Comparing apples and oranges: Why infant bone collagen may not reflect dietary intake in the same way as dentine collagen

Abstract

ObjectivesRecent developments in incremental dentine analysis allowing increased temporal resolution for tissues formed during the first 1,000 days of life have cast doubt on the veracity of weaning studies using bone collagen carbon (δ13C) and nitrogen (δ15N) isotope ratio data from infants. Here, we compare published bone data from the well‐preserved Anglo‐Saxon site of Raunds Furnells, England, with co‐forming dentine from the same individuals, and investigate the relationship of these with juvenile stature. The high‐resolution isotope data recorded in dentine allow us to investigate the relationship of diet with juvenile stature during this critical period of life.Materials and methodsWe compare incremental dentine collagen δ13C and δ15N data to published bone collagen data for 18 juveniles and 5 female adults from Anglo Saxon Raunds Furnells alongside new data for juvenile skeletal and dental age. An improvement in the method by sampling the first 0.5 mm of the sub‐cuspal or sub‐incisal dentine allows the isotopic measurement of dentine formed in utero.Results and discussionδ13C profiles for both dentine and bone are similar and more robust than δ15N for estimating the age at which weaning foods are introduced. Our results suggest δ15N values from dentine can be used to evaluate the maternal/in utero diet and physiology during pregnancy, and that infant dentine profiles may reflect diet PLUS an element of physiological stress. In particular, bone collagen fails to record the same range of δ15N as co‐forming dentine, especially where growth is stunted, suggesting that infant bone collagen is unreliable for weaning studies.

Using teeth as tools: Investigating the mother–infant dyad and developmental origins of health and disease hypothesis using vitamin D deficiency

“…Given the importance of research into the DOHaD/first 1000 days hypotheses, better understanding the mother-infant pairing has become crucial. Investigations of dentine in deciduous teeth have provided significant information for bioarchaeologists (e.g., Beaumont et al, 2018) and biobanks are an excellent resource for modern groups. To expand potential research, a means of looking back at early life using adult dentition is needed.…”

“…Investigations of dentine in deciduous teeth have provided significant information for bioarchaeologists (e.g., Beaumont et al, 2018) and biobanks are an excellent resource for modern groups. Investigations of dentine in deciduous teeth have provided significant information for bioarchaeologists (e.g., Beaumont et al, 2018) and biobanks are an excellent resource for modern groups.…”

The Whole Tooth and Nothing but the Tooth: Or why Temporal Resolution of Bone Collagen May Be Unreliable

“…In juveniles, where co‐forming dentine and bone do not appear to be recording the same isotopic values, it is possible that there is a “threshold” of stress (where nutrition is inadequate for the prevailing conditions, be they intrinsic or extrinsic) above which bone ceases to grow, whereas teeth, because they are evolutionarily important and buffered (Elamin and Liversidge ), continue to form and record isotopic changes (Beaumont et al . ). This would also explain the lack of isotopic differences in pathological bone, or the epiphyses of growing bones, as new bone may only form in favourable low‐stress conditions.…”

“…Of special interest is the first forming 0.5 mm of dentine in deciduous teeth, which is laid down during the third trimester of pregnancy and thus records the maternal/infant diet and physiology (Beaumont et al . ). The methods used by all researchers still include some blurring of the data because of the overlapping developmental layers sampled by horizontal sectioning of the teeth (Eerkens et al .…”

“…A number of studies using the co‐forming incremental dentine collagen and bone collagen from the same juveniles have shown that the δ 13 C and δ 15 N do not match, and do not overlap, with the δ 15 N higher in dentine than in bone (Beaumont ; Burt ; Burt ; Beaumont et al . ; King et al . ).…”