## 3 Results
### Effects of Phytochemicals on the Intestinal Microbiome, Obesity and Metabolic Syndrome  
A randomized double-blind crossover trial investigated the hypolipidemic activity of curcumin in obese subjects. Each participant consumed curcuminoids or placebo for 30 days and then switched to the other regimen. Sixteen subjects consumed curcuminoids 1 g/day for 30 days and/or a placebo for 30 days. Curcuminoids were given in capsules containing 500 mg curcuminoids and 5 mg bioperine, an extract made of black pepper (_Piper nigrum_ L.) or long pepper (_Piper longum_ L.) containing 95% piperine, a well-known bioavailability enhancer. Placebo capsules had the same size and shape as the curcuminoid capsules and contained piperine (5 mg). In this study, it was observed that curcuminoid supplementation (1 g/day for 30 days) intensely decreased plasma TG, possibly due to the insulin-sensitizing effects of this phytochemical. Dyslipidemia is an important risk factor for cardiovascular disease and is a common constituent of obesity. Curcumin is a bioactive phytochemical with well-documented antioxidant, anti-inflammatory, and cardioprotective properties. Evidence suggests that obese people have an increased risk of IR syndrome and diabetes mellitus. This increased risk is the result of the pathophysiological modifications in the secretion of adipokines and inflammatory cytokines by the adipose tissue. The \begin{table}
\begin{tabular}{|p{113.8 pt}|p{113.8 pt}|p{113.8 pt}|p{113.8 pt}|p{113.8 pt}|} \hline
**Study Type** & **Study Sample/Duration** & **Participants** & **Protocol** & **Summary of Results** & **Study Reference** \\ \hline A randomized, double-blind, placebo-controlled trial & 37 participants/12 weeks & Adults with overweight and obesity. & 21 g of oligofructose or a maltodextrin placebo. & 40\% reduction in LPS concentrations in the oligofructose group compared to a 48\% increase in the placebo group. PAI-1 was reduced to a greater extent in the oligofructose group. & 40\% reduction in LPS concentrations in the oligofructose group. & [37] \\ \hline Triple-blind randomized controlled study & 54 patients/8 weeks & diabetic females aged 20-65 years. & The intervention group consumed 10 g/d inulin supplement and the control group consumed similar amounts of maltodextrin. & [38] \\ \hline A placebo-controlled crossover study & 25 patients (15 men)/6 weeks & Adult men and women with type 2 diabetes/41-71 y. & Consumption of 16 g of inulin-type fractans (a mixture of oligofructose and inulin) and 16 g placebo (malodextrin) in a randomized order. & [38] \\ \hline Single-center, double-blind placebo-controlled trial & 38 children /16 weeks & Male and female children & Supplementation of children, 20 in the prebiotic group and 18 in the control group, aged placebo once daily for 16 weeks. & Consumption of & [40] \\ \hline \end{tabular}
\end{table} 
Table 3: Summary results of prebiotics effects on human microbiome related to metabolic diseases. amelioration of adipokine status, in addition to the anti-inflammatory effects of curcumin, are possible mechanisms responsible for its beneficial effects on IR [41]. The aim of another double-blind, placebo-controlled, crossover study was to investigate the impact of polyphenol-rich tomato extract (Fruitflow) on trimethylamine N-oxide (TMAO) and gut microbiota. Twenty-two overweight and obese adults were separated into two groups and received 2150 mg of extract per day in one group or placebo (maltodextrin) in the other group for 4 weeks, with a 6-week washout period. Fruitflow decreased urine TMAO, which possesses proinflammatory and proatherogenic action, as well as plasma LPS. Furthermore, there were significant modifications of microbial taxa with Fruitflow, such as a reduction in Bacteroides, Ruminococcus, and Hungatella, as well as an increase in Alistipes, a member of Bacteroidetes phylum known for its involvement in TMA/TMAO metabolism.