Impact of ß2-1 fructan on faecal community change: results from a placebo-controlled, randomised, double-blinded, cross-over study in healthy adults.

Healthy adults (n 30) participated in a placebo-controlled, randomised, double-blinded, cross-over study consisting of two 28 d treatments (ß2-1 fructan or maltodextrin; 3×5 g/d) separated by a 14-d washout. Subjects provided 1 d faecal collections at days 0 and 28 of each treatment. The ability of faecal bacteria to metabolise ß2-1 fructan was common; eighty-seven species (thirty genera, and four phyla) were isolated using anaerobic medium containing ß2-1 fructan as the sole carbohydrate source. ß2-1 fructan altered the faecal community as determined through analysis of terminal restriction fragment length polymorphisms and 16S rRNA genes. Supplementation with ß2-1 fructan reduced faecal community richness, and two patterns of community change were observed. In most subjects, ß2-1 fructan reduced the content of phylotypes aligning within the Bacteroides, whereas increasing those aligning within bifidobacteria, Faecalibacterium and the family Lachnospiraceae. In the remaining subjects, supplementation increased the abundance of Bacteroidetes and to a lesser extent bifidobacteria, accompanied by decreases within the Faecalibacterium and family Lachnospiraceae. ß2-1 Fructan had no impact on the metagenome or glycoside hydrolase profiles in faeces from four subjects. Few relationships were found between the faecal bacterial community and various host parameters; Bacteroidetes content correlated with faecal propionate, subjects whose faecal community contained higher Bacteroidetes produced more caproic acid independent of treatment, and subjects having lower faecal Bacteroidetes exhibited increased concentrations of serum lipopolysaccharide and lipopolysaccharide binding protein independent of treatment. We found no evidence to support a defined health benefit for the use of ß2-1 fructans in healthy subjects.

An Analysis of Factors Associated with 25-Hydroxyvitamin D Levels in White and Non-White Canadians.

Vitamin D status was assessed in 19-79 year old whites (8351 participants of European ancestry) and non-whites (1840 participants encompassing all other ancestries) from cycles 1 to 3 (years 2007-2013) of the Canadian Health Measures Survey. Status was assessed using the U.S. Institute of Medicine (IOM) 25-hydroxyvitamin D [25(OH)D] cut point values of 30 and 40 nmol/L. Overall, median 25(OH)D concentrations were significantly higher in whites [58.9 (28.6, 100.1) nmol/L; 5th and 95th percentile] compared with non-whites [43.5 (19.0, 83.2); P < 0.001]. Values were higher in females [58.5 (27.5, 101.3) nmol/L] when compared with males [53.5 (24.2, 92.7) nmol/L] and increased with age. Non-whites were more likely to have 25(OH)D values below IOM established cut points for optimum bone health with 20.1 (16.0, 24.2) and 42.2% (36.8, 47.7) of non-whites having serum 25(OH)D concentrations <30 and <40 nmol/L, respectively. The corresponding values for whites were 5.9 (4.6, 7.2) and 16.1% (14.0, 18.3). Values were lower during the first quarter when compared with the third quarter. Supplement intake was an important factor in determining 25(OH)D levels, but it did not alone account for the difference in status. Equivalent increases in 25(OH)D levels were observed in whites and non-whites during the summer months, suggesting there was no functional difference in sun exposure response. It is apparent that a complex interaction of factors affect 25(OH)D values in free-living Canadians.