The positive effects of dietary fibre on health are now widely recognised; however, our understanding of the mechanisms involved in producing such benefits remains unclear. There are even uncertainties about how dietary fibre in plant foods should be defined and analysed. This review attempts to clarify the confusion regarding the mechanisms of action of dietary fibre and deals with current knowledge on the wide variety of dietary fibre materials, comprising mainly of NSP that are not digested by enzymes of the gastrointestinal (GI) tract. These non-digestible materials range from intact cell walls of plant tissues to individual polysaccharide solutions often used in mechanistic studies. We discuss how the structure and properties of fibre are affected during food processing and how this can impact on nutrient digestibility. Dietary fibre can have multiple effects on GI function, including GI transit time and increased digesta viscosity, thereby affecting flow and mixing behaviour. Moreover, cell wall encapsulation influences macronutrient digestibility through limited access to digestive enzymes and/or substrate and product release. Moreover, encapsulation of starch can limit the extent of gelatinisation during hydrothermal processing of plant foods. Emphasis is placed on the effects of diverse forms of fibre on rates and extents of starch and lipid digestion, and how it is important that a better understanding of such interactions with respect to the physiology and biochemistry of digestion is needed. In conclusion, we point to areas of further investigation that are expected to contribute to realisation of the full potential of dietary fibre on health and well-being of humans.

Improved social relationships and connectedness is a frequently cited benefit of retirement community living. However, few studies have prospectively investigated changes in loneliness or social networks following relocation. This study involved 83 Australians (aged 57–90 years) relocating to independent living units within a retirement community. A prospective longitudinal design was employed whereby data was collected prior to relocation, and 1, 6 and 12 months post relocation. Comparisons were made with a sample of community-dwelling (N = 549) residents of the same age. Individual characteristics (e.g., personality characteristics) associated with change were also explored. Results indicated reduced loneliness and increased neighbour support networks following relocation. A reduction in contact with friends was also observed. This study provides an important contribution to our understanding of the initial impact of transitioning into a retirement community on personal relationships. Through exploring factors associated with successful transition, we can begin to understand the characteristics of those individuals most likely to thrive in this type of environment.

A number of studies have demonstrated that consuming almonds increases satiety but does not result in weight gain, despite their high energy and lipid content. To understand the mechanism of almond digestion, in the present study, we investigated the bioaccessibility of lipids from masticated almonds during in vitro simulated human digestion, and determined the associated changes in cell-wall composition and cellular microstructure. The influence of processing on lipid release was assessed by using natural raw almonds (NA) and roasted almonds (RA). Masticated samples from four healthy adults (two females, two males) were exposed to a dynamic gastric model of digestion followed by simulated duodenal digestion. Between 7·8 and 11·1 % of the total lipid was released as a result of mastication, with no significant differences between the NA and RA samples. Significant digestion occurred during the in vitro gastric phase (16·4 and 15·9 %) and the in vitro duodenal phase (32·2 and 32·7 %) for the NA and RA samples, respectively. Roasting produced a smaller average particle size distribution post-mastication; however, this was not significant in terms of lipid release. Light microscopy showed major changes that occurred in the distribution of lipid in all cells after the roasting process. Further changes were observed in the surface cells of almond fragments and in fractured cells after exposure to the duodenal environment. Almond cell walls prevented lipid release from intact cells, providing a mechanism for incomplete nutrient absorption in the gut. The composition of almond cell walls was not affected by processing or simulated digestion.

Background: Findings from studies investigating depression in adults in late life are mixed due to a lack of large longitudinal studies with the power necessary to yield reliable estimates of stability or change. We examined the long-term stability of probable depression and depressive symptomology over a 13-year period in the Dynamic Analyses to Optimize Ageing (DYNOPTA) project.

Methods: Community-living participants (N = 35,200) were aged 45–103 at baseline, predominantly female (79%), partnered (73%), and educated to secondary school only (61%) and followed for up to 13 years.

Results: At baseline, increased age was associated with lower prevalence of probable depression and depressive symptomology. Over time, prevalence of probable depression was stable while levels of depressive symptomology reported a small decline. However, this finding was not consistent for all age groups; there was evidence for increasing levels of depressive symptomology, but not probable depression, as individuals aged. This effect was particularly notable among males aged 70 plus years.

Conclusions: These results answer important questions relating to the longitudinal prevalence of probable depression and depressive symptomology in a sample of older Australians. These findings have policy implications for mental health service provision for older adults.

Background: There is considerable debate about the prevalence of depression in old age. Epidemiological surveys and clinical studies indicate mixed evidence for the association between depression and increasing age. We examined the prevalence of probable depression in the middle aged to the oldest old in a project designed specifically to investigate the aging process.

Methods: Community-living participants were drawn from several Australian longitudinal studies of aging that contributed to the Dynamic Analyses to Optimise Ageing (DYNOPTA) project. Different depression scales from the contributing studies were harmonized to create a binary variable that reflected “probable depression” based on existing cut-points for each harmonized scale. Weighted prevalence was benchmarked to the Australian population which could be compared with findings from the 1997 and 2007 National Surveys of Mental Health and Well-Being (NSMHWB).

Results: In the DYNOPTA project, females were more likely to report probable depression. This was consistent across age levels. Both NSMHWB surveys and DYNOPTA did not report a decline in the likelihood of reporting probable depression for the oldest old in comparison with mid-life.

Conclusions: Inconsistency in the reports of late-life depression prevalence in previous epidemiological studies may be explained by either the exclusion and/or limited sampling of the oldest old. DYNOPTA addresses these limitations and the results indicated no change in the likelihood of reporting depression with increasing age. Further research should extend these findings to examine within-person change in a longitudinal context and control for health covariates.

Background. Spousal concordance for common mental disorders provides evidence of the relevance of social contextual factors. There are, however, limitations within the existing literature examining spousal similarity in mental health and little consensus as to the causes of spousal similarity. This study considers a large representative sample and examines an extensive range of risk factors using multilevel statistical methods to explore spousal similarity in common mental disorders.

Method. Data were from the Household, Income and Labour Dynamics in Australia (HILDA) Survey, a large nationally representative survey of Australian households. Analysis focused on 3808 mixed-sex couples in marriage and de facto relationships. Multilevel models assessed the mental health scale of the SF-36. Analyses considered risk factors at the individual, couple and area levels, examined the effects of relationship duration on concordance, and considered longitudinal data to assess the consistency with cross-sectional analysis.

Results. Significant spousal concordance on the mental health scale was demonstrated (r=0·25) and was independent of, and unexplained by mental health risk factors, including experience of multiple shared life events. Spousal similarity for mental health increased across the first 5 years of relationships.

Conclusions. Evidence of spousal concordance for common mental disorders highlights the importance of the social context of marriage in the aetiology of mental illness and identifies an important direction for further research.