Evolutionary history and nutrition – how personal does it get?

Eating healthy food is not as clear cut as you might think. When it comes to diet, what is ‘healthy’ and ‘unhealthy’ is highly dependent on the individual. The role of cultural adaptation can strongly influence genotype amongst individual groups of people on a micro-evolutionary scale. We need to consider how these changes affect the way individuals respond to certain kinds of food and the types of variation in responses amongst distinct populations.

The Weizmann Institute in Israel’s Personalised Nutrition Project investigated the variation in responses to a range of different food types from individual to individual. Each participant’s microbiome (the balance of micro-organisms or bacteria that live on and in your body) was analysed using stool samples to see what types of bacteria were present. The profiles and blood glucose responses of those studied varied wildly.

The preliminary results from the study involving 800 people revealed the there was incredibly high variability in how different people responded to the same foods. The study measured an individual’s blood glucose responses to both ‘healthy’ and ‘unhealthy’ foods. Surprisingly, while some people responded with spikes in blood glucose to supposedly high glycemic index foods, others did not produce any such spikes. The researchers then used an algorithm to produce tailored diets for individuals. Some conventionally unhealthy foods were fine for certain people to eat, and typically healthy foods were considered unsuitable for others.

The study did not take the participants’ ancestry into account. However, microbiome research is very much an emerging field within the spheres of archaeology and anthropology and has given some promising results with regards to variation between individual cultural groups. The University of Oklahoma’s Laboratories of Molecular Anthropology and Microbiome Research has produced some intriguing research working with ancient coprolite (excrement) samples and modern-hunter gatherer DNA.

Their research has revealed that the hunter-gatherer populations, whilst geographically isolated from each other, were much more similar in microbiome content than more agriculturalist populations adjacent to them. The microbe ‘Treponema sp.‘ which is associated with the digestion of fibrous plant materials is present in populations living a traditional lifestyle but absent in all of those living in industrialised societies. The microbe is also present in modern-day ape guts and in ancient coprolite samples. The lifestyle of modern humans has had a great impact on the way our microbiome is structured.

This invariably presents some massive implications for human health and disease. Autoimmune diseases such as multiple sclerosis, diabetes, and eczema are greatly influenced by our individual microbiomes. An understanding of what is beneficial and what is harmful to us through molecular anthropology and microbiota profiling would potentially solve some of the world’s biggest health problems. Running individual profiling as per the Weizmann Institute is likely to be too expensive for many people.

Therefore, the archaeological research discussed above is paramount in being able to provide widened accessed to understanding what might or might not be good for individual ethnic groups. This research could idealistically be used for production of guidelines for good and bad food groups for individual ethnic groups. The information could be distributed in a public health setting and stimulate a paradigm shift in the arena of the conventional recommended diet model.

References

Obregon-Tito, A., Tito, R., Metcalf, J., Sankaranarayanan, K., Clemente, J., Ursell, L., Zech Xu, Z., Van Treuren, W., Knight, R., Gaffney, P., Spicer, P., Lawson, P., Marin-Reyes, L., Trujillo-Villarroel, O., Foster, M., Guija-Poma, E., Troncoso-Corzo, L., Warinner, C., Ozga, A. and Lewis, C. (2015). Subsistence strategies in traditional societies distinguish gut microbiomes. Nature Communications, 6, p.6505.

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Alcohol Flush Reaction – can you handle your drink?

You may be able to drink through the night and wake up hungover yet sound, but for many people in the world consuming alcohol has an immediate and negative effect. The question as to whether or not our ancestors consumed alcohol has been met with some debate. The “Drunken Monkey Hypothesis” stems from the idea that primates other than Homo sapiens do consume fermented fruits that contain ethanol and, subsequently, enjoy the effects of alcohol consumption within nature. This has been argued by Dr Robert Dudley of UC Berkley as a potential reason for why humans have an affinity for alcohol and are prone to abuse it.

Within more recent historical evolution, our ability to process alcohol is variable amongst populations. Alcohol flush reaction results in a reddened appearance otherwise known as ‘Asian glow’ or ‘Asian flush’. It occurs more often in people with Asian heritage (40% rates of occurrence in Japanese populations, 26% in Korean populations, and 30% in Chinese/Taiwanese populations). While the reaction does occur in other populations, it is significantly rarer in frequency.

Presence of such a reaction is the result of lacking the chemical enzyme needed to properly process and breakdown alcohol. The enzyme acetaldehyde dehydrogenase converts acetaldehyde (a toxic substance) into acetic acid. This is important as a deficiency in this type of enzyme is associated with an increased risk of esophageal cancer in those who consume alcohol. The Vox video below explains further.

While this area hasn’t been extensively investigated archaeologically, it has been postulated that the reason we see higher rates of Alcohol Flush Reaction within Asian populations is a result of differences in cultural adaptation to water purification. Amongst European populations, it was commonplace to add alcohol to water in order to kill bacteria and avoid contraction of waterborne diseases, such as the case of Victorian London during the time of cholera.

Popular science writer Steven Johnson of Columbia and Brown Universities argues that living in higher density areas as opposed to rural settlements increases the demand for alcohol consumption in order to mitigate the risk of consuming polluted water. In turn, the act of consuming alcohol as a social norm to prevent illness leads to a selection pressure that favours genotypes which produce higher quantities of dehydrogenases (the types of enzymes that are seen in deficient quantities amongst Asian populations).

Interestingly, there is archaeological and DNA evidence to show that there was a significant increase in the frequency of the ADH1B allele in East Asian populations native to the Yangzi basin following the domestication of rice in around 10,000 – 7,000 years ago. The results from this study indicate that the increases in such gene expression is directly linked to the adoption of rice agriculture which varied from region to region with individuals from Tibet showing little to no expression of the gene.

Ultimately, the types of food and drink we can comfortably consume are a result of our own unique and individual evolution and genetic heritage which has been heavily influenced by our ancestors own lifestyle choices and culture. While the role of ‘evolution’ in dietary choices is important, we need to examine it within the context of our own more recent evolutionary history.

References

Bittman, M. (2016). Why Europeans Drank Beer and Asians Drank Tea. [online] Diner’s Journal Blog. Available at: http://dinersjournal.blogs.nytimes.com/2008/07/11/why-europeans-drank-beer-and-asians-drank-tea/?_r=0 [Accessed 21 Mar. 2016].

Blogs.crikey.com.au. (2016). London in the time of cholera –. [online] Available at: http://blogs.crikey.com.au/theurbanist/2010/06/24/london-inthe-time-of-cholera/ [Accessed 21 Mar. 2016].

Dudley, R. 2014. The drunken monkey: Why We Drink and Abuse Alcohol. University of California Press.

Li, H., Mukherjee, N., Soundararajan, U., Tárnok, Z., Barta, C., Khaliq, S., Mohyuddin, A., Kajuna, S., Mehdi, S., Kidd, J. and Kidd, K. (2007).

Geographically Separate Increases in the Frequency of the Derived ADH1B*47His Allele in Eastern and Western Asia. The American Journal of Human Genetics, 81(4), pp.842-846.

Peng, Y., Shi, H., Qi, X., Xiao, C., Zhong, H., Ma, R. and Su, B. (2010). The ADH1B Arg47His polymorphism in East Asian populations and expansion of rice domestication in history. BMC Evol Biol, 10(1), p.15.

Was early man pushing cars or running marathons?

There is no denying that physical activity is vital to good health, but just what did our Paleo ancestors do for exercise? It may have been strenuous, but how can this activity be compared to our modern lives?

In BBC Two’s ‘Eat to Live Forever‘ Giles Coren attended ‘Primal Con’ run by Mark Sisson of Mark’s Daily Apple mentioned in an earlier post on this blog.

Eat to Live Forever with Giles Coren by Catadecal

During the convention, Coren joins in on paleo style exercise which involved pushing a car and ‘the sledgehammer workout‘. Where did a creative interpretation of Paleolithic activities arise from? Other online self-proclaimed fitness gurus have developed numerous ‘systems’of exercise that our bodies were ‘designed’ or ‘programmed’ to do. These include MovNat by Erwan Le Corre, Primal Fitness by Greg Hetherington, and the Primal Blueprint by Mark Sisson to name a few.

All of these programmes differ from each other to a certain degree but are unified in promoting largely bodyweight only exercise, sprinting, interval training, and some form of lifting which, supposedly, is akin to the types of activities early man would have performed. Interval training is promoted as part of a ‘paleo’ lifestyle, similar to our ancestors having to run intensely for short periods of time to escape from predators and to hunt effectively.

Physiological studies into the effectiveness of interval training compared with traditional long distance endurance cardio training have produced some very impressive results including increased resting metabolic rate for at least 24 hours post training and increased insulin sensitivity of up to 28% in males. The degree to which participants benefitted from HIIT however, was affected by their individual genetic makeup and therefore, we must consider the role of genetic variability in our approach to exercise, and possibly, within the wider spectrum of diet. However, whether or not high-intensity interval training style activity actually occurred during the Paleolithic is debatable, and it is perhaps misleading to use an evolutionary basis for promoting a certain type of exercise.

Paleoanthropological perspectives on running

As mentioned in an earlier post, Harvard University paleoanthropologist Daniel Lieberman argues that humans were evolved to run long distances. According to Lieberman, humans ran long distances in the Savannah to scare large animals (ungulates) into sprinting. While these ungulates were good at running quickly for a short period of time, they would eventually overheat and experience exhaustion. Hunter-gatherers were, subsequently, able to successfully hunt and access meat by practicing this technique. This would contradict the view that humans alternated between short and long rest and activity periods during hunting. He argues that evidence for this is present in our own anatomy as we are biomechanically optimised to run barefoot through our shorter and easy to stabilise toes, the size of our glute muscles, and our achillies tendons that allow us to access energy at the appropriate time when we run. Our ancestors may have lead very active physical lives but that doesn’t mean we should all participate in intense physical activities. Pushing a car or running for miles is not for everyone. We need to consider what would be sensible and safe for our modern lifestyles and individual levels of fitness.

References

Bramble, D.M., Lieberman, D.E. 2004. Endurance running and the evolution of Homo. Nature.

King, J.W. 2001. A Comparison of the Effects of Interval Training vs. Continuous Training on Weight Loss and Body Composition in Obese Pre-Menopausal Women. Unpublished PhD Thesis. East Tennessee State University.

Metcalfe, R.S., Babraj, J.A. Fawkner, S.G., Vollaard, N.B.J. 2011. Towards the minimal amount of exercise for improving metabolic health: beneficial effects of reduced-exertion high-intensity interval training. European Journal of Applied Physiology.

Raw Veganism and the Hominid Diet – is there a case for cooked food?

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Image by: voyagevixen2

There are any number of modern commercial diets, each promoting very particular approach to the way we should eat. But which diet makes sense?

Consider the merits of a diet that prefers raw fruit over cooked food. Would archaeological evidence support such a diet?

Some wellness experts argue that humans were evolved to live almost entirely on raw fruits and vegetables. One controversial health blogger (with over half a million subscribers) in favour of this diet is Leanne Ratcliffe – otherwise known as Freelee the Banana Girl.

Speaking to the Daily Mail, Ratcliffe claims that consuming a high carbohydrate, low-fat vegan diet consisting of ‘mono meals’ is in keeping with how humans were evolved to eat. According to Ratcliffe, such a diet is supposedly optimised for our digestive system:

Most of the body’s energy goes towards digesting food so when we eat meals that contain several different foods the body has to work harder not only to process the complicated combination but to extract the nutrition it needs.

…Just one type of digestive enzyme is needed to process the meal. If you look to nature you will see that animals in the wild always eat mono meals and do not suffer the same digestive problems or weighty issues as we humans commonly do.

…Imagine our ‘tribe’ came to an abundant mango tree in nature, we would have happily filled our bellies with only mangoes and then moved on to the next location. This is what I largely replicate on the raw till four lifestyle.

Take a look at the ‘Raw Till 4’ Food Pyramid:

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Photo Credit: Freelee the Banana Girl via the Daily Mail Online

The food pyramid that doesn’t add up

The problem with this food pyramid is that it emphasises the consumption of raw fruit while cooked vegetables make up the smallest meal of the day. The consumption of raw fruits and vegetables in nature is often seen in animals with smaller brain sizes and larger digestive systems, such as cows and gorillas. The importance of cooked vegetables is underestimated in human evolution; indeed, cooked vegetables circumvent the need for complex digestive systems and free up more energy to grow larger brains. This is archaeologically reflected in hominid fossil teeth and jaw shape. The more primitive species of humans possess more robust features, such as large canines and chewing apparatus. Archaeological evidence for cooking and hearth use is indicated as early as the Acheulian period 790,000 years ago at the site of Gesher Benot Ya’aqov in Israel where the charred remains of several edible plant species were found including olive, wild barley, and wild grape.

Furthermore, physical anthropologist Katherine Milton argues that meat was eaten by hominids as a means of providing essential amino acids and nutrients. This left more stomach space for the selection of higher quality and more easily digested plant foods. Studies on primate metabolism have indicated that there is an upper limit to how much raw food can be eaten over a day and a trade-off between access to calories and ability to digest such foods.

While raw veganism might superficially appear to be a ‘natural’ diet for humans insofar that it is rooted in fruits and vegetables, it is not reflective of the actual hominid diet that allowed our brains to reach the cranial sizes we see today.

References:

Conroy, G.C., 2005. The Debate Over “Man the Hunter”. In: Reconstructing Human Origins: A Modern Synthesis. New York: W.W. Norton

Evolved to exercise – but how?

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Image by Andy Wright

Obesity is now a global problem

According to the World Health Organisation, the global obesity rate has more than doubled since 1980 and 1.9 billion adults were overweight in 2014 while over 600 million of these were obese. Sedentary modern lifestyles present a unique problem for the human metabolism. We have evolved to be attracted to high-energy foods and sugars. During the Paleolithic period, sugars and fats were beneficial when we needed to run and hunt; calories were naturally burnt off throughout the day. However, switch the Savannah for the office and the scenario changes.

Our brains are hardwired to crave foods that will provide us with high energy but, it is energy we no longer need for the types of activities we do. Furthermore, our bodies are evolved to move, and bearing body weight is essential for the retention of bone density. In fact, after 36 weeks of bedrest, we lose between 24-40% bone density in the heel (Bortz, 1984).

Run versus sprint: suggestions from archaeology that might save us

Prominent Paleoanthropologist Daniel Lieberman argues that humans were evolved to run extremely long distances. His studies on the biomechanics of the human foot indicate that we are morphologically adapted to long distance running. In contrast, Mark Sisson of Mark’s Daily Apple argues for high-intensity interval training through his Primal Blueprint Workout Planwhich supposedly can ‘hack’ our evolutionary biology to attain the best physical fitness possible. His suggestions stipulate ‘running really fast once in a while’ on the basis that our ancestors existed in a world of infinite danger that required us to sprint after and away from predators. He argues that this constant environmental pressure resulted in a gene expression within fast twitch muscle that meant we were evolved to sprint faster. In the most basic of terms: survival of the fittest.

However, these arguments rely heavily on theoretical knowledge. We cannot go back in time and watch our hominid ancestors carry out their day to day activities, but we do know that the paleo-environment was unforgiving and it would have required enormous effort just to survive and reproduce successfully. We can look to modern day hunter-gatherer groups and their activity patterns as a means of ethnographic analogy.

References

Bortz, W.M., 1984. The disuse syndrome. Western Journal of Medicine.

The use of GIS and Satellite Imaging Technology (and others) in Archaeology

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Hieroglyphs, Temple of Kom Ombo. With thanks to Saf’ via Creative Commons

Now for those of you who watch Time Team, you’re all probably pretty familiar with the fantastic digital imagery they conjure up to recreate what a site looked like in its former glory! We also are introduced to some of the methods archaeologists use in finding where to dig – ‘GeoPhys’ as Tony Robinson affectionally puts it but what about finding sites of interest in general? What are some of the main techniques that archaeologists use to determine the potential of a particular site?

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Satellite image of the Ram Desert, Jordan with thanks to PlanetObserver via Creative Commons

1) Remote Sensing

Satellite photographs of the potential area are examined for clues in the landscape topography that might indicate previous settlement and archaeological structures. Geographic Information Systems (GIS) can be particularly useful in conjunction with satellite imaging as they are a powerful database which can store multiple layers of data against individual grid references on a map. They can show details such as topography, geology, vegetation and archaeological structures.

2) Surface Surveys

Field walking and surveying can help archaeologists find traces of unrecorded sites through evidence such as scatters of building rubble or artefacts. Differences in vegetation may also be an indicator of previous human activity. When studying Mesolithic and Neolithic Britain, scatters of flint and animal bone are usually the only traces of human activity visible. Studying nomadic societies requires meticulous plotting of scatters. Micro-contour surveys of the topography can also be useful and these involve surveying tools to create a picture of variations in height and levels. These types of surveys can reveal hidden features that are not detectable upon first sight.

3) Magnetometer Surveying

The cool looking one! Local magnetic distortions can be caused by previous human activity such as top soil containing haematite iron oxide (in which some of its crystal forms are magnetic). A second kind of distortion is that of the topsoil having been subjected to high levels of heat. Today hand-held fluxgate gradiometers enable this type of surveying technique to be efficient and accurate in detecting magnetic anomalies. Although this type of technology has been well developed today, trouble can occur when the soil contains other metal objects such as iron nails, pipes, and wire fences (and even piercings on the archaeologist him or herself!)

4) Caesium Vapour Magnetometers

CV magnetometers are much more sensitive than conventional magnetometers. They work by using several machines close together on a wooden handcart. Caesium Vapour is pumped and the magnetometer takes rapid measurements around 25 cm intervals. The CV is alkali and therefore sensitive to minute variations in magnetism so it is capable of detecting and defining edges of buried features formed by traces of magnetite! CV magnetometers are less susceptible to interference from background ‘noise’ as such but at £40,000 a pop, the technique is much more dear than the classic!

5) Cropmarks

Unsurprisingly, or maybe surprisingly, the ripening and growth rate of crops can be an indicator of buried archeological features under a field. A buried ditch with infills of humus and topsoil often holds moisture and will create a green line – a ‘positive’ cropmark visible from the air. When plants are buried over a  wall a ‘negative’ cropmark (stunted, yellowish growth line) will show. Repeatedly flying over these areas over time can pick up features. This technique works most effectively on quick draining soils (i.e. river gravels) and less so on poorer draining (retain more moisture) areas such as clay soils and areas of deeper topsoil. The type of crop being observed also affects the techniques success – cereal crops such as barley and wheat show up best while peas and beans less so (especially when covered by irrigation or fertiliser). Additionally, geological features such as periglacial cracks and modern field drainage and underground pipelines have to be taken into consideration when interpreting aerial images as these can also produce similar results. Cropmarks are particularly important in uncovering late Neolithic to early medieval period sites.

6) The coolest and most advanced…

I recently saw this on ‘Egypt’s Lost Cities’ a documentary by Dr. Sarah Parcak (A ‘space archaeologist!’) on Yesterday TV. Parcak uses ‘space archaeology’. What is ‘Space Archaeology’ you ask? It uses satellite imaging to show subtle changes at pixel level. The human eye can only see part of the light spectrum while space cameras on satellites have a higher complexity of resolution. Images can also be altered using advanced computer programmes to accentuate certain features on the satellite image. Space archaeology has led to the uncovering of 44 previously unidentified sites including an Egyptian Harem believed to have played a prolific part in King Tutankhamun’s childhood. It has been estimated that less than 1% of Egypt’s ancient wonders have been discovered but now thanks to satellite imagery the impossible is about to happen.

Sources:

The Archaeology Coursebook: An Introduction to Themes, Sites, Methods and Skills
Jim Grant, Sam Gorin, Neil Fleming

Yesterday TV

National Geographic 

Uncovering the Tiwanaku: Lost Kingdoms of South America, Dr. Jago Cooper

I haven’t had much exposure to South American archaeology but I just caught up with a great documentary on the Tiwanaku people of Bolivia. A group that grew significantly in power between circa AD 300 and AD 1000. Dr. Cooper’s documentary explored several themes surrounding their rise and subsequent fall such as how the Tiwanaku transported the large boulders that built their famed architecture, how, surprisingly, ‘Chicha’ beer was an integral part of building social and labour communities and the use of hallucinogenic drugs and snuff were used in religious ceremonies!

Verzonken Temple, Tiwanaku, Bolivia

Tiwanaku, Bolivia, with thanks to Benjamin Dumas via Creative Commons

The Tiwanaku are particularly famed for their awe-inspiring structures such as Sunken Temple near the South shore of Lake Titicaca and Kalasasaya which are both composed of large stone boulders and used complex carving skills to be produced. Dr. Cooper investigated how such large stone boulders were transported across Lake Titicaca. The answer?

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Boat made from Totora Reeds, with thanks to terrydu via Creative Commons

Totora reeds! While there was no access to wood near Lake Titicaca making wooden boats unviable, the reeds on the banks of the lake meant that the Tiwanakus braided the reeds to create solid floating boat structures such as the one shown in the above picture. The reeds themselves have a fibrous membrane within them making them stronger and more resilient for use on water. In 2010, experimental archaeologists tested the theory by building a giant one of these – they managed to sail a 9 tonne rock across the lake, not bad eh for a few woven reeds?

The Tiwanaku practiced a religion that centred itself around worship of the natural environment. All monuments built by them are not in honour of a king or monarchy (it is suspected that there was no monarchy as it was a universally labour intensive society) but rather in the honour of the mountains that watered their crops through meltwater from snow. The Tiwanaku had priests who would hold ceremonies in which they would drink beer in ‘keros’ highly decorated ceremonial vessels and take hallucinogens (powdered from seeds of the Vilca tree).

Tiwanaku Benjamin Dumas

Statue showing use of a snuffbox and beer drinking vessel, with thanks to Benjamin Dumas via Creative Commons

A distinctive feature of Tiwanaku skulls is that they underwent a form of deformation – a cultural practice used to differentiate themselves from others and to be able to identify themselves as a cultural elite. In order to obtain said skull shape, shaping began in infancy when the child’s head was put between two boards and bound.

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skull deformation image by 10b travelling via Creative Commons