To obtain an accurate picture of palaeodiets, it is important to understand processes of diagenesis that may affect the original isotopic signal.
It is also important for the researcher to know the variations of isotopes within individuals, between individuals, and over time.
While teeth are more resistant to chemical and physical changes over time, both are subject to post-depositional diagenesis.
Bone is continually remodelled throughout the lifetime of an individual.
Certain isotopes can signify distinct primary producers forming the bases of food webs and trophic level positioning.
The stable isotope compositions are expressed in terms of delta values (δ) in permil (‰), i.e. They express the proportion of an isotope that is in a sample.
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis.
Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; These isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.