Omega-3 and conjugated fatty acids impact on human microbiota modulation using an in vitro fecal fermentation model

Background & aims: Gut microbiota has been gaining increasing attention and its important role in the maintenance of a general good health condition is already established. The potential of gut microbiota modulation through diet is an important research focus to be considered. Lipids, as omega-3 fatty acids, are well known for their beneficial role on organs and corresponding diseases. However, their impact on gut microbiota is still poorly defined, and studies on the role of other polyunsaturated fatty acids, such as conjugated linoleic and linolenic acids, are even scarcer. Methods: By using an in vitro human fermentation model, we assessed the effect of omega-3, CLA isomers, and punicic acid on microbiota modulation. Results: Fish oil, Omega-3, and CLA samples positively impact Akkermansia spp. and Bifidobacterium spp. growth. Moreover, all the samples supported Roseburia spp. growth after 24 h of fermentation and, importantly, they were able to maintain the Firmicutes: Bacteroidetes ratio near 1. All the bioactive fatty acid samples, except Pomegranate oil, were able to significantly increase butyrate levels compared to those found in the positive control (FOS) sample. Moreover, Fish oil and Omega-3 samples were able to increase the concentration of GABA, alanine, tyrosine, phenylalanine, isoleucine, and leucine between 12 and 24 h of fermentation. Conclusions: The impact of the assessed polyunsaturated fatty acids in gut microbiota has been observed in its impact on key bacteria (Akkermansia, Bifidobacterium, and Roseburia) as well as their metabolic byproducts, including butyrate and amino acids, which could potentially play a role in modulating the gut-brain axis. (c) 2025 Published by Elsevier Ltd.