Scope Obesity prevalence continues to increase and contribute to metabolic diseases, potentially by driving systemic inflammation. Curcumin is an anti‐inflammatory spice with claimed health benefits. However, mechanisms by which curcumin may reduce obesity‐associated inflammation are poorly understood; thus, it is hypothesized that benefits of curcumin consumption may occur through reduced white adipose tissue (WAT) inflammation and/or beneficial changes in gut bacteria. Methods and Results Male B6 mice are fed high‐fat diets (HFD, 45% kcal fat) or HFD supplemented with 0.4% (w/w) curcumin (HFC) for 14 weeks. Curcumin supplementation significantly reduces adiposity and total macrophage infiltration in WAT, compared to HFD group, consistent with reduced mRNA levels of M1 (Cd80, Cd38, Cd11c) and M2 (Arginase‐1) macrophage markers. Moreover, curcumin supplementation reduces expression of other key pro‐inflammatory genes, such as NF‐κB p65 subunit (p65), Stat1, Tlr4, and Il6, in WAT (p < 0.05). Using microbial 16S RNA sequencing, it is demonstrated that the relative abundance of the Lactococcus, Parasutterella, and Turicibacter genera are increased in the HFC group versus HFD. Conclusions Curcumin exerts protective metabolic effects in dietary obesity, in part through downregulation of adipose tissue inflammation, which may be mediated by alterations in composition of gut microbiota, and metabolism of curcumin into curcumin‐O‐glucuronide.

The influence of diet on the gut microbiota is an emerging research area with significant impact on human health and disease. However, the effects of beef, the most consumed red meat in the United States, on gut microbial profile are not well studied. Following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, the objective of this systematic review was to conduct a rigorous and thorough review of the current scientific literature regarding the effects of beef protein and the resulting bioactivity of beef protein and amino acids on the gut microbiota, with the goal of identifying gaps in the literature and guiding future research priorities. Utilizing MEDLINE Complete, PubMed, ScienceDirect, Scopus, and Google Scholar databases, we conducted searches including terms and combinations of the following: animal protein, amino acid, beef, bioactive compounds, diet, health, microbiome, peptide, processed beef, and protein. We identified 131 articles, from which 15 were included in our review. The effects of beef on mouse and rat models were mostly consistent for the bacterial phylum level. Short-term (1–4-wk) beef intakes had little to no effect on microbial profiles in humans. Most studies utilized high beef feeding (240–380 g/d), and no study examined recommended amounts of protein [∼3.71 oz/d (105 g/d) meats, poultry, and eggs, or ∼26 oz/week (737 g/wk) from these food sources] according to US dietary guidelines. Additionally, the majority of animal and human studies with adverse findings examined the impact of beef in the context of a diet high in fat or sugar. In conclusion, an extensive gap exists in the literature regarding beef and the microbiota. More studies are necessary to elucidate the role of the microbiota following the consumption of beef, especially in interaction with other dietary compounds, and how beef preparation, processing, and cooking methods differentially influence the biological effects of beef on human health.

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Objectives Curcumin, a traditionally used spice in Asia has several health-protecting effects. However, its role on gut microbiota and obesity-associated inflammation is still poorly understood. The objective of this study was to determine whether the protective effects of curcumin in high fat diet (HFD)-induced obesity are mediated by reduced white adipose tissue (WAT) inflammation and changes in gut bacteria. Methods Male B6 mice were fed a HFD (45% kcal fat) or HFD supplemented with 0.4% (w/w) curcumin (HFC) for thirteen weeks. Body weight, adiposity, glucose and, insulin tolerances, and serum triglycerides, insulin, leptin, resistin levels were measured. Gut microbiome composition was determined by 16S RNA metagenomics sequencing. Expression of inflammation-related genes in WAT was measured by qRT-PCR. Macrophage contents in WAT were evaluated by galectin-3 immunohistochemical staining. Results Pro-inflammatory transcription factor nuclear factor NF-kappa-B p65 subunit (p65) and toll-like receptor-4 (TLR-4) gene expression was downregulated in HFC group compared to HFD mice. Furthermore, curcumin reduced total macrophage infiltration in WAT in HFC mice compared to HFD group. Expression of both M1 (CD80, CD38) and M2 (Arginase-1) associated genes was decreased. The relative abundance of bacteria representing the Clostridium genus, which contains numerous short-chain fatty acid (SCFA) producing species, was increased by the curcumin supplement. Conclusions Curcumin exerts protective effects in dietary obesity, in part through downregulation of adipose tissue inflammation which may be due to the production of SCFA and, possibly other curcumin metabolites by gut microflora. Funding Sources Startup funds and Come N Go award from the College of Human Sciences at Texas Tech University.

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