Dietary fiber supplementation increases Drosophila melanogaster lifespan and gut microbiota diversity.

Dietary fiber has been shown to have multiple health benefits, including a positive effect on longevity and the gut microbiota. In the present study, Drosophila melanogaster has been chosen as an in vivo model organism to study the health effects of dietary fiber supplementation (DFS). DFS extended the mean half-life of male and female flies, but the absolute lifespan only increased in females. To reveal the underlying mechanisms, we examined the effect of DFS on gut microbiota diversity and abundance, local gut immunity, and the brain proteome. A significant difference in the gut microbial community was observed between groups with and without fiber supplementation, which reduced the gut pathogenic bacterial load. We also observed an upregulated expression of dual oxidase and a modulated expression of Attacin and Diptericin genes in the gut of older flies, possibly delaying the gut dysbiosis connected to the age-related gut immune dysfunction. Brain proteome analysis showed that DFS led to the modulation of metabolic processes connected to mitochondrial biogenesis, the RhoV-GTPase cycle, organelle biogenesis and maintenance, membrane trafficking and vesicle-mediated transport, possibly orchestrated through a gut-brain axis interaction. Taken together, our study shows that DFS can prolong the half-life and lifespan of flies, possibly by promoting a healthier gut environment and delaying the physiological dysbiosis that characterizes the ageing process. However, the RhoV-GTPase cycle at the brain level may deserve more attention in future studies.

Effect of shape, gluten, and mastication effort on in vitro starch digestion and the predicted glycemic index of pasta.

Gluten-containing (GC) and gluten-free (GF) pasta consumption has been growing in recent years. The market offers a wide variety of pasta types, with differences in shape and formulation that influence the mastication process and, consequently, their nutritional behaviors (i.e. starch digestibility and glycemic response). This study investigated the effect of shape, gluten, and structural breakdown on in vitro starch digestibility and predicted the glycemic index (pGI) of GC and GF penne, spaghetti, and risoni. Pasta was cooked and minced to mimic short, intermediate, and long mastication efforts. Short mastication led to a higher number of big particles than intermediate and long mastications for all pasta samples, which was reflected in the different starch digestibility and pGI patterns. Multivariate analysis of variance showed that the three studied factors differently affected the in vitro starch digestion of pasta. Mastication effort, shape, and their interaction mainly affected the starch digestion rate and pGI. Gluten was the major factor in affecting the amount of digested starch. The results suggested that small shapes (i.e. risoni), the presence of gluten, and short mastication effort led to a lower pGI. The findings will be useful for the development of pasta products tailored to fulfill the needs of specific consumers following a rational food design approach.