The implications of farming for people
Whyfarm?
As has been discussed above, one question that continues to be debated is why people started farming in the post-Glacial early Holocene, or in the first 5,000 years of the last 10,000.
This occurred independently in Africa, Asia, the western Pacific, and the Americas.[160] A number of possible reasons have been suggested: the population increased so more food was needed to feed that growing population (or did agriculture develop to then allow the population to grow?), climate changed and wild animal and plant resources became scarcer, or people essentially wanted a more reliable source of food. However, as is well known, people even today do not necessarily only have agriculture to rely on for their subsistence, as they may also practise pastoralism, or hunt and forage for wild resources, especially in season. The transition to agriculture in the past may also have been over a long time period, with no single subsistence activity predominant, and some people may have preferred to have different subsistence strategies working alongside each other, especially when circumstances made this logical (e.g. extreme weather conditions, harvest failures, etc.). This is the situation in the Levant where the Neolithic Revolution was clearly complex and long term.[161]Advances in methods and understanding the agricultural transition in bioarchaeology
Advances in understanding the nature of the agricultural transition and its impact on humans have particularly been seen recently in genetic studies, for example how plants and animals have evolved,[162] and how human genes have adapted and changed. An example of the latter can be seen in lactase. The production of the enzyme lactase in the human body is needed for a person to be able to digest lactose (milk sugar), and therefore with the domestication of animals and the consumption of dairy products this becomes important (lactase persistence).
A single nucleotide polymorphism (SNP) in the MCM6 gene encoding lactase (13,910*T) is associated with the ability to digest milk in European populations. Lactase persistence has an approximately 95 per cent prevalence in Europe, but in other areas of the world, south and east of Europe, this frequency declines.[163] Burger et al. have identified lactase- persistent associated genotypes in eight Neolithic (5800-5000 bce) skeletons and one Mesolithic (2267 ± 116 cal bce) skeleton from central, northeastern, and southeastern Europe, but the allele most commonly associated with lactase persistence in Europeans was not found.[164] This was interpreted as evidence that it was rare in early European farmers. This type of research shows how advanced methods of analysis can now tell us much more about how people adapted to making a living with agriculture.Health, diet, and agriculture
Until more sophisticated analytical methods developed, the key research on the impact of farming on diet and health was the pioneering work of Cohen and Armelagos in which many studies of demography and health in skeletons of people from around the world who had made the transition to farming were presented.[165] The work was the outcome of a conference held in 1982 and was a landmark ‘event' that has precipitated an abundance of studies since then on health (and diet) at the agricultural transition. The goal of the volume was to compare studies of the economic transition from hunting and gathering to farming. What was consistent was a decline in quality of life following the adoption of farming. Likewise, many of the studies in Cohen and Crane-Kramer document declines in health, this volume showing a similar picture but this time more globally distributed.[166] However, the picture is complex and is not consistent across time or space. Cohen and Crane-Kramer conclude their volume by saying that, ‘Overall, evidence of health decline through time is far more common than evidence of stability or improvement' but that ‘nothing more than broad generalisations should be expected'.[167] Regional differences will of course reflect a variety of factors, including the location of sites studied (latitude/longitude) and social, cultural, political, and economic factors.
‘Living environment' and farming: how does life change?
Why might a decline in health be caused by growing food and keeping animals? Fundamental to this question is that the ‘Palaeolithic diet' was abandoned with farming, even though the hunter-gatherer lifestyle was, and is, inherent in how the human body has evolved.[168] In effect, a mismatch between human evolution and diet has developed, and remains with us today as we practise an even more sedentary lifestyle and eat against the evolutionary grain.[169] In addition to this, as Cohen suggests, ‘human activities can create disease or increase the risk of illness just as surely as medical science reduces the risk'.[170] Nevertheless, people can adapt to changes over generations and longer periods of time, and eventually develop tolerance (or not) and increased metabolic efficiency for staple foods on which they are reliant (see above concerning lactose intolerance). Another example of intolerance to food can be illustrated with regard to gluten, whereby the inability to digest gluten in cereals, and associated coeliac disease, have occurred as farming has developed.[171] The HLA B8 DR3 gene has been associated with gluten intolerance, thereby showing it to be a genetic disorder.
It is perhaps rather obvious to say that it is very difficult to grow food and keep domesticated animals while ‘on the move' so, in the past, permanent housing and settlements became the norm with agriculture, leading to problems of refuse disposal and vermin, contamination of the water supply, poor hygiene and sanitation levels, potential harvest failure and soil exhaustion, and a decline in the variety, quantity, and quality of foodstuffs available. While population density increased, the impact of these changes on everyday life led to consequent increases in infectious disease loads, zoonoses, dental disease, and nutritional deficiency diseases; social inequality also developed. However, there were ways of mitigating the disadvantages farming communities experienced, such as protecting and manipulating crops and storing food.