After the publication of a paper with an extremely strong Irish flavour in PLOS ONE in August, Julia Beaumont reflects on the events and pathways which have led her to this point

I consider myself to have been lucky to have two very different, fascinating and rewarding careers in clinical dentistry and biological anthropology. I am sure that the first was a huge factor in my ability to propose and carry out research using the scientific methods I have been taught during my studies at the School of Archaeological Sciences at the University of Bradford.

I studied for my first degree at the University of Manchester and thoroughly enjoyed the course, a mixture of academic thought and apprenticeship in the hands-on art of dentistry. I always loved the practical side, and once in community service, and then in practice in the north of England, found myself drawn to orthodontics as part of my working week. With my then husband, we set up a chain of three small practices, with the challenges over a 30-year period of managing businesses and staff and navigating the NHS and private practice. I make the joke that I am easily bored, and in fact always carried on some kind of studying, accumulating A-levels in psychology and archaeology, a Spanish course, and a certificate in business management.

After the archaeology A-level, I accompanied my eldest daughter on her rounds of the universities of northern Britain and, at Bradford, wandered across the corridor to talk to the archaeologists. Within minutes, the head of department sat me with a lecturer who was carrying out groundbreaking research into the chemicals incorporated into the enamel from the diet during tooth development. Janet Montgomery had also been a mature student (not as mature as me!) and her work on animal and human migration in the archaeological past was a revelation. Her background research meant that her knowledge of dental development was comprehensive and thoughtful in terms of what this meant for establishing the age at which the geographical signatures for climate and geology were being incorporated into the teeth.

I was hooked! I applied to join the master’s course in Human Osteology and Palaeopathology in Bradford, and gave up my two days in orthodontic specialist practice to study part-time. My dissertation was with Janet as my supervisor, and the title Timelines in Teeth was also used for her NERC-funded grant on which I worked as a research assistant.

This was not an easy transition. Compared with shiny new graduates, I had a real lack of skills. I had never used PowerPoint, never written an essay on a word processor, and never used references. In my first year, the written work was pretty average in contrast to the practical side, which I loved. Fellow students took this older person under their wings, and showed me how they were achieving high marks.

A watershed moment was in the osteology lab. Two of the professors and I were leaning over a beautifully-preserved laid-out skeleton from the Bradford collection, with some obvious but undiagnosable pathology in the maxillary antrum. I tentatively suggested some differential diagnoses, and found that my opinion was not only accepted, but became a discussion between us all. Knowing that there was no ‘right answer’ and the evidence had to be collected and researched gave me the confidence to start pursuing ideas of my own.

After some arm twisting, I agreed to continue part-time as a PhD student. The project involved using a well-established technique of analysing bone collagen from individual burials to reconstruct their diet, but in the context of a ı9th-century London graveyard which had strong links with Irish migration during the Great Irish Famine. I measured the purified bone collagen for the isotope ratios of carbon and nitrogen from ı20 individuals in order to establish the range of values and what these might mean. The question was, could I identify migrants from the famine who died and were buried in London?

Theoretically we would see a big difference between the mixed-source London diet and the Irish potato-based diet of the expected migrants to this area of London.

The early results were encouraging. Not only could we see some individuals who fitted the expected London and Irish diets, I also found a Portuguese mariner with a very marine-based diet (and a death certificate).

Here is where serendipity intervenes. At a conference, I was introduced to an archaeologist who was excavating an unknown cemetery in Kilkenny, which turned out to contain more than 600 individuals buried during the famine in the grounds of the Kilkenny Union workhouse. His osteological analysis was to form the basis of his PhD thesis, several excellent papers, and a book which combined the archaeology, osteology and his detailed documentary research. Jonny Geber was kind enough to be interested in my Londoners and particularly in a new technique I was pioneering.

With my knowledge of dental development, I spent a year trying different ways of sectioning teeth in order to find the smallest samples I could use to get good quality isotope ratios. Each section was then assigned an approximate age according to the developmental age range of the tooth sampled. In some cases, these running averages showed dramatic changes in the diet during the childhood period, which could be interpreted as changes in diet consistent with an Irish childhood and a London adolescence.

With Jonny’s help we applied to the National Museum of Ireland for permission to take bone and tooth samples from 20 of the individuals from Kilkenny. Working in a cellar in Dublin, we then chose a mixture of adults and children, males and females, old and young.

Once I applied the technique to these teeth, I realised that we’d found something that would not only illuminate the last years of the children who died in this workhouse community, but also add to the way in which these collagen isotope ratios were interpreted. I found a dramatic shift in the values of the children’s diets consistent with the historical evidence for the introduction of maize (corn) as a relief food. The carbon isotope ratios from the diet shifted from one consistent with potatoes to one which was reflecting the majority of their calorie intake from maize.

Intriguingly, we could see the same pattern in the tooth of an adult female. In most of them there was a further mystery – the nitrogen isotope ratios were raised just before the maize appeared, a change usually associated with the introduction of a higher quality protein in the diet, such as meat or fish. This was very unlikely in a child just about to be admitted to the workhouse, but another explanation was possible.

When a person doesn’t have sufficient protein in the diet, new body tissues are formed by the recycling of old proteins, and this can give the same sort of shift in the nitrogen isotope ratio. A further factor was that the carbon isotope ratio should rise at the same time, but not to the same extent, as the nitrogen if this was a dietary change. In the case of these children, the carbon was flat, or even moved in the opposite direction. One explanation for this could be the mobilisation of fat stores which have a lower carbon isotope ratio, which was then incorporated into the newly-formed tissues.

While some of these changes had been identified in the hair of modern clinical cases, this was the first time that sufficient resolution was possible to identify short-term changes in diet and physiology using dentine.

The PLOS ONE paper sets out the data from the 20 Kilkenny individuals and the arguments for this pattern. It not only reflects a real marker for nutritional stress within dentine, but also the potential for it to be used in archaeological cases where nutritional stress is a factor in their lives, as well as to investigate potential forensic cases of neglect where a tooth is available for analysis.

Since the PhD was completed, I have become a member of staff at Bradford, a full-time lecturer post which gives me the opportunity to carry out research and to teach a research-led curriculum within the school. Research means never being bored! While I enjoyed my years as a dentist, I’m grateful for the opportunity to apply the knowledge in a novel way.

So what next? Well, the study of perinatal health and the effect of this on adult life (the developmental origin of health and disease, or the DOHaD hypothesis) starts with the ability to identify stress in maternal and infant health. Analysing deciduous teeth which start to form in utero offers a chance to reconstruct the diet and physiology of this mother/infant pair.

My collaborators and I have sampled a wide range of archaeological children paired with adult females from the same burial sites, and I am currently using the money from the Rank Prize Nutrition Fund New Lecturer Award to collect modern extracted teeth and perinatal history in a clinic in Bradford in order to test the hypothesis.

And my final career change? I am now the Bradford Tooth fairy!

About the author

Julia qualified as a dentist with BDS from the University of Manchester in 1982 and practised as a dentist and orthodontist in East Lancashire for 30 years until 2012.

She was a clinical audit leader for the BDA and held posts as dental adviser to three Primary Care Trusts, and also to Oasis Dentalcare. During this time, she studied part-time to obtain the MSc in human osteology and palaeopathology from the University of Bradford in 2007.

Her PhD, entitled ‘An isotopic and historical study of diet and migration during the
Great Irish Potato Famine (1845-1852)’, was awarded by the University of Bradford in 2013.