Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology

Objective: Individuals with obesity and type 2 diabetes differ from lean and healthy individuals in their abundance of certain gut microbial species and microbial gene richness. Abundance of Akkermansia muciniphila, a mucin-degrading bacterium, has been inversely associated with bodyfat mass and glucose intolerance in mice, but more evidence is needed in humans. The impact of diet and weight loss on this bacterial species is unknown. Our objective was to evaluate the association between fecal A. muciniphila abundance, fecal microbiome gene richness, diet, host characteristics, and their changes after calorie restriction (CR). Design: The intervention consisted of a 6-week CR period followed by a 6-week weight stabilization (WS) diet in overweight and obese adults (N=49, including 41 women). Fecal A. muciniphila abundance, fecal microbial gene richness, diet and bioclinical parameters were measured at baseline and after CR and WS. Results: At baseline A. muciniphila was inversely related to fasting glucose, waist-to-hip ratio, and subcutaneous adipocyte diameter. Subjects with higher gene richness and A. muciniphila abundance exhibited the healthiest metabolic status, particularly in fasting plasma glucose, plasma triglycerides and body fat distribution. Individuals with higher baseline A. muciniphila displayed greater improvement in insulin sensitivity markers and other clinical parameters after CR. A. muciniphila was associated with microbial species known to be related to health. Conclusion: A. muciniphila is associated with a healthier metabolic status and better clinicaloutcomes after CR in overweight/obese adults, however the interaction between gut microbiota ecology and A. muciniphila has to be taken into account.

Adulteration and Poor Quality of Ginkgo biloba Supplements

Adulteration of Ginkgo products sold as unregistered supplements within the very large market of Ginkgo products (reputedly £650 million annually) through the post-extraction addition of cheaper (e.g. buckwheat derived) rutin is suspected to allow sub-standard products to appear satisfactory to third parties, e.g. secondary buyers along the value chain or any regulatory authorities. This study was therefore carried out to identify products that did not conform to their label specification and may have been actively adulterated to enable access to the global markets. 500 MHz Bruker NMR spectroscopy instrumentation combined with Topspin version 3.2 and a CAMAG HPTLC system (HPTLC Association for the analysis of Ginkgo biloba leaf) were used to generate NMR spectra (focusing on the 6–8 ppm region for analysis) and chromatograms, respectively. Out of the 35 samples of Ginkgo biloba analysed, 33 were found to contain elevated levels of rutin and/or quercetin, or low levels of Ginkgo metabolites when compared with the reference samples. Samples with disproportional levels of rutin or quercetin compared with other gingko metabolites are likely to be adulterated, either by accident or intentionally, and those samples with low or non-existent gingko metabolite content may have been produced using poor extraction techniques. Only two of the investigated samples were found to match with the High-Performance Thin-Layer Chromatography (HPTLC) fingerprint of the selected reference material. All others deviated significantly. One product contained a 5-hydroxytryptophan derivative, which is not a natural constituent of Ginkgo biloba. Overall, these examples either suggest a poor extraction technique or deliberate adulteration along the value chain. Investigating the ratio of different flavonoids e.g. quercetin and kaempferol using NMR spectroscopy and HPTLC will provide further evidence as to the degree and kind of adulteration of Gingko supplements. From a consumer perspective the equivalence in identity and overall quality of the products needs to be guaranteed for supplements too and not only for products produced according to a quality standard or pharmacopoeial monograph.