Stable isotope analysis in forensic anthropology is used primarily to infer which of the following?

• A. To infer geographic origin and diet by analyzing stable isotopes in bone or tooth enamel
• B. To measure bone mineral density
• C. To determine time since death from isotopic decay
• D. To identify infectious disease markers

Answer: (A)

Stable isotope analysis looks at natural variations in the ratios of certain isotopes in human tissues to read back about the environment and diet during life. Because the isotopic makeup of local water, foods, and geology differs by region, these signatures become embedded in tissues like tooth enamel and bone.

Tooth enamel forms in childhood and doesn’t remodel much, so its isotopic composition records where a person grew up and what they ate during early life. Bone, which continually remodels, reflects diet and geography from more recent periods of life. The isotopes most informative here include carbon and nitrogen, which reveal dietary patterns (carbon distinguishes plant types and whether foods are marine or terrestrial; nitrogen indicates trophic level). Strontium and oxygen isotopes provide geographic information, since strontium mirrors local geology through food and water, and oxygen reflects drinking water sources and climate.

Thus, the main application is inferring geographic origin and diet from the isotopic signatures in bone or tooth enamel. It isn’t used for measuring bone mineral density, for dating time since death through isotopic decay, or for identifying infectious disease markers.