Green Tea and Its Relation to Human Gut Microbiome.

Green tea can influence the gut microbiota by either stimulating the growth of specific species or by hindering the development of detrimental ones. At the same time, gut bacteria can metabolize green tea compounds and produce smaller bioactive molecules. Accordingly, green tea benefits could be due to beneficial bacteria or to microbial bioactive metabolites. Therefore, the gut microbiota is likely to act as middle man for, at least, some of the green tea benefits on health. Many health promoting effects of green tea seems to be related to the inter-relation between green tea and gut microbiota. Green tea has proven to be able to correct the microbial dysbiosis that appears during several conditions such as obesity or cancer. On the other hand, tea compounds influence the growth of bacterial species involved in inflammatory processes such as the release of LPS or the modulation of IL production; thus, influencing the development of different chronic diseases. There are many studies trying to link either green tea or green tea phenolic compounds to health benefits via gut microbiota. In this review, we tried to summarize the most recent research in the area.

Assessing the antioxidant and metabolic effect of an alpha-lipoic acid and acetyl-L-carnitine nutraceutical.

Personalized nutrition (PN) is seen as a potentially effective and affordable strategy for the prevention of non-communicable diseases (NCDs). In this study we aimed to evaluate the antioxidant and metabolic effect of a dietary supplement based on alpha-lipoic acid (ALA) and acetyl-L-carnitine (ALC) in order to include this product in a novel PN service. The antioxidant properties of the commercial nutraceutical were investigated at physiological conditions (through in vitro digestion) and at mitochondrial conditions. The metabolic activity was assessed in a human pilot study using a Gas Chromatography-Mass Spectrometry (GC-MS) methodology in dried urine samples. The nutraceutical exerted an elevated antiradical activity and reducing capacity, especially at mitochondrial conditions, after in vitro digestion. This increase in mitochondrial activity was also evidenced in vivo by a significant increase in the urinary phosphate concentration (p â€‹= â€‹0.004). As pro-oxidant effect was reached with the concentration of 4 capsules, 2 capsules at the same time could be a reasonable dose. No adverse effects were recorded in vivo with this dose. Thus, although its metabolic effect was not so conclusive, ALA â€‹+ â€‹ALC combination might be beneficial as a dietary supplement for the prevention of the oxidative stress and an interesting dietary supplement to consider in large scale studies.

An in vitro batch fermentation protocol for studying the contribution of food to gut microbiota composition and functionality.

Knowledge of the effect of foods on gut microbiota composition and functionality is expanding. To isolate the effect of single foods and/or single nutrients (i.e., fiber, polyphenols), this protocol describes an in vitro batch fermentation procedure to be carried out after an in vitro gastrointestinal digestion. Therefore, this is an extension of the previous protocol described by Brodkorb et al. (2019) for studying in vitro digestion. The current protocol uses an oligotrophic fermentation medium with peptone and a high concentration of fecal inoculum from human fecal samples both to provide the microbiota and as the main source of nutrients for the bacteria. This protocol is recommended for screening work to be performed when many food samples are to be studied. It has been used successfully to study gut microbiota fermentation of different foodstuffs, giving insights into their functionality, community structure or ability to degrade particular substances, which can contribute to the development of personalized nutrition strategies. The procedure does not require a specific level of expertise. The protocol takes 4-6 h for preparation of fermentation tubes and 20 h for incubation.