Oral health key to understanding humanity's past, study says

The findings, published today in the Journal PLoS One, looked at oral health of the current day Hadza tribe in Tanzania, Africa -- some of the last known hunter-gatherers -- as their life style changes from foraging for wild foods to an agricultural based diet.

Anthropologists have long held that neolithic humans transitioning thousands of years ago from hunting and gathering to farm based diets often suffered from tooth decay and gum disease. This contributed to suggestions that humans are better off with a wild-food based diet as opposed to one where staples might be foods like corn or potatoes.

However, research by Alyssa Crittenden, Lincy Assistant Professor of Anthropology at UNLV, Peter Ungar, Distinguished Professor of Anthropology at the University of Arkansas, and New York dentist John Sorrentino suggests that may not be the case.

"The Hadza offer us a window into the past and challenges the prevailing assumption that foragers were healthier than after they switched to an agricultural diet based on cereals such as corn and wheat," Crittenden said. "For example, our results show that a person's sex and where they live really influences how healthy their teeth are."

Unger explained, "The transition from hunting and gathering to agriculture is routinely associated with declines in oral health, because of increased consumption of carbohydrates and growth of bacterial colonies in dental plaque linked to the development of tooth decay."

By studying the Hadza tribe the research team showed oral health was greatly influenced by gender, residence, and behavior. For instance, men living in the bush suffered greatly from tooth decay and other oral health issues, likely because they use their teeth as tools to make hunting instruments such as arrows and smoke more tobacco -- which can lead to cavities. However, Hadza men living in the village who have transitioned to an agricultural diet show a marked difference in oral health and have healthier teeth and gums.

Conversely, women living on wild-food diets in the bush had the best oral health and women living on agricultural diets in villages had the worst teeth. These patterns show that diet and sex interact to lead to oral health outcomes -- something that has been often overlooked among transitioning populations.

"The presumptions we have long held about oral health and the transition from a foraging to an agricultural diet are not as clear cut as we once thought," Crittenden said.

The team, which also includes co-author Sheniz Moonie, Associate Professor in the School of Community Health Sciences at UNLV, has also discovered that several variables can influence tooth decay in addition to diet and gender. These include a person's bacterial environment, oral microbiome, eating frequency, the rate of dental wear, and even genetic predisposition.

The team plans to further study the role that each factor may play in overall health as the Hadza continue their transition away from foraging.