Digested or Extracted? Edible Insect Effects on Human Cells and Probiotics

The global demand for sustainable protein has brought edible insects into focus as an eco-friendly alternative to conventional livestock, given their reduced resource needs and lower greenhouse gas emissions. Although their safety is widely supported by existing research, widespread consumer acceptance is still lacking.

Therefore, this study explored the influence of different sample preparation techniques on cytotoxicity and probiotic interactions. We tested three commonly consumed insect species—Tenebrio molitor (yellow mealworm), Acheta domesticus (house cricket), and Locusta migratoria (migratory locust). Samples were processed using two methods: simulated gastrointestinal digestion based on the INFOGEST protocol (5 g per sample) and ethanol extraction with 80% ethanol for 24 hours, followed by evaporation and resuspension in DMSO (final concentration: 51.2 mg/mL). All samples were sterile-filtered (0.22 µm). Cytotoxic effects were assessed in non-differentiated human intestinal cell lines (Caco-2 and HT29) using the MTT assay. Both digested and ethanol-extracted samples were tested in a concentration range of 10–0.31% for digested samples and 512–16 µg/mL for extracts. In parallel, we evaluated the ability of selected probiotic strains (Lactobacillus gasseri, Lacticaseibacillus rhamnosus, and L. brevis) to adhere to these epithelial models in the presence of insect-derived samples, which were tested at concentrations of 1, 0.75, and 0.5% for digested material.

Our results showed that the ethanolic extracts were non-toxic to both cell lines, whereas digested samples exhibited dose-dependent cytotoxicity, with IC₅₀ values around 2.5% of the original digest. Because probiotic adhesion is influenced by both the insect species and the preparation of samples, suggesting a range of bioactive compounds, these findings indicate that previously published safety assessments, often based on selected extracts or simplified models, may not fully capture the complexity of biological responses, and their interpretation should therefore be approached with appropriate caution.