«By Nathan B. Goodale A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY WASHINGTON STATE ...»
By relating recent advances in understanding how fertility is affected by the nutrients in our foods to the origin of a Neolithic demographic transition we can begin to understand why this demographic transition occurred in tandem with intensified food production. Here, and in following chapters, it will become apparent that the foods our ancestors ate and started to cultivate not only had the properties of being predictable and abundant, but the wild and early domesticated forms had the nutrient content ideal for increasing and/or sustaining fertility.
Examination of staple resources associated with all the areas where agriculture developed independently and where an NDT occurred indicates these resources were not only predictable and abundant, but share the qualities Chavarro and colleagues (2008) demonstrate increase fertility. These resources include, slowly digested carbohydrates such as rice in China, wild emmer wheat (and probably barley) in the Near East, and maize in Mesoamerica. As well, salmon is associated with a major demographic transition in the Pacific Northwest of North America (Goodale et al.
2004, 2008a). Finally, the use of goat dairy farming, and probably cattle later in the Near East, added the whole-fat dairy products that Chavarro et al. (2008) indicate could have a significant impact on fertility.
Diet and Fertility in the Southern Levant It is plausible that subtle changes in the structure of wild plants brought on by human selection produced enough variation in the nutrition of plants to be at least
Of course, other human behavioral elements also played critical roles in the NDT, including technological developments and flexible parenting to invest in more children that ultimately enabled population to grow.
Contrary to assumptions of poor health during the entirety of the NDT (Cohen 1977b; Cohen and Armelagos 1984; Starling and Stock 2007; Steckel et al. 2002;
Larsen 2006), the initial cultivation and increased use of wild emmer wheat and legumes in the southern Levant would have afforded good health and fertility to late Natufian and early Neolithic populations. Moreover, the change from a predominately meat-driven subsistence economy of hunting gazelle to focusing on fewer and smaller juveniles (Techernov 1994) with an increase reliance on plant protein modified the type of proteins people were ingesting. This generalized dietary shift from one that incorporated large amounts of animal protein (Munro 2004; Techernov 1994) (which was not very good for fertility) to one that incorporated higher amounts of still-wild plant protein, would have increased fertility probably some time around the start of the Pre-Pottery Neolithic. Importantly, however, this new diet was in detriment to the intake of iron, zinc, or other nutrients found in high quantities in wild cereals (wheat and probably to a lesser but still important extent, barley). Additionally, by the Middle to Late Neolithic transition, sheep and goat domestication likely provided high-fat content dairy products further complementing the fertility diet. In other words, the geographic area of the southern Levant contained all of the types of foods required by the fertility diet and once intensive storage technology was invented (as
Storage Technology and Fertility Food storage may be defined as a technique which allows the preservation of food for significantly longer periods of time than the harvest season. However, not all storage strategies are the same. We might define abated storage techniques, where only minimal amounts of foods are kept for longer periods of time than end of the harvest season (Testart 1982). A different type of storage might be defined as intensive storage techniques, where significant portions of foods are kept for longer than just when resources are available (Testart 1982). In this section I address the general connection that has been suggested by Alan Testart (1982) between these storage technologies and the rise of civilization, yet my focus is on the NDT.
Through particular attention on the archaeological evidence for the development of storage technology in the Near East, I examine new significant studies in experimental archaeology concerning storage technology, and its importance to the fertility diet.
Storage and the NDT The ability of people to store foods has been discussed in a variety of ways including as a very important aspect which provides the foundation for civilization (Testart 1982), or just one of several variables of which may not be “its (civilization)
comment reviewers presented a Current Anthropology discussion piece in which the importance of intensive food storage economies was highlighted and correlated to mobile/sedentary population densities and social organization. Testart’s position was very clear on the issue: intensive storage is a crucial aspect to the rise of civilization and the foundations of complex social organization. He argued that “sedentism triggers population increase, and intensive food storage enables the population to stabilize at a higher level of density” (Testart 1982:525), and further suggests that “all the material, social, ideological, or political prerequisites for the emergence of social inequalities seem to be present in societies with a storing economy” (Testart 1982:528).
It is pretty obvious that Testart puts a high level of importance on storage practices as basically the foundation of modern civilization. As one would expect with these lofty expectations based on a single variable; several of the discussants on the topic flatly refused to lend this much significance to the development of storage technology (Forbis 1982; Ingold 1982). Even so, the basis to my argument tends to agree with some of Testart’s assertions by placing a high importance on storage technology for the origins of agriculture and the NDT. The difference is in how storage relates to the bigger picture of the foundations of social inequality, which I would argue is multi-faceted.
In the Near East we see potential examples of both abated and intensive storing economies. Although controversial, abated storing techniques might be found during the Natufian tradition as evidenced by rare small pits and the suggested use of baskets above ground (Bar-Yosef 1998). However, recent arguments suggest that the Natufians were not storing food at all (Boyd 2006). On the other hand, intensive storing techniques appear to be invented in the Early Neolithic during the Pre-Pottery Neolithic A (11,700-10,500 cal BP) (Kuijt 2008a; Kuijt and Finlayson n.d.).
Conclusive evidence appears from the site of Dhra’ (Finlayson et al.2003; Kuijt and Finlayson n.d.), where at least four granary storage structures were recovered with what appears to be a dedicated use of food storage (namely wild cereals). Other sites in the region contain evidence of storage technology, including Netiv Hagdud (BarYosef and Gopher 1997); Wadi Faynan 16 (Finlayson and Mithen 2007) and Jericho (Kuijt 2008a). A detailed examination of when and where storage technology is first evident in the prehistory of the southern Levant is discussed in Chapter Five.
Experimental Studies in Storage Technology Surprisingly little experimental work has been directed to the appropriate climate for storing food (in terms of hot/cold or wet/dry conditions) and the duration of the storability of different types of food. The factors that would influence how long foods can be stored could include, but may not be restricted to, types of food being stored, the climate conditions of the area where the food is being stored, the
was stored (dried, smoked, etc.). In fact, I was unable to find one source in the published literature that experimentally treated these questions. There is one unpublished study that has addressed this specific problem and although it is preliminary, it correlates very strongly with what we see in the archaeological record (Ortmann n.d.).
Specifically, Ortmann (n.d.) organized her study around an experimental program to determine how long cereal foods will store in above- and below-ground storage facilities in hot and dry climates. Results indicate that regardless of whether the storage facility is above or below ground or in a hot or dry environment, cereal foods can be preserved at an edible state for ca. 13 months on average (Ortmann n.d.).
If this were the case, and storage technology also functioned to prevent significant loss due to rodent infestation, foods would become available well beyond the harvest season, thus providing a highly stabilized diet of foods associated with higher fertility.
Results of Ortmann’s (n.d) study demonstrate that once storage techniques became regularly practiced, cereal grains had the potential of being available yearround. Off-season availability of grain resources would have provided security from shortfalls of other harvested resources (Bettinger 2006) and long-term interaction of early plant domesticates (nutrient rich) with human biology. Significant to the early phase of the NDT, this aspect of long-term interaction with initially wild varieties of cereal grains could have enhanced fertility and general health.
for understanding how the prehistoric nutrition shift could have affected fertility and total fertility rates, the question still remains as to what social mechanisms were in place to influence women to bear, and parents to invest in, more children. In other words, what is the difference between forager and hunter-gatherer socioeconomic systems that may encourage higher birth rates and potentially why population regulation mechanisms such as infanticide or birth spacing were not a significant factors, further allowing population to increase during the NDT?
Sedentism, Exercise, and Fertility A shifting food economy to greater intensification and the development of long-term storage technology led to the availability of sufficient natural resources year-round and the change from more mobile to sedentary lifestyle. While still debated (Handwerker 1983; Sattenspiel and Harpending 1983), it is commonly suggested that population growth increased substantially among early agrarian societies due to semi-permanent settlement or full-time sedentism (Johnson and Earle 1987; Hassan 1981). There are ethnographic correlates around the world where hunting and gathering groups have smaller population densities than settled forager/agricultural groups. But why is this the case?
One explanation that has been cited for increased fertility among sedentary groups is the degree to which women participate in active exercise. Based on modern studies (Sanborn et al. 1982), excessive, strenuous, and long-duration exercise can
cycles. The logic follows that females, who participate in less excessive physical activity, but sufficient moderate exercise, will have more regular menstruation (RichEdwards et al. 2002). At the same time, obesity can cause problems with fertility (Green et al. 1986; Morris et al. 2006), and research suggests that women who correct being overweight through moderate exercise can greatly increase their chance of getting pregnant (Green et al. 1986; Rich-Edwards et al. 2002).
In the past couple of decades, research investigating a possible connection between excessive physical exercise and infertility has been based on the examination of female athletes, especially those undergoing professional training. Results indicate an overall decrease in fertility among these women, but not all female professional athletes have reduced fertility. This poses the concern that the relationship between exercise and fertility is much more complex than can be summed up in a simple statement (Morris et al. 2006; Rich-Edwards et al. 2002), and the correlations between these two variables have not been proven positive (Morris et al. 2006).
Morris et al. (2006) recently presented a large case study of 2,232 couples undergoing in vitro fertility (IVF) treatment for infertility. The couples were questioned about different aspects of their lives, tested for ovulatory cycles, and classified into groups based on exercise type and duration. Three main conclusions demonstrated the roles of exercise and fertility. First, women who exercised moderately, defined as 1-3 hours a week, for either one to nine years or 10 to 30 years before the study, showed similar positive responses in fertility and IVF. Women who
per week, for one to nine years before the study, were as much as three times as likely to “experience cycle cancellation” still birth, or “implantation failure” (Morris et al.
2006:938). However, the really interesting point is that women who engage in intensive exercise for more than four hours per week but longer than 10 years before the study showed positive correlations in IVF treatment and fertility. Morris et al.
(2006:946) suggest that there may be an exercise threshold incorporating a time period where the body acclimates to intense exercise that may be linked to a hormonal output adjustment. This relationship between exercise intensity and duration may be modeled similar to Figure 4.3.
The exercise threshold model suggested by Morris et al. (2006).
What are the implications of this with our question of fertility correlates and the transition to sedentism? If we compare the life ways of pre-industrial societies