Ketogenic Diet: A Dietary Intervention via Gut Microbiome Modulation for the Treatment of Neurological and Nutritional Disorders (a Narrative Review).

The ketogenic diet (KD) has been important in treating epilepsy since the 1920s. The benefits of KD further expanded to other neurological diseases, including Alzheimer's diseases, autism spectrum disorder, and nutritional disorder (obesity). Although the therapeutic efficacy of KD has been generally accepted, there is limited knowledge about its underlying mechanism of action, particularly its effect on our gut microbiome. Gut dysbiosis has been proposed to be involved in those diseases, and KD can promote gut microbiota remodeling that may assist in recovery. This review explores the therapeutic applications of KD, the roles of the gut microbiome in neurological diseases and obesity, as well as the effect of KD on the gut microbiome. The present information suggests that KD has significant roles in altering the gut microbiome to improve disease symptoms, mainly by incrementing Bacteroidetes to Firmicutes (B/F) ratio and reducing Proteobacteria in certain cases. However, current gaps call for continued research to understand better the gut microbiota profile altered by KD.

Understanding the gut microbiota and sarcopenia: a systematic review.

BACKGROUND: Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut-muscle axis has been raised, the casual relationship is still unclear. This systematic review analyses the current evidence of gut microbiota effects on muscle/sarcopenia. METHODS: A systematic review was performed in PubMed, Embase, Web of Science, and The Cochrane Library databases using the keywords (microbiota* OR microbiome*) AND (sarcopen* OR muscle). Studies reporting the alterations of gut microbiota and muscle/physical performance were analysed. RESULTS: A total of 26 pre-clinical and 10 clinical studies were included. For animal studies, three revealed age-related changes and relationships between gut microbiota and muscle. Three studies focused on muscle characteristics of germ-free mice. Seventy-five per cent of eight faecal microbiota transplantation studies showed that the recipient mice successfully replicated the muscle phenotype of donors. There were positive effects on muscle from seven probiotics, two prebiotics, and short-chain fatty acids (SCFAs). Ten studies investigated on other dietary supplements, antibiotics, exercise, and food withdrawal that affected both muscle and gut microbiota. Twelve studies explored the potential mechanisms of the gut-muscle axis. For clinical studies, 6 studies recruited 676 elderly people (72.8 ± 5.6 years, 57.8% female), while 4 studies focused on 244 young adults (29.7 ± 7.8 years, 55.4% female). The associations of gut microbiota and muscle had been shown in four observational studies. Probiotics, prebiotics, synbiotics, fermented milk, caloric restriction, and exercise in six studies displayed inconsistent effects on muscle mass, function, and gut microbiota. CONCLUSIONS: Altering the gut microbiota through bacteria depletion, faecal transplantation, and various supplements was shown to directly affect muscle phenotypes. Probiotics, prebiotics, SCFAs, and bacterial products are potential novel therapies to enhance muscle mass and physical performance. Lactobacillus and Bifidobacterium strains restored age-related muscle loss. Potential mechanisms of microbiome modulating muscle mainly include protein, energy, lipid, and glucose metabolism, inflammation level, neuromuscular junction, and mitochondrial function. The role of the gut microbiota in the development of muscle loss during aging is a crucial area that requires further studies for translation to patients.

Noneffectiveness of electroacupuncture for comorbid generalized anxiety disorder and irritable bowel syndrome.

BACKGROUND AND AIM: Comorbid generalized anxiety disorder and irritable bowel syndrome are common and therapeutically challenging. We aimed to assess the effectiveness of electroacupuncture in relieving anxiety and bowel symptoms in Chinese adults with this form of comorbidity. METHODS: In a single-blind randomized sham-controlled trial, subjects with comorbid generalized anxiety disorder and irritable bowel syndrome were randomly assigned to receive 10 weekly sessions of electroacupuncture or sham electroacupuncture. Patients were assessed at baseline, immediately after intervention and at 6-week follow-up. Primary outcome was anxiety (7-item Patient Health Questionnaire section for anxiety). Secondary outcomes included bowel symptoms (bowel symptoms questionnaire), depressive symptoms (9-item Patient Health Questionnaire), somatic symptoms (15-item Patient Health Questionnaire), and health-related quality of life (EuroQol-5 Dimensions). RESULTS: Eighty subjects, 40 in each arm, were randomized. All but two in the sham group completed 10 weekly sessions. There was no significant difference in the proportion of patients experiencing significant (≥ 50%) reduction of anxiety symptoms between the two groups immediately after intervention (32.4% vs 21.6%, P = 0.06) and at 6-week follow-up (25.7% in electroacupuncture vs 27% in sham, P = 0.65). Anxiety, depressive symptom, and bowel symptom severity did not differ significantly between electroacupuncture and sham groups. CONCLUSIONS: Findings failed to support the effectiveness of electroacupuncture for comorbid generalized anxiety disorder and irritable bowel syndrome. Further studies are needed to identify effective acupuncture treatment protocols for such comorbidity.