering, 26 % from
hunting and 21 % from fishing (i.e. about 47 % from hunting).
To subsequently investigate the nutrient compositions of
such diets, fish consumption was incorporated as a separ-
ate variable to plant and meat consumption in the earlier
models, since aquatic and terrestrial animals have mark-
edly different fatty acid compositions. In this most recent
analysis
(437)
, 12 500 kJ (3000 kcal) Palaeolithic diets were
investigated with plant:animal food intake ratios ranging
from 70:30 to 30:70 en%/en% under the conditions
of four different foraging strategies in which the animal
part ranged from exclusive meat consumption including
the selective consumption of energy- and LCP-rich fat
from bone marrow and brain, respectively
(427)
, to the
R. S. Kuipers et al.116
Nutrition Research Reviews
consumption of an entirely aquatic diet in an Eastern Afri-
can water–land ecosystem
(438,439)
. It was found that that
the energy intakes from the macronutrients were: 25– 29
en% (range 8–35) from protein, 39 40 en% (range
19–48) from carbohydrate and 30 39 en% (range 20–72)
from fat. Dietary LA ranged from 1·7 to 6·2 en%/d, AA
from 1·15 to 10·7 g/d, ALA from 2·1 to 5·8 en%/d and
EPA þDHA intakes from 0·87 to 28·3 g/d
(437)
. From
these data, despite their wide range in outcomes, it can
again be concluded that there are substantial differences
with respect to the average composition of the current
Western diet, notably because of its higher proportions of
carbohydrates and LA, and its much lower protein and
ALA and LCP contents. It became also conceivable that
ancestors living in the East African waterland ecosystem
had daily intakes of gram amounts of EPA þDHA. As
such, these n-3 LCP intakes were comparable with those
of the traditionally living Eskimos in Greenland, who
because of their low CVD risk
(354,355)
initiated the current
interest in the role of n-3 LCP in both primary and second-
ary prevention of CVD. In addition to these n-3 fatty acids,
the water–land ecosystem is also a rich source of haem-Fe,
iodine, Se and the vitamins A and D
(101)
, which have
important functions and interactions in gene transcription
and metabolism
(24,26,440)
.
Dietary changes since the Agricultural Revolution
Whatever the specific composition and wide range of
early hunter–gatherer diets, the current consensus is that
our diet has changed markedly from the time of large-scale
utilisation of cereals and animal domestication (i.e. the
Agricultural Revolution) starting some 10 Kya. Contrary to
earlier belief, the advent of agriculture coincided with an over-
all decline in nutrition and general health, but at the same
time provided an evolutionary advantage since it increased
birth ratesand thereby promotednet population growth
(49,50)
.
While the decline of nutritional quality and general
health started with the onset of the Agricultural Revolution,
these processes became even more pronounced with the
advent of the Industrial Revolution some 100200 years
ago
(9,11,133)
. Among the many dietary and lifestyle changes
(Fig. 7) are: a grossly decreased n-3:n-6 fatty acid ratio, the
combined high intakes of SFA and carbohydrates
(441 – 443)
,
the introduction of industrially produced trans-fatty acids,
reduced intakes of n-3 and n-6 LCP, reduced exposure to
sunlight, low intakes of vitamins D and K, disbalanced anti-
oxidant status and high intakes of carbohydrates with high
glycaemic indices and loads, such as sucrose and indus-
trially produced high-fructose maize syrup
(36,133,444,445)
.
Many of these changes act in concert, which points at
the serious limitations of conclusions from contemporary
investigations that study the many nutrients in isolation
and form the basis of modern nutritional guidelines.
An example is the interaction of dietary carbohydrates
with SFA
(441 – 443,446)
.
Potential benefits of a Palaeolithic diet
Evidence for the beneficial effects of Palaeolithic diets may
derive from their influence on weight reduction and classi-
cal coronary artery disease risk factors. In an uncontrolled
study with healthy adults, Osterdahl et al.
(447)
showed a
decrease in weight, BMI and waist circumference after
3 weeks ad libitum consumption of a Palaeolithic-like
diet (i.e. 6627 kJ/d (1584 kcal/d); carbohydrate 40, protein
24, fat 36 en%), compared with their baseline usual diet
(10 368 kJ/d (2478 kcal/d); carbohydrate 54, protein 14,
fat 30 en%). Additionally, they showed favourable effects
on systolic blood pressure and plasminogen activator
inhibitor-1. Jo
¨nsson et al.
(448)
performed a cross-over
study of 2 £3 months in type 2 diabetic patients receiving
a Palaeolithic diet (6615 kJ/d (1581 kcal/d), carbohydrate
32, protein 24, fat 39 en%) or a diabetes diet (7858 kJ/d
(1878 kcal/d), carbohydrate 42, protein 20, fat 34 en%).
They showed a reduction of body weight, BMI and waist
circumference and lower HbA
1c
, TAG and diastolic blood
pressure, and higher HDL-cholesterol after consumption
of the Palaeolithic diet.
In a randomised trial in patients with IHD plus glucose
intolerance or type 2 diabetes, Lindeberg et al.
(449)
showed a reduced energy intake after ad libitum con-
sumption of a Palaeolithic diet (5623 kJ/d (1344 kcal/d);
carbohydrate 40, protein 28, fat 27 en%) as compared
with an ad libitum Mediterranean-like Consensus diet
(7510 kJ/d (1795 kcal/d); carbohydrate 52, protein 21, fat
25 en%). They also observed a larger improvement in glu-
cose tolerance in the Palaeolithic diet group, independent
of decreased waist circumference. The most convincing
evidence so far derives from an uncontrolled trial
(450)
showing that 10 d consumption of an isoenergetic Palaeo-
lithic diet (11 301 kJ/d (2701 kcal/d); carbohydrate 38,
protein 30, fat 32 en%) improved blood pressure, arterial
distensibility, insulin sensitivity and total, HDL- and LDL-
cholesterol in healthy sedentary human subjects, when
compared with their baseline usual diet (9924 kJ/d
(2372 kcal/d), carbohydrate 44, protein 18, fat 38 en%).
Dietary characteristics
that have changed
since the Agricultural and
Industrial Revolutions
Macronutrient
composition
Fatty acid
composition
Glycaemic
load
Fibre
content
Na:K
ratio
Acid–base
balance
Macronutrient
density
Fig. 7. The seven dietary characteristics that have been changed since the
Agricultural and Industrial Revolutions. Adapted from Muskiet
(24)
.
Palaeolithic nutrition for disease prevention 117
Nutrition Research Reviews
Importantly, there were no changes in energy intakes,
activity levels and body weight, which indicates that the
improved coronary artery disease risk profile was unrelated
to weight reduction or other well-known determinants.
Conclusions
The optimal nutrient combination to support good health
can be expected to reflect a certain balance. This balance
is present in the foods that were consumed by Palaeolithic
and possibly by pre-Palaeolithic ancestors, because it is this
balance on which the human genome has evolved. This
genome has been shaped by millions of years of evolution,
during which it adapted to the conditions of existence,
including the diet. There are ample indications from
many disciplines that the human ancestors evolved in a
water–land interface that provided food from both terres-
trial and aquatic resources. For instance, the availability
of both n-3 and n-6 LCP from the aquatic food chain was
one of the many factors that provided early humans with
the unique combination of brain-selective nutrients for
brain growth
(2)
. The recent deviation from this Palaeolithic
diet and lifestyle in general might be at the basis of many, if
not all, current diseases of civilisation. Detailed studies
with respect to the health effects of the diets of these earlier
ancestors are therefore warranted.
Acknowledgements
This research received no specific grant from any funding
agency in the public, commercial or not-for-profit sectors.
R. S. K. wrote the initial manuscript. After finishing a first
outline, all authors contributed to their specific fields of
knowledge, i.e. R. S. K. and F. A. J. M. refined the sections
‘Environment, nutrients and their interaction with the
genome’, ‘Evolutionary medicine’, ‘Arguments and counter
arguments in evolutionary health promotion‘, ‘Human
evolution’, ‘Dietary changes since the Agricultural Revolu-
tion’ and ‘Potential benefits of a Palaeolithic diet’ and the
sub-sections ‘Comparative anatomy’, ‘Biogeochemistry’,
‘Anthropology’, ‘(Patho)physiology’ and ‘Dietary recon-
struction of the nutrients available in Eastern Africa’; J. C. A. J.
refined the section ‘The probability of hunting on the
savanna’ and the sub-sections ‘Palaeo-environments’ and
‘Archeology’.
The authors thank Matt Sponheimer, Mike Richards and
Peter Ungar for their willingness to answer their questions.
There are no conflicts of interest.
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