Anthropology 275

Anthropology 275/710 - Fall 2002 Exercise for chapter 5

COMPARING NUTRITION IN PREHISTORIC HUNTER-GATHERERS AND FARMERS

The material in this exercise comes from a study by physical anthropologist Claire Cassidy, who compared evidence of nutritional health in the skeletal remains of two populations: agriculturalists who lived about 400 years ago in what is now eastern Kentucky, and hunter-gatherers who lived in western Kentucky about 5,000 years ago. Habitat variables (animals, plants, water, and climate) were very similar for both populations.

The basic research question was: Was the health and nutrition of farmers better than the health and nutrition of hunter-gatherers in prehistoric times?

One reason why this question is important is that anthropologists have assumed that people who grew their own food had stable supplies and even a surplus, whereas hunters were thought to have unpredictable resources. However, there is some evidence that drought, infestation of insects, and famine were all too frequent problems of agriculturalists. Ethnographies of some foraging groups, such as the San of the Kalahari and the Hadza of Tanzania, have shown ample food supplies and a healthful variety of seasonal foods.

Dietary patterns:
The hunter-gatherers had a high protein, low carbohydrate diet. They ate large quantities of river mussels and snails. They also ate deer, small mammals (e.g., squirrels, porcupine, raccoon, etc.), wild turkey and other birds, box turtle, and fish. Sometimes they ate dogs ceremonially, and they ate gathered wild plants such as wild grapes, acorns, blackberries, sunflowers, and hickory nuts.

The agriculturalists had a high carbohydrate, low protein diet. They grew corn, beans, and pumpkin, and they gathered a wide range of wild plants. Wild animals such as deer, elk, turkey, turtle, and fish were eaten but constituted a much smaller proportion of the diet. Corn provided a weaning food for young children.

The primary sources of data were:

analyses of animal and plant remains to assess types of food eaten
skeletal analyses giving estimates of age at death and life expectancies
analysis of long bones for evidence of growth arrest due to malnutrition or infection
analysis of teeth for evidence of growth arrest, malnutrition, caries, and abscesses
analysis of skulls for evidence of iron-deficiency anemia

Evidence of malnutrition and growth arrest could be seen in:

Harris’ Lines (bone scars) in the tibia (the inner and larger bone of the leg between the knee and ankle; also called the shinbone). These are lines of heavier deposition of calcified material which appear in childhood following malnutrition.
Enamel hypoplasia on the teeth. This shows up as horizontal lines, pits, or grooves on the teeth and is caused by malnutrition in childhood. (See the photograph on p. 146 of McElroy/Townsend).
Periosteal inflammation, changes in the long bones with thickening or development of stripes of smooth material or of rough, porous patches on the bone surfaces. On X-rays the bones show a layering, "onion-skin" effect in young children. This syndrome is evidence of infection; the disease may have been treponematosis (similar to present day yaws, pinta, and syphilis).
Tooth decay, as indicated by caries ("cavities") and by tooth abscesses (infection of the pulp cavity)
Porotic hyperostosis of the skull; these lesions are caused by iron-deficiency anemia (see the photographs on pp. 147 and 150 of McElroy/Townsend).

hunter-gatherers farmers

Findings of the study

infant mortality	higher, birth-12 months	lower, birth-12 months
child mortality	44% died before age 17	54% died before age 17 high death rates ages 1-4
av. life expectancy	at age 18, life expectancy is age 36	at age 18, life expectancy is age 30
evidence of growth arrest	present in higher numbers evidence of regular, brief periods of seasonal hunger	present in lower numbers evidence of irregular periods of longer duration (famine)
evidence of iron- deficiency anemia	absent	present in 50% of children under 5 years old
evidence of infection inflammation in bones	present in lower numbers	present in higher numbers
tooth decay, abscesses	low rate, average of 1 caries some tooth loss in old age due to wear	high rate, average of 7 caries tooth loss in children

Conclusions of the study:

1. In general, the health of the hunter-gatherers was better than the agriculturalists. Hunters had superior nutrition, especially in childhood. Child mortality was especially high in farming villages around the time of weaning, ages 2-4, probably due to higher rates of disease, both nutritional and infectious.

2. Birth and early infancy were more dangerous stages in hunting groups than in farming groups. About 15 percent of infants died before age 12 months in hunting groups; around 8 percent of infants of farmers died in the first year. However, in the 1-3 year age group, 20 percent of the farmers’ children died, and only about 12 percent of the hunters’.

3. Life expectancy in both groups was higher in females than in males, and average life expectancy for a newborn female child of a hunting group was considerably higher (average of 23 years) than for a male child of a farming group (average of 16 years). These life expectancies are calculated on the grouping on skeletal material into age intervals; aging in children is based on tooth eruption sequence and bone maturation, whereas in adults it is based on pubic symphysis wear and tooth wear.

4. Children in both groups experienced growth arrest in middle childhood, as indicated by Harris’ Lines (bone scars). An average of 11.3 bone scars were found on hunter-gatherer shinbones, and an average of 4.1 in the farming groups. In the hunters, the distribution of bone scars is very regular, indicating that periods of hunger were normal and seasonal, perhaps every winter. In the farmers, the lines were more random, indicating that famine was irregular but probably more severe. This hypothesis is supported by the fact that enamel hypoplasia, present in both groups, was far more severe in the farming group.

5. The poor dental health of the agriculturalists is probably due to the high sugar content and soft consistency of cultivated food. Adult males had an average of 6.74 caries per mouth; adult females had an average of 8.5 caries. Hunting-gathering adults had an average of 0.73 caries per mouth for males and 0.91 caries for females. The high rate of tooth decay in farmers contributed to high tooth loss and probably high infection rates as well, and in children such tooth problems would seriously interfere with nutrition and growth.

This information is taken from Claire M. Cassidy, "Nutrition and Health in Agriculturalists and Hunter-Gatherers: A Case Study of Two Prehistoric Populations," in Nutritional Anthropology, Norge Jerome, Randy Kandel, and Gretel Pelto, eds., Redgrave Publishing Co, 1980, pp. 117-145.

BONUS QUESTION and Study Guide

For bonus points, answer one of the following 3 questions. Your answer should be about 2 pages. For exam preparation, review all 3.

1. This case study has focused on evidence of malnutrition in skeletal remains. If you were working with a present-day population of farming peoples (either small-scale cultivators or larger-scale farmers), what physical evidence would indicate malnutrition in children? List and describe the symptoms of malnutrition, using information from chapters 5 and 6 of the text and from Dettwyler’s Dancing Skeletons.

2. If farmers have more health problems than hunter-gatherers, as the Cassidy study suggests, why did most human populations shift to food growing as their primary subsistence? What are the advantages? Why is it difficult to return to a foraging existence once people have settled into farming villages?

3. Why are tortillas and beans better than just tortillas? Discuss the dietary deficiencies associated with farming and with industrial lifestyles, and explain how these deficiencies can be avoided through certain combinations of foods and certain food preparation methods. Be sure that your answer addresses the idea of protein complementarity.