Nutrition & Food Science
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Item FUNCTIONAL FOODS THAT MANIPULATE THE GUT MICROBIOTA COMPOSITION AND REGULATE THE INTESTINAL IMMUNE SYSTEM-Urtica dioica a CASE STUDY(2024) Fan, Si; Obanda, Diana; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The prevalence of obesity and its comorbidities, such as insulin resistance and type 2 diabetes are major concerns. Diet-induced obesity and insulin resistance are associated with gut microbiota dysbiosis, specifically, a reduction in diversity and an increase in bacteria taxa linked with host tissue inflammation and extra energy harvest. Prevention strategies focusing on modification of diet and physical activity levels are beneficial, effective, and cost-efficient but difficult to maintain in the long term.Urtica dioica is widely used as a food in several cultures and its extract has been widely studied for intervention against several diseases, but the molecular mechanisms involved are unclear. In addition, most studies have focused on the extract but not the plant as a whole food. Because U. dioica exerts pleiotropic effects in several tissues, we hypothesized that its phytochemicals get into the systemic circulation to reach target tissues, such as abdominal adipose tissue and skeletal muscle but also impact obesity and insulin resistance through pathways involving the gut microbiota and ultimately the gut immune system. The data presented herein was acquired in a mouse model of obesity and insulin resistance. Supplementing the food with whole U. dioica vegetable, attenuated high fat (HF) diet-induced weight gain, fat accumulation, insulin resistance and changed the gut microbiota composition, by increasing diversity and promoting the proliferation of species from the genus Clostridium. This taxon has associated with lower body weight and activation of regulatory T cells (Tregs) in the intestinal immune system. In a second study, we confirmed that U. dioica induced T cells antigenic stimulation, promoted the activation of Tregs and overall protected against HF diet inflammation. Furthermore, besides attenuating HF diet induced fat accumulation, U. dioica promoted the browning or beiging of adipose tissue as evidenced by enhanced gene expression of key markers of this process. Brown or beige adipose tissue displays enhanced fat oxidation. Finally using enteroids derived from small intestinal tissue, we show that in presence of excess nutrients, supplementation with U. dioica reduces the amount fatty acids and glucose absorbed. In conclusion, supplementing a HF diet with U. dioica attenuates fat accumulation and insulin resistance via mechanisms involving the gut microbiota composition and function, the gut immune system and associated inflammation and moderation of amounts of macronutrients absorbed.Item Fermenting kale (Brassica oleracea L.) enhances its functional food properties by increasing accessibility of key phytochemicals and reducing antinutritional factors(Wiley, 2024-05-06) Subedi, Ujjwol; Raychaudhuri, Samnhita; Fan, Si; Ogedengbe, Opeyemi; Obanda, Diana N.The properties of kale as a functional food are well established. We sought to determine how fermentation further enhances these properties. We tested different fermentation conditions: (i) spontaneous fermentation with naturally occurring bacteria, (ii) spontaneous fermentation with 2% salt, (iii) Lactococcus lactis, (iv) Lactobacillus acidophilus, (v) mixture of L. lactis and L. acidophilus, (vi) mixture of L. lactis, L. acidophilus, and Clostridium butyricum. We quantified selected bioactive components using high-performance liquid chromatography (HPLC) and antinutritional factors using a gravimetric method and spectrophotometry. We then determined (i) the antioxidant capacity of the vegetable, (ii) anti-inflammation capacity, and (iii) the surface microbiota composition by 16S sequencing. All fermentation methods imparted some benefits. However, fermentation with mixed culture of L. lactis and L. acidophilus was most effective in increasing polyphenols and sulforaphane accessibility, increasing antioxidant activity, and reducing antinutritional factors. Specifically, fermentation with L. lactis and L. acidophilus increased total polyphenols from 8.5 to 10.7 mgGAE/g (milligrams of gallium acid equivalent per gram) and sulforaphane from 960.8 to 1777 μg/g (microgram per gram) but decreased the antinutritional factors oxalate and tannin. Total oxalate was reduced by 49%, while tannin was reduced by 55%–65%. The antioxidant capacity was enhanced but not the anti-inflammation potential. Both unfermented and fermented kale protected equally against lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages and prevented increases in inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 messenger RNA (IL-6 mRNA) expression by 84.3%, 62%, 68%, and 85.5%, respectively. Unfermented and naturally fermented kale had high proportions of sulfur reducing Desulfubrio and Proteobacteria usually associated with inflammation. Fermenting with L. lactis and/or L. acidophilus changed the bacterial proportions, reducing the Proteobacteria while increasing the genera Lactobacilli and Lactococcus. In summary, fermentation enhances the well-known beneficial impacts of kale. Fermentation with mixed cultures of L. lactis and L. acidophilus imparts higher benefits compared to the single cultures or fermentation with native bacteria present in the vegetable.Item Urtica dioica Whole Vegetable as a Functional Food Targeting Fat Accumulation and Insulin Resistance-a Preliminary Study in a Mouse Pre-Diabetic Model(MDPI, 2020-04-10) Fan, Si; Raychaudhuri, Samnhita; Kraus, Olivia; Shahinozzaman, Md; Lofti, Leila; Obanda, Diana N.The shoot of Urtica dioica is used in several cultures as a vegetable or herb. However, not much has been studied about the potential of this plant when consumed as a whole food/vegetable rather than an extract for dietary supplements. In a 12-week dietary intervention study, we tested the effect of U. dioica vegetable on high fat diet induced obesity and insulin resistance in C57BL/6J mice. Mice were fed ad libitum with isocaloric diets containing 10% fat or 45% fat with or without U. dioica. The diet supplemented with U. dioica attenuated high fat diet induced weight gain (p < 0.005; n = 9), fat accumulation in adipose tissue (p < 0.005; n = 9), and whole-body insulin resistance (HOMA-IR index) (p < 0.001; n = 9). Analysis of gene expression in skeletal muscle showed no effect on the constituents of the insulin signaling pathway (AKT, IRS proteins, PI3K, GLUT4, and insulin receptor). Notable genes that impact lipid or glucose metabolism and whose expression was changed by U. dioica include fasting induced adipocyte factor (FIAF) in adipose and skeletal muscle, peroxisome proliferator-activated receptor-α (Ppar-α) and forkhead box protein (FOXO1) in muscle and liver, and Carnitine palmitoyltransferase I (Cpt1) in liver (p < 0.01). We conclude that U. dioica vegetable protects against diet induced obesity through mechanisms involving lipid accumulation and glucose metabolism in skeletal muscle, liver, and adipose tissue.Item Kale Attenuates Inflammation and Modulates Gut Microbial Composition and Function in C57BL/6J Mice with Diet-Induced Obesity(MDPI, 2021-01-24) Shahinozzaman, Md; Raychaudhuri, Samnhita; Fan, Si; Obanda, Diana N.Kale (Brassica oleracea var. acephala) is a vegetable common in most cultures but is less studied as a functional food compared to other cruciferous vegetables, such as broccoli. We investigated the effect of supplementing a high-fat diet (HFD) with kale (HFKV) in C57BL/6J mice. We particularly explored its role in metabolic parameters, gut bacterial composition and diversity using 16S rRNA sequencing, systematically compared changes under each phylum and predicted the functional potential of the altered bacterial community using PICRUSt2. Like other cruciferous vegetables, kale attenuated HFD-induced inflammation. In addition, kale modulated HFD-induced changes in cecal microbiota composition. The HFD lowered bacterial diversity, increased the Firmicutes: Bacteroidetes (F/B) ratio and altered composition. Specifically, it lowered Actinobacteria and Bacteroidetes (Bacteroidia, Rikenellaceae and Prevotellaceae) but increased Firmicutes (mainly class Bacilli). Kale supplementation lowered the F/B ratio, increased both alpha and beta diversity and reduced class Bacilli and Erysipelotrichi but had no effect on Clostridia. Within Actinobacteria, HFKV particularly increased Coriobacteriales/Coriobacteriaceae about four-fold compared to the HFD (p < 0.05). Among Bacteroidia, HFKV increased the species Bacteroides thetaiotaomicron by over two-fold (p = 0.05) compared to the HFD. This species produces plant polysaccharide digesting enzymes. Compared to the HFD, kale supplementation enhanced several bacterial metabolic functions, including glycan degradation, thiamine metabolism and xenobiotic metabolism. Our findings provide evidence that kale is a functional food that modulates the microbiota and changes in inflammation phenotype.