The Role of the Gut Microbiota in the Relationship Between Diet and Human Health.

The interplay between diet, the gut microbiome, and host health is complex. Diets associated with health have many similarities: high fiber, unsaturated fatty acids, and polyphenols while being low in saturated fats, sodium, and refined carbohydrates. Over the past several decades, dietary patterns have changed significantly in Westernized nations with the increased consumption of calorically dense ultraprocessed foods low in fiber and high in saturated fats, salt, and refined carbohydrates, leading to numerous negative health consequences including obesity, metabolic syndrome, and cardiovascular disease. The gut microbiota is an environmental factor that interacts with diet and may also have an impact on health outcomes, many of which involve metabolites produced by the microbiota from dietary components that can impact the host. This review focuses on our current understanding of the complex relationship between diet, the gut microbiota, and host health, with examples of how diet can support health, increase an individual's risk for disease, and be used as a therapy for specific diseases.

Presenting symptoms in inflammatory bowel disease: descriptive analysis of a community-based inception cohort.

BACKGROUND: Few data are currently available on the initial presenting symptoms of patients with inflammatory bowel disease (IBD). METHODS: We evaluated the initial symptom presentation of patients with IBD in the Ocean State Crohn's and Colitis Area Registry (OSCCAR), a community-based inception cohort that enrolled Rhode Island IBD patients at time of diagnosis with longitudinal follow up. A 41-question symptom inventory was administered at time of enrollment to capture symptoms experienced during the 4 weeks preceding diagnosis of IBD. Frequencies of presenting symptoms were calculated. Principal component analysis (PCA) with promax rotation was used to examine possible symptom profiles among Crohn's disease (CD) and ulcerative colitis (UC) patients, respectively. Using the Scree plot, the 4-component solution was found to be optimal for both CD and UC. RESULTS: A total of 233 CD and 150 UC patients were included. The most common presenting symptoms in CD were tiredness/fatigue (80.6%) and abdominal pain (80.4%) while passage of blood with bowel movements (BM) (86.6%) and loose/watery BMs (86.5%) were most common in UC. The 5 symptoms with greatest differences between UC and CD were passage of blood with BM (UC 86.6%/CD 45.3%), urgent BM (UC 82.5%/CD 63.9%), passage of mucus with BM (UC 67.7%/CD 36.9%), passage of blood from the anus (UC 59.7%/CD 32.1%), and anxiety about distance from bathroom (UC 59%/CD 38.7%). The PCA analysis yielded a 4 symptom components solution for CD and UC. CONCLUSION: The most common presenting symptoms in CD are fatigue and abdominal pain while in UC bloody BM and diarrhea are most common. Distinct symptom phenotypes are seen with PCA analysis. Our study demonstrates symptomatic similarities and differences between CD and UC and suggests that patients may also be classified by symptom phenotype at time of diagnosis.

Targeting pyruvate carboxylase reduces gluconeogenesis and adiposity and improves insulin resistance.

We measured the mRNA and protein expression of the key gluconeogenic enzymes in human liver biopsy specimens and found that only hepatic pyruvate carboxylase protein levels related strongly with glycemia. We assessed the role of pyruvate carboxylase in regulating glucose and lipid metabolism in rats through a loss-of-function approach using a specific antisense oligonucleotide (ASO) to decrease expression predominantly in liver and adipose tissue. Pyruvate carboxylase ASO reduced plasma glucose concentrations and the rate of endogenous glucose production in vivo. Interestingly, pyruvate carboxylase ASO also reduced adiposity, plasma lipid concentrations, and hepatic steatosis in high fat-fed rats and improved hepatic insulin sensitivity. Pyruvate carboxylase ASO had similar effects in Zucker Diabetic Fatty rats. Pyruvate carboxylase ASO did not alter de novo fatty acid synthesis, lipolysis, or hepatocyte fatty acid oxidation. In contrast, the lipid phenotype was attributed to a decrease in hepatic and adipose glycerol synthesis, which is important for fatty acid esterification when dietary fat is in excess. Tissue-specific inhibition of pyruvate carboxylase is a potential therapeutic approach for nonalcoholic fatty liver disease, hepatic insulin resistance, and type 2 diabetes.