Bacteria of the Human Gut Microbiome Catabolize Red Seaweed Glycans With Carbohydrate-Active Enzyme Updates From Extrinsic Microbes.

Bacteria of the human gut microbiome catabolize red seaweed glycans with carbohydrate-active enzyme updates from extrinsic microbes.

Filed under: Eating Disorders

Proc Natl Acad Sci U S A. 2012 Nov 12;
Hehemann JH, Kelly AG, Pudlo NA, Martens EC, Boraston AB

Humans host an intestinal population of microbes-collectively referred to as the gut microbiome-which encode the carbohydrate active enzymes, or CAZymes, that are absent from the human genome. These CAZymes help to extract energy from recalcitrant polysaccharides. The question then arises as to if and how the microbiome adapts to new carbohydrate sources when modern humans change eating habits. Recent metagenome analysis of microbiomes from healthy American, Japanese, and Spanish populations identified putative CAZymes obtained by horizontal gene transfer from marine bacteria, which suggested that human gut bacteria evolved to degrade algal carbohydrates-for example, consumed in form of sushi. We approached this hypothesis by studying such a polysaccharide utilization locus (PUL) obtained by horizontal gene transfer by the gut bacterium Bacteroides plebeius. Transcriptomic and growth experiments revealed that the PUL responds to the polysaccharide porphyran from red algae, enabling growth on this carbohydrate but not related substrates like agarose and carrageenan. The X-ray crystallographic and biochemical analysis of two proteins encoded by this PUL, BACPLE_01689 and BACPLE_01693, showed that they are ?-porphyranases belonging to glycoside hydrolase families 16 and 86, respectively. The product complex of the GH86 at 1.3 Å resolution highlights the molecular details of porphyran hydrolysis by this new porphyranase. Combined, these data establish experimental support for the argument that CAZymes and associated genes obtained from extrinsic microbes add new catabolic functions to the human gut microbiome.
HubMed – eating


Physical Activity and Blood Pressure in Primary School Children: A Longitudinal Study.

Filed under: Eating Disorders

Hypertension. 2012 Nov 12;
Knowles G, Pallan M, Thomas GN, Ekelund U, Cheng KK, Barrett T, Adab P

High blood pressure (BP) is becoming increasingly common during childhood. Regular physical activity (PA) reduces BP in adults, but limited studies have reported inconsistent results among children. The aim of this study is to examine, for the first time, the cross-sectional and longitudinal associations between BP and objectively measured PA in young children of predominantly South Asian background. Data from the Birmingham healthy Eating and Active lifestyle for CHildren Study were analyzed. Five hundred seventy-four children, aged 5 to 7 years, underwent a series of measures at baseline and were followed up 2 years later. PA was objectively measured using accelerometry and converted to counts per minute (total PA, cpm), and time spent in moderate-vigorous PA (minutes per day). BP was measured by trained staff using standard protocols. Data were available for 512 children at baseline (mean age 6.5 years, range 5.4-7.8 years), and 427 of these children were followed up. Baseline total PA was inversely associated with diastolic BP at both baseline (adjusted regression coefficient: -0.75 mm Hg [95% CI -1.33 to -0.18] per 20 cpm) and follow-up (-0.74 mm Hg [95% CI -1.40 to -0.08]). All associations remained unchanged after further adjustment for weight status. This study strengthens evidence of a causal association between higher PA and lower BP in children as young as 5, independent of weight status. The results provide support for development of interventions to increase PA in young children.
HubMed – eating


What can qualitative studies tell us about the experiences of women who are pregnant that have an eating disorder?

Filed under: Eating Disorders

Midwifery. 2012 Nov 10;
Tierney S, McGlone C, Furber C

OBJECTIVE: pregnancy is a life-stage during which women undergo significant changes to their body and can feel acute responsibility for the development and well-being of the fetus. A synthesis of qualitative studies was conducted to increase our understanding of pregnancy experiences among women with an eating disorder. DESIGN: a systematic search of eight electronic databases was carried out to identify relevant investigations. Studies were appraised by two authors. Data were combined using framework analysis. From 459 references, seven papers were included in the review. FINDINGS: an overriding concept of inner turmoil transpired from the synthesis. This personal conflict related to the fear and guilt expressed by interviewees and stemmed from their association of self-worth with their body, concerns about their child’s health and worries about others’ response to their eating and weight control practices. KEY CONCLUSIONS: participants reported vacillating between wanting to do the best for their child, being motivated by social pressures and feeling the need to control their body for self-preservation purposes. This created the inner turmoil they experienced while pregnant. IMPLICATIONS FOR PRACTICE: midwives should be sensitive to the possibility of an eating disorder among pregnant women. In such cases, practitioners could act as a conduit for any assistance required, guiding these mothers towards appropriate nutritional and psychological support. To do this, professionals must have knowledge of such conditions and be aware of services available for women disclosing disordered eating behaviours.
HubMed – eating


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