«By Nathan B. Goodale A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY WASHINGTON STATE ...»
Using ethnographic data on TFR and subsistence modes from 56 cultures around the world, Sellen and Mace (1997:884) provide a number of interesting conclusions regarding how people integrate different subsistence modes, and they also show how subsistence mode correlates with TFR. First, among these cultures, hunting and gathering subsistence strategies correlate positively, indicating that they are practiced together. However, there is no correlation between hunting and gathering and increased TFR. Second, among the sampled cultures, hunting and agriculture negatively correlate suggesting that these modes “substituted for each other across cultures” (Sellen and Mace 1997:884). Third, the addition of and increased reliance on domesticated animals decreased the need for all other modes of subsistence (hunting, gathering, and agriculture). Fourth, dependence on agriculture was the only variable positively correlated with increased TFR. This suggests that dependence on agriculture is possibly linked to the Neolithic demographic transition,
that attempts to cope with the time-dynamics present in the archaeological record.
Health and Nutrition Associated with both fertility (birth) and longevity (death), health is a frequent topic associated with the transition to food production (Bocquet-Appel et al. 2008;
Cohen 1977b; Cohen and Armelagos 1984; Hassan 1981; Hassan and Sengal 1973).
Often discussed in a negative manner, the discussion of health during the NDT usually centers on decreased health due to increased carbohydrate intake (Cohen 1977b; Cohen and Armelagos 1984; Starling and Stock 2007; Steckel et al. 2002;
Yesner 1980; Yudkin 1969). But it has never been entirely clear why a marked decrease in health would be linked to a significant increase in population.
Investigating Health Building upon the idea of a two-phase aspect to the NDT discussed in Chapter Three, Bocquet-Appel et al. (2008) have provided a detailed model of health change during the second phase of the transition in the American Southwest. Within this discussion they examine the proportions of caries (tooth decay), porotic hyperostosis (osteoporosis), cribra orbitalia (pores in bone indicative of anemia), and sexual dimorphism found in human remains spanning the transition (Figure 4.2).
Interestingly, the results indicate that porotic hyperostosis and cribra orbitalia, both results of heightened red blood cell counts coinciding with chronic iron-deficiency
In light of this observation, the question becomes, why do these health risks occur so late in the sequence?
Signatures of health in relationship to the transition of agriculture in the American Southwest where a = frequency of caries, b = porotic hyperostosis and c = cribra orbitalia. Redrawn from Bocquet-Appel et al. (2008:Figure 7).
For the southern Levant, Eshed et al. (2006) indicate differences in nutrition for Natufian and Neolithic populations through examination of dental attrition versus ecological zones, but they provide no real direct evidence for a shift in health. Their study focuses on dental attrition (wear on the enamel), caries, calculus (plaque), antemortem tooth loss, periapical lesions (defense of microbial infection of the root canal), and periodontal disease. The results indicate that dental attrition is significantly higher in Natufian and Early Neolithic populations than in Late
consumption of coarser foods. On the other hand, dental caries, antemortem tooth loss, and periapical lesions, were all similar for both the Natufian and the early and late Neolithic. One of the most substantial distinguishing factors differentiating the Natufian and early Neolithic populations from the late Neolithic populations is the amount of calculus present on the teeth. Late Neolithic populations had far greater amounts of calculus than all other samples, suggesting a higher rate of dependence on agricultural products and increased carbohydrate intake (Eshed et al. 2006:155).
However, other components besides diet can influence the amount of calculus present on teeth such as hygiene and the use of teeth for other purposes than to eat (such as tools).
Currently there is little osteological data available in the Near East regarding the health of people living in the Epipaleolithic and Neolithic periods. Current data indicate, based on very minimal research, that good health was maintained throughout the Pre-Pottery Neolithic (Smith et al. 1984:129), suggesting that either the two-phase definition of the NDT (Bocquet-Appel et al. 2008) may not always be apparent or that this early work lacked samples from the latest Neolithic periods (such as the PrePottery Neolithic C or the Pottery Neolithic discussed in Chapter Five). Without sufficient osteological data, for the time being we must turn to other measures of health, namely the known nutritional qualities of the foods that people were eating, to gain some measure of health during this time period. However, we have to also
as bad off, or worse off, than people with access to plenty of bad-quality food.
Quantity vs. Quality In the archaeological literature, health and fertility are usually closely related to food quantity (Jackes and Meiklejohn 2008; Kramer and Boone 2002) but much less effort has been expended measuring quality, or the nutritional content of foods.
When quality is discussed in terms of the Neolithic diet, it is usually briefly addressed or in a qualitative manner, citing too many carbohydrates and not enough protein (Cohen 1977b; Cohen and Armelagos 1984; Starling and Stock 2007; Steckel et al.
2002; Yesner 1980; Yudkin 1969). While I agree that the late Neolithic diet in general may have been characterized as high in carbohydrates, this is less likely to be the case for the Early Neolithic (Eshed et al. 2006; Smith et al. 1984:129). In actuality, the NDT as a long process of plant domestication where both the morphological and nutritional signature altered over time can offer insights as to why this demographic transition may have occurred.
Examining food to determine carrying capacity has ordinarily assumed that certain quantities of food constitute the key limiting factor (Cohen and Armelagos 1984; Roosevelt 1984:567). However, this relationship is somewhat uncertain and the concept of carrying capacity itself has been called into question as an over simplification of reality (Boone 2002), potentially best attributed to how difficult it is to provide an accurate estimation of carrying capacity for past environments.
without a detailed paleoclimatic record.
Contemporary studies suggest that wild forms of the foods we have in domesticated form today have very different nutritional profiles than did their ancestral wild forms (Chavarro et al. 2008). Domestication not only changed the morphology of the plants, but also their nutritional quality. Moreover, early discussions of Neolithic health did not benefit from the much more detailed information that we now have regarding the initial parts of the transition in the Near East and instead focused on characteristics of populations with full-scale agriculture diets. Cohen and Armelagos (1984:587) acknowledge this problem pointing out that most of the early studies were conducted on human remains recovered from contexts associated with full-scale agriculture during the late Neolithic.
Taking these nutritional components into consideration, as well as the evolutionary process of selection that have changed more that just the morphology of plants over the last 10,000 years, we essentially assume that hunting and gathering provides a diet that more adequately balanced protein, carbohydrates and other nutrients. Of course, this is an oversimplification in that the foods associated with the NDT are exactly those which modern physicians recommend for women who want to get pregnant; these foods could in themselves have increased fertility rates in early Neolithic populations (Chavarro et al. 2008). Moreover, the invention of storage technology (and intensively storing foods as defined below) provided a more stable diet where foods were potentially available on a longer than seasonal basis.
While recent research has demonstrated that the Neolithic demographic transition was a real phenomenon, we lack a detailed discussion as to why there was an increase in fertility at the beginning of the transition. One potential explanation is that there is good reproductive health (Chavarro et al. 2008), and a growing literature on the foods that can lead to increased fertility in women, and to a lesser extent in men, corroborate this assertion (Chavarro et al. 2004; 2007a, b, 2008). This literature is especially important because the foods that people were eating dramatically changed, albeit gradually, through the transition to agriculture. While this body of literature is growing, there are still many questions regarding how the fertility diet (described below) could influence the large-scale demographic transition that people went through over the course of several thousand years in the southern Levant.
Nevertheless, new approaches to understanding the increase in fertility at the start of the NDT merits a discussion of those foods that help to increase fertility.
The following review is focused on recent publications of Chavarro et al.’s (2007a, b, 2008) findings from the Nurse’s Health Study that included a total of 289,700 participants. The size of this dataset no doubt lends credence to its findings.
While the results were obtained through the study of modern women and men, this is the best dataset we have to provide insight into what components of the prehistoric diet could have helped generate higher fertility rates and a subsequent NDT.
The diet that Chavarro et al. (2008) suggest to best promote fertility has an uncanny correlation with the foods that people had access to during the transition to agriculture in the southern Levant and for that matter, other locales where the NDT occurred. Based on abundant research, the fertility diet is suggested to be balanced, low in saturated fats, containing no trans-saturated fats, with low amounts of red meat (but enough maintain iron levels), a great deal of protein from plants as well as foods high in omega-3 oils, including some species of fish and whole wheat. Omega-3 fats are prevalent in some fish including wild and farmed salmon, Atlantic Mackerel, and sardines.
Dairy products are also suggested as one of the most important dietary staples for increased fertility, but only whole or high-fat dairy, as the process of making reduced-fat dairy products extracts estrogen and leaves testosterone and prolactin (both bad for fertility) (Chavarro 2008:112; Chavarro et al. 2007a). Interestingly, goat milk on average contains 1-2 more grams of fat on average per serving than cow milk, suggesting it may be even more beneficial to fertility.
Another interesting, recent development is the understanding of nutritional content in both wild versus domesticated wheat. Uauy and colleagues (2006) found that the modern domesticated wheat contains significantly (over 30 percent!) less protein, iron and zinc than its wild ancestors. In addition, wild emmer wheat (Triticum turgidum sp.) – the ancestor to one species of domesticated wheat (T.
turidum ssp. durum) – carries the NAC gene which “accelerates senescence and
2006:1298), increasing the amount of plant protein, iron, and zinc. In fact, it has been suggested that cloning the NAC gene found in wild emmer and breeding it into domesticated wheat, would significantly reduce nutritional deficiencies in developing countries. As discussed in Chapter Five, archaeological evidence indicates that emmer was one of the primary early pre-domesticates in the southern Levant.
Other differences between domesticated and wild wheat could have had important effects on fertility. Refining domesticated wheat has a major impact on the nutritional content by removing the majority of the bran and the germ. This process takes away 70 percent of the iron and 50 percent of the B vitamins that are very important for fertility (Chavarro et al. 2008:46, 2007). Additionally, refined wheat is much easier to digest than unrefined wheat, which gives a fast rush of sugars to the bloodstream. In contrast, unrefined wheat with bran and germ intact is digested much more slowly, yielding a steady increase in blood sugar and insulin while providing many more nutrients (Chavarro et al. 2008:46).
Within the digestive system then, easily digestible domesticated wheat provides “a roller-coaster ride” (Chavarro et al. 2008:47) relative to the slow and steady digestion of wild wheat. Because of this, domesticated and refined wheat often lead to health issues with weight gain and low fertility. Chavarro et al. (2008) demonstrate a very strong positive correlation between high ingestion rates for wild and minimally processed cereals grains and increased ability for women to get pregnant. They found that women with high glycemic loads, or those who eat a high
infertility. In contrast, women who ate slowly digested carbohydrates, such as rice and dark bread, increased their fertility substantially. Interestingly, Chavarro et al.
(2008) found that the amount of carbohydrates did not have an effect on fertility, whereas the type and quality of carbohydrates did have significant effects.
Consequently, the consistent ingestion of wild unrefined grains during the initial phases of the NDT provided through storage technology, could have been a significant factor increasing fertility.
While some of the suggestions for the fertility diet do not transfer directly to an early Neolithic diet, there are arguably striking similarities. The following is a summary of the dietary requirements suggested by Chavarro et al. (2008) for increased fertility in modern humans.
1. Increased slow carbohydrates, no highly refined ones.