Lactiplantibacillus plantarum, Duodenal Hydroxyphenyllactic Acid and Iron: Insights from a Rat Model of a High-Fat Iron-Deficient Diet

Background: Lactiplantibacillus plantarum synthesizes in vitro hydroxyphenyllactic acid (HPLA)—an iron-reducing agent supposed to facilitate duodenal Fe absorption. So far, no such in vivo HPLA production has been established. This study aimed to investigate the ability of Lactiplantibacillus plantarum to produce HPLA in the duodenum in rats on a high-fat iron-deficient diet. Methods: Rats were fed a high fat (HF) diet; HF, Fe-deficient diet (HFDEF); or control (C) diet for 8 weeks. Over the next 8 weeks, animals in the C and HF groups continued on their respective diets, while animals in the HFDEF group were divided into six subgroups and received combinations of an HF, Fe-deficient diet with Lactiplantibacillus plantarum (Lp), Latilactobacillus curvatus (Lc), and Fe supplementation (HFDEF, HFDEFFe, HFDEFLp, HFDEFLc, HFDEFFeLp, and HFDEFFeLc). Duodenal and faecal samples were collected. Results: No significant differences were observed in HPLA content in the duodenum and faeces, nor in Fe chelating abilities in faeces, between study groups at the completion of the study. Fe content in faeces was higher in the HFDEFFe group than in the C, HF, HFDEF, HFDEFLp, and HFDEFLc groups. Fe content in faeces was higher in the HFDEFFeLp and HFDEFFeLc groups than in the HFDEF and HFDEFLc groups. Conclusions: Lactiplantibacillus plantarum, whether alone or with oral Fe, does not influence duodenal and faecal HPLA content, nor does it affect faecal Fe chelating abilities in rats on the HF, Fe-deficient diet.