Light Stable Isotope Ratios of US Pureed Baby Foods

Abstract

Rationale

The isotopic composition of foods is useful for verifying origin and provides baseline information for interpreting isotopic data from human tissues in dietary and forensic research. Despite their widespread consumption, baby foods in the United States remain isotopically understudied. This study presents and analyzes an exploratory δ²H, δ¹⁸O, δ¹³C, and δ¹⁵N dataset for pureed baby foods spanning different food types, labeling designations, brands, and geographic purchase locations.

Methods

Pureed baby food was collected from across the United States, focusing on three widely consumed food types (banana, carrot, and sweet potato, n = 117) across several commercial brands. Cryogenically extracted water and residual dry solids were analyzed to determine the δ²H and δ¹⁸O values of water and δ¹³C and δ¹⁵N values of bulk solids.

Results

We found significant isotopic differences between food types, with bananas having the highest δ²H, δ¹⁸O, and δ¹³C values and carrots the lowest. These offsets persisted across different brands. No significant differences were observed across purchase locations. δ¹⁵N values were significantly higher for bananas and carrots labeled “organic,” and d-excess and δ¹⁸O values in banana and sweet potatoes were significantly higher for foods containing added water.

Conclusions

Our dataset documents isotopic patterns in pureed baby foods aligning with expectations related to differences in growing environment, farming practices (e.g., organic), and processing (e.g., added water). This supports the potential utility of stable isotope data for studying and authenticating baby food production and distribution. Although limited in sample size, the absence of geographic isotopic variation, which is consistent with geographic homogenization of the modern “supermarket diet,” suggests isotopic inputs from food to bodies of infants and children consuming these prepared foods depend more on consumer choices than on location. Thus, early childhood isotope data may be more informative for reconstructing diet than residence.