FAYETTEVILLE -- By studying the teeth of a rare group of hunter-gatherers living in Africa, a University of Arkansas anthropologist hopes to better answer questions about when prehistoric peoples shifted to an agriculture-based lifestyle.
Peter Ungar, chairman of UA's Anthropology Department, said he was surprised to spot dental decay among a group known as the Hadza during a January trip to Tanzania. The Hadza include a group of about 200 to 250 people who rely on a wild-food diet. They forage for berries, tubers and other plants, while also hunting game and collecting honey.
"Their teeth were riddled with cavities, and we weren't expecting to see any at all, because hunter-gatherers are not supposed to have cavities," Ungar said.
He explained when agriculture brings changes to diet, grains such as wheat, sorghum and maize are known to promote tooth decay. Fossil records of dental remains have long been thought to show when people shifted to agriculture-based lifestyles, with their diets dominated by grains as opposed to the broad-based diet of hunter-gatherers.
Ungar said the archeological record in a place such as the ancient region of Mesopotamia, for example, shows the onset of oral disease thought to mark the rise of agriculture.
However, the tooth decay seen among the Hadza "is challenging the conventional wisdom," said Ungar, a dental anthropologist who has written the book, Mammal Teeth, about the evolutionary history of teeth and helped edit another book on the evolution on the human diet.
He'll go return to Tanzania this summer with help from an expedited National Science Foundation grant of about $12,700. The project, also led by University of Nevada, Las Vegas, assistant professor Alyssa Crittenden, follows up on the earlier trip.
Unger said the plan is to have 90 adult participants undergo common dental exam procedures to better understand their oral health, with a laser probe known as a Diagnodent and a dental camera to be used. Ungar said he's working in consultation with a certified general practice dentist.
"We've got our sort of preliminary, pilot result, but now we've got to go in there and roll up our sleeves and do the hard science work -- actually coming up with numbers and proving it," Ungar said.
The expedited grant comes at a time the Hazdas are in transition to a more settled lifestyle. Crittenden said the total Hadza population of about 1,000 has been steady for the past 100 years, but more are now choosing village life.
"They're one of the last foraging populations on the planet," Crittenden said, adding the group of hunter-gatherers are the last population in Africa collecting more than 80 percent of their foods from wild resources.
Part-time foragers also live in Central America, South America, southeast Asia, Australia, Madagascar and Papua New Guinea, Crittenden said.
However, "I can count the number of populations on one hand who are foraging as much as the Hadza," Crittenden said.
She said the research team will provide cooking pots, knives, blankets, beads and shoes for the Hadza as they recruit participants for their study.
"They don't participate in a market economy, so cash wouldn't provide them with a lot of value," Crittenden said.
Along with implications for the understanding of the advent of agriculture, Crittenden said the research provides an important opportunity to study another facet of the human diet.
"We don't really know what a hunter-gather diet in transition looks like, so we're kind of running out of time in order to ask some of these questions," Crittenden said.
NW News on 06/15/2015