There is mounting interest in the dual health and environmental benefits of plant-based diets. Such diets prioritise whole foods of plant origin and moderate (though occasionally exclude) animal-sourced foods. However, the evidence base on plant-based diets and health outcomes in Australasia is limited and diverse, making it unsuitable for systematic review. This review aimed to assess the current state of play, identify research gaps, and suggest good practice recommendations. The consulted evidence base included key studies on plant-based diets and cardiometabolic health or mortality outcomes in Australian and New Zealand adults. Most studies were observational, conducted in Australia, published within the last decade, and relied on a single dietary assessment about 10–30 years ago. Plant-based diets were often examined using categories of vegetarianism, intake of plant or animal protein, or dietary indices. Health outcomes included mortality, type 2 diabetes and insulin resistance, obesity, cardiovascular disease, and metabolic syndrome. While Australia has an emerging and generally favourable evidence base on plant-based diets and health outcomes, New Zealand’s evidence base is still nascent. The lack of similar studies hinders the ability to judge the overall certainty of evidence, which could otherwise inform public health policies and strategies without relying on international studies with unconfirmed applicability. The proportional role of plant- and animal-sourced foods in healthy, sustainable diets in Australasia is an underexplored research area with potentially far-reaching implications, especially concerning nutrient adequacy and the combined health and environmental impacts.

Ulcerative Colitis (UC), a type of Inflammatory Bowel Disease (IBD), is a chronic, relapsing gastrointestinal condition with increasing global prevalence. The gut microbiome profile of people living with UC differs from healthy controls and this may play a role in the pathogenesis and clinical management of UC. Probiotics have been shown to induce remission in UC; however, their impact on the gut microbiome and inflammation is less clear. Anthocyanins, a flavonoid subclass, have shown anti-inflammatory and microbiota-modulating properties; however, this evidence is largely preclinical. To explore the combined effect and clinical significance of anthocyanins and a multi-strain probiotic, a 3-month randomised controlled trial will be conducted in 100 adults with UC. Participants will be randomly assigned to one of four groups: anthocyanins (blackcurrant powder) + placebo probiotic, probiotic + placebo fruit powder, anthocyanin + probiotic, or double placebo. The primary outcome is a clinically significant change in the health-related quality-of-life measured with the Inflammatory Bowel Disease Questionnaire-32. Secondary outcomes include shotgun metagenomic sequencing of the faecal microbiota, faecal calprotectin, symptom severity, and mood and cognitive tests. This research will identify the role of adjuvant anti-inflammatory dietary treatments in adults with UC and elucidate the relationship between the gut microbiome and inflammatory biomarkers in this disease, to help identify targeted individualised microbial therapies. ANZCTR registration ACTRN12623000630617.

Dietary guidelines are increasingly promoting mostly plant-based diets, limits on red meat consumption, and plant-based sources of protein for health and environmental reasons. It is unclear how the resulting food substitutions associate with insulin resistance, a risk factor for type 2 diabetes. We modelled the replacement of red and processed meat with plant-based alternatives and the estimated effect on insulin sensitivity. We included 783 participants (55 % female) from the Childhood Determinants of Adult Health study, a population-based cohort of Australians. In adulthood, diet was assessed at three time points using FFQ: 2004–2006, 2009–2011 and 2017–2019. We calculated the average daily intake of each food group in standard serves. Insulin sensitivity was estimated from fasting glucose and insulin concentrations in 2017–2019 (aged 39–49 years) using homoeostasis model assessment. Replacing red meat with a combination of plant-based alternatives was associated with higher insulin sensitivity (β = 10·5 percentage points, 95 % CI (4·1, 17·4)). Adjustment for waist circumference attenuated this association by 61·7 %. Replacing red meat with either legumes, nuts/seeds or wholegrains was likewise associated with higher insulin sensitivity. Point estimates were similar but less precise when replacing processed meat with plant-based alternatives. Our modelling suggests that regularly replacing red meat, and possibly processed meat, with plant-based alternatives may associate with higher insulin sensitivity. Further, abdominal adiposity may be an important mediator in this relationship. Our findings support advice to prioritise plant-based sources of protein at the expense of red meat consumption.

The impact of change in socio-economic status (SES) from childhood to adulthood (SES mobility) on adult diet is not well understood. This study examined associations between three SES mobility variables (area disadvantage, education, occupation) and adult diet quality. 1482 Australian participants reported childhood area-level SES in 1985 (aged 10–15 years) and retrospectively reported highest parental education and main occupation (until participant age 12) and own area-level SES, education, occupation and dietary intake in 2004–2006 (aged 26–36 years). A Dietary Guidelines Index (DGI) was calculated from food frequency and habit questionnaires. A higher score (range 0–100) indicated better diet quality. Sex-stratified linear regression models adjusted for confounders. Area-level SES mobility was not associated with diet quality. Compared with stable high (university) education, stable low (school only) was associated with lower DGI scores (males: β = –5·5, 95 % CI: −8·9, –2·1; females: β = –6·3, 95 % CI: −9·3, –3·4), as was downward educational mobility (participant’s education lower than their parents) (males: β = –5·3, 95 % CI: −8·5, –2·0; females: β = –4·5, 95 % CI: −7·2, –1·7) and stable intermediate (vocational) education among males (β = –3·9, 95 % CI: −7·0, −0·7). Compared with stable high (professional/managerial) occupation, stable low (manual/out of workforce) males (β = –4·9, 95 % CI: −7·6, –2·2), and participants with downward occupation mobility (males: β = –3·2, 95 % CI: −5·3, –1·1; females: β = –2·8, 95 % CI: −4·8, –0·8) had lower DGI scores. In this cohort, intergenerational low education and occupation, and downward educational and occupational mobility, were associated with poor adult diet quality.

Acceptance and commitment therapy (ACT) has substantial support in adult populations but less among adolescents. To date, very little research has evaluated whether it can be delivered in a highly accessible school context. This study examined a 6-hour, weekly ACT-informed school-based group intervention for adolescent girls, focusing on anxiety, depression and building psychological flexibility. Participants (N = 10) who completed the intervention experienced significantly lowered levels of anxiety and increased psychological flexibility, with postintervention scores for all variables trending in the expected directions. Findings provide preliminary support for the efficacy of the intervention and encourages further evaluation of ACT delivered in schools.

Previous research in clinical, community, and school settings has demonstrated positive outcomes for the Secret Agent Society (SAS) social skills training program. This is designed to help children on the autism spectrum become more aware of emotions in themselves and others and to ‘problem-solve’ complex social scenarios. Parents play a key role in the implementation of the SAS program, attending information and support sessions with other parents and providing supervision, rewards, and feedback as their children complete weekly ‘home mission’ assignments. Drawing on data from a school-based evaluation of the SAS program, we examined whether parents’ engagement with these elements of the intervention was linked to the quality of their children’s participation and performance. Sixty-eight 8–14-year-olds (M age = 10.7) with a diagnosis of autism participated in the program. The findings indicated that ratings of parental engagement were positively correlated with children’s competence in completing home missions and with the quality of their contribution during group teaching sessions. However, there was a less consistent relationship between parental engagement and measures of children’s social and emotional skill gains over the course of the program.

In a longitudinal cohort study of young Australian adults, we reported that for women higher baseline levels of fish consumption were associated with reduced incidence of new depressive episodes during the 5-year follow-up. Fish are high in both n-3 fatty acids and tyrosine. In this study, we seek to determine whether n-3 fatty acids or tyrosine explain the observed association. During 2004–2006, a FFQ (nine fish items) was used to estimate weekly fish consumption among 546 women aged 26–36 years. A fasting blood sample was taken and high-throughput NMR spectroscopy was used to measure 233 metabolites, including serum n-3 fatty acids and tyrosine. During 2009–2011, new episodes of depression since baseline were identified using the lifetime version of the Composite International Diagnostic Interview. Relative risks were calculated using log-binomial regression and indirect effects estimated using the STATA binary_mediation command. Potential mediators were added to separate models, and mediation was quantified as the proportion of the total effect due to the mediator. The n-3 DHA mediated 25·3 % of the association between fish consumption and depression when fish consumption was analysed as a continuous variable and 16·6 % when dichotomised (reference group: <2 serves/week). Tyrosine did not mediate the association (<0·1 %). Components in fish other than n-3 fatty acids and tyrosine might be beneficial for women’s mental health.

The aims of the present study were to provide nationally representative data on fruit and vegetable consumption in Vietnam, and to assess the accuracy of the reported numbers of ‘standard servings’ consumed. Data analysed were from a multi-stage stratified cluster survey of 14 706 participants (46·5 % males, response proportion 64·1 %) aged 25−64 years in Vietnam. Measurements were made in accordance with the WHO STEPwise approach to surveillance of non-communicable diseases (STEPS) protocols. Approximately 80 % of Vietnamese people reported having less than five servings of fruit and vegetables daily in a typical week. Fruit and vegetable intake reported in ‘standard serving’ sizes was positively correlated with levels of education completed and household income (P<0·001 for trend). The correlations between summary values for each province reflect some known demographic, geographical and climatic characteristics of the country. For example, provinces at higher latitude had higher mean servings of vegetables (r 0·90), and provinces with higher proportions of urban population had higher mean servings of fruit (r 0·40). In conclusion, about eight in ten Vietnamese people aged 25–64 years did not meet WHO recommendations for daily consumption of at least five servings of fruit and vegetables. On the basis of the consistency of the data collected with other estimates and with physical and demographic characteristics of the country, the WHO STEPS instrument has construct validity for measuring fruit and vegetable intake, but with two issues identified. The issues were seasonal variation in reporting and a limitation on the usefulness of the information for associative analyses.

Eating frequency may be important in the development of overweight and obesity and other cardiometabolic risk factors; however, the evidence is inconsistent. The aim of the present study was to examine the associations between the number of eating occasions and cardiometabolic risk factors in a national population-based sample of young adults. A cohort of 1273 men and 1502 women, aged 26–36 years, completed a meal pattern chart to record when they had eaten during the previous day (in hourly intervals). The total number of eating occasions was calculated. Diet quality was assessed, waist circumference was measured and a fasting blood sample was taken. Dietary intake was compared with the Australian Guide to Healthy Eating. The associations between the number of eating occasions and cardiometabolic risk factors were calculated using linear regression. Analyses were adjusted for age, education and physical activity. Most men ate three to five times per d and most women ate four to six times. The proportion of participants meeting dietary recommendations increased with the number of eating occasions. For men, an additional eating occasion was associated with reductions in mean values for waist circumference ( − 0·75 cm), fasting glucose ( − 0·02 mmol/l), fasting insulin ( − 0·34 mU/l; 2·04 pmol/l), TAG ( − 0·03 mmol/l), total cholesterol ( − 0·08 mmol/l) and LDL-cholesterol ( − 0·06 mmol/l). Adjustment for waist circumference attenuated the results. Significant trends were not observed for women. In conclusion, a higher number of eating occasions were associated with reduced cardiometabolic risk factors in men. Many associations were mediated by waist circumference.