Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolism.

OBJECTIVES: Gut microbiota is a key component in obesity and type 2 diabetes, yet mechanisms and metabolites central to this interaction remain unclear. We examined the human gut microbiome's functional composition in healthy metabolic state and the most severe states of obesity and type 2 diabetes within the MetaCardis cohort. We focused on the role of B vitamins and B7/B8 biotin for regulation of host metabolic state, as these vitamins influence both microbial function and host metabolism and inflammation. DESIGN: We performed metagenomic analyses in 1545 subjects from the MetaCardis cohorts and different murine experiments, including germ-free and antibiotic treated animals, faecal microbiota transfer, bariatric surgery and supplementation with biotin and prebiotics in mice. RESULTS: Severe obesity is associated with an absolute deficiency in bacterial biotin producers and transporters, whose abundances correlate with host metabolic and inflammatory phenotypes. We found suboptimal circulating biotin levels in severe obesity and altered expression of biotin-associated genes in human adipose tissue. In mice, the absence or depletion of gut microbiota by antibiotics confirmed the microbial contribution to host biotin levels. Bariatric surgery, which improves metabolism and inflammation, associates with increased bacterial biotin producers and improved host systemic biotin in humans and mice. Finally, supplementing high-fat diet-fed mice with fructo-oligosaccharides and biotin improves not only the microbiome diversity, but also the potential of bacterial production of biotin and B vitamins, while limiting weight gain and glycaemic deterioration. CONCLUSION: Strategies combining biotin and prebiotic supplementation could help prevent the deterioration of metabolic states in severe obesity. TRIAL REGISTRATION NUMBER: NCT02059538.

Association of diet quality and physical activity with healthy ageing in the French NutriNet-Santé cohort.

A growing number of studies have explored overall health during ageing in a holistic manner by investigating multidimensional models of healthy ageing (HA). However, little attention has been given to the role of adherence to national nutrition guidelines in that context. This study aimed to investigate the prospective association between adherence to the French nutrition guidelines and HA. The authors analysed data from 21 407 participants of the NutriNet-Santé study with a median baseline age of 55·6 years (2009-2014) and initially free of major chronic diseases. HA was defined as not developing major chronic disease, no depressive symptoms, no function-limiting pain, independence in instrumental activities of daily living, good physical, cognitive and social functioning, as well as good self-perceived health. Adherence to guidelines of the French Nutrition and Health Programme (Programme National Nutrition Santé or PNNS) was measured via the PNNS Guideline Score (PNNS-GS), using baseline data from repeated 24-h dietary records and physical activity questionnaires. After a median follow-up of 5·7 years, 46·3 % of participants met our HA criteria. Robust-error-variance Poisson regression revealed that higher PNNS-GS scores, reflecting higher adherence to nutrition recommendations (including both diet and physical activity guidelines), were associated with a higher probability to age healthily (relative riskquartile 4 v. quartile 1 = 1·17 (95 % CI 1·12, 1·22)). Supplementary analyses revealed that this association may, to a small part, be mediated by weight status. The results suggest that high adherence to the French national nutrition recommendations may be linked to better overall health throughout ageing.

Are self-reported unhealthy food choices associated with an increased risk of breast cancer? Prospective cohort study using the British Food Standards Agency nutrient profiling system.

OBJECTIVES: French authorities are considering the implementation of a simplified nutrition labelling system on food products to help consumers make healthier food choices. One of the most documented candidates (Five-Colour Nutrition Label/Nutri-score) is based on the British Food Standards Agency Nutrient Profiling System (FSA-NPS), a score calculated for each food/beverage using the 100 g amount of energy, sugar, saturated fatty acid, sodium, fibres, proteins, and fruits and vegetables. To assess its potential public health relevance, studies were conducted on the association between the nutritional quality of the diet, measured at the individual level by an energy-weighted mean of all FSA-NPS scores of foods usually consumed (FSA-NPS dietary index (FSA-NPS DI)), and the risk of chronic diseases. The present study aimed at investigating the relationship between the FSA-NPS DI and breast cancer risk. DESIGN: Prospective study. SETTING: Population based, NutriNet-Santé cohort, France. PARTICIPANTS: 46 864 women aged ≥35 years who completed ≥3 24-hour dietary records during their first 2 year of follow-up. PRIMARY OUTCOME MEASURE: Associations between FSA-NPS DI and breast cancer risk (555 incident breast cancers diagnosed between 2009 and 2015) were characterised by multivariable-adjusted Cox proportional hazard models. RESULTS: A higher FSA-NPS DI (lower nutritional quality of the diet) was associated with an increased breast cancer risk (HR1-point increment=1.06 (1.02-1.11), p=0.005; HRQ5vs.Q1=1.52 (1.11-2.08), p trend=0.002). Similar trends were observed in premenopausal and postmenopausal women (HR1-point increment=1.09 (1.01-1.18) and 1.05 (1.00-1.11), respectively).This study was based on an observational cohort using self-reported dietary data, thus residual confounding cannot be entirely ruled out. Finally, this holistic approach does not allow investigating which factors in the diet most specifically influence breast cancer risk. CONCLUSIONS: These results suggested that unhealthy food choices, as characterised by the FSA-NPS, may be associated with an increase in breast cancer risk, supporting the potential public health relevance of using this profiling system in the framework of public health nutritional measures.