Short-term high-calorie high-fat feeding induces hyperinsulinemia and blunts skeletal muscle microvascular blood flow in healthy humans.

Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal. It is not known whether this occurs in humans. We investigated the temporal impact of a 7-day high-calorie high-fat (HCHF) diet intervention (+52% kJ; 41% fat) on fasting and postprandial cardiometabolic outcomes in 14 healthy adults (18-37 yr). Metabolic health and vascular responses to a mixed-meal challenge (MMC) were measured at pre (day 0)-, mid (day 4)- and post (day 8)-intervention. There were no significant differences in body weight, body fat %, fasting blood glucose, and fasting plasma insulin concentrations at pre-, mid- and postintervention. Compared with preintervention there was a significant increase in insulin (but not glucose) total area under the curve in response to the MMC at midintervention (P = 0.041) and at postintervention (P = 0.028). Unlike at pre- and midintervention, at postintervention muscle MBF decreased at 60 min (P = 0.024) and 120 min (P = 0.023) after the MMC. However, macrovascular blood flow was significantly increased from 0 to 60 min (P < 0.001) and 120 min (P < 0.001) after the MMC at pre-, mid- and postintervention. Therefore, short-term HCHF feeding in healthy individuals leads to elevated postprandial insulin but not glucose levels and a blunting of meal-induced skeletal muscle MBF responses but not macrovascular blood flow responses.NEW & NOTEWORTHY This is the first study to investigate skeletal muscle microvascular blood flow (MBF) responses in humans after short-term high-calorie high-fat (HCHF) diet. The main findings were that HCHF diet causes elevated postprandial insulin in healthy individuals within 3 days and blunts meal-induced muscle MBF within 7 days, despite no impairments in postprandial glucose or macrovascular blood flow.

Different Sources of Fiber Intake and Risk of 17 Specific Cancers and All Cancers Combined: Prospective Study of 364,856 Participants in the UK Biobank.

Inverse associations between dietary fiber (DF) and colorectal cancer risk are well-established. However, evidence is limited in relation to other cancer sites. This study, of 364,856 participants from the UK Biobank, aimed to evaluate the associations between total and source-specific partial DF and risk of 17 specific cancers and all cancers combined. Partial DF was derived from baseline touchscreen questionnaire data on cereal, bread, fruit, and vegetable intake. The outcomes were incident cancer at 17 sites and all cancers combined. Cox proportional hazards models were applied. Over a median 8.8-year follow-up period, 30,725 people were diagnosed with cancer. After adjusting for sociodemographic and lifestyle factors, those in the highest quintile of partial DF compared with the lowest quintile (<9.6 vs ≥19.1 g/day) had 10% lower risk of cancer overall, with the greatest risk reductions observed for cervical (hazard ratio (HR) = 0.33, 95% confidence interval (CI): 0.14; 0.82), esophageal (HR = 0.66, 95% CI: 0.52; 0.84), lung (HR = 0.67, 95% CI: 0.59; 0.76), bladder (HR = 0.72, 95% CI: 0.56; 0.91), and kidney (HR = 0.75, 95% CI: 0.61; 0.92) cancers. Associations between DF and lung cancer were observed only in current and former smokers. Higher DF intake, in particular cereal fiber and fruit and vegetable fiber, was associated with a lower risk of overall and multiple site-specific cancers.

Modeling the Impact of Substituting Meat and Dairy Products with Plant-Based Alternatives on Nutrient Adequacy and Diet Quality.

BACKGROUND: Novel plant-based meat and dairy alternatives are designed to mimic and replace animal-sourced products, yet their nutritional composition differs from traditional alternatives such as legumes and beans. The nutritional impacts of switching from animal-sourced to traditional or novel plant-based alternatives remains unclear. OBJECTIVES: This study aimed to model the impact of partial and complete substitution of animal-sourced meat and dairy products with traditional or novel plant-based alternatives on diet quality and nutrient adequacy in a nationally representative sample of Australian adults. METHODS: Dietary data (1 24-h recall) from the Australian Health Survey 2011-2013 (n = 9115; ≥19 y) were analyzed. Four models simulated partial or complete substitution of animal-sourced meat and dairy with traditional or novel plant-based alternatives. Diet quality was assessed using the Dietary Guideline Index (DGI), and nutrient adequacy was determined using age- and sex-specific nutrient reference values. Modeled diets were compared to a baseline diet using survey-weighted paired t tests. RESULTS: DGI scores improved by 0.3% to 6.0% for all models across all sex and age groups compared to baseline. Improvements in diet quality were greatest for the complete substitution to traditional alternatives (5.1% average increase in DGI). Overall, inclusion of plant-based alternatives (complete or partial) decreased saturated fat and increased dietary fiber. Long-chain n-3 polyunsaturated fatty acids decreased to below adequate intakes for all complete substitution models. Substitution with traditional alternatives decreased sodium and increased calcium, whereas substitution with novel alternatives increased sodium and decreased calcium. CONCLUSIONS: All models using traditional alternatives, and the partial substitution using novel alternatives, showed small but statistically significant improvements in diet quality. Nutrient adequacy varied between models, with nutrients including saturated fat, sodium, calcium, and long-chain fatty acids implicated. Findings highlight the importance of informed choices when switching to traditional or novel plant-based alternatives to prevent suboptimal dietary intake.

Association of five diet scores with severe NAFLD incidence: A prospective study from UK Biobank.

AIM: This study aimed to contrast the associations of five common diet scores with severe non-alcoholic fatty liver disease (NAFLD) incidence. MATERIALS AND METHODS: In total, 162 999 UK Biobank participants were included in this prospective population-based study. Five international diet scores were included: the 14-Item Mediterranean Diet Adherence Screener (MEDAS-14), the Recommended Food Score (RFS), the Healthy Diet Indicator (HDI), the Mediterranean Diet Score and the Mediterranean-DASH Intervention for Neurodegenerative Delay score. As each score has different measurements and scales, all scores were standardized and categorized into quartiles. Cox proportional hazard models adjusted for confounder factors investigated associations between the standardized quartiles and severe NAFLD incidence. RESULTS: Over a median follow-up of 10.2 years, 1370 participants were diagnosed with severe NAFLD. When the analyses were fully adjusted, participants in quartile 4 using the MEDAS-14 and RFS scores, as well as those in quartiles 2 and 3 using the HDI score, had a significantly lower risk of severe incident NAFLD compared with those in quartile 1. The lowest risk was observed in quartile 4 for the MEDAS-14 score [hazard ratio (HR): 0.76 (95% confidence interval (CI): 0.62-0.94)] and the RFS score [HR: 0.82 (95% CI: 0.69-0.96)] and as well as in quartile 2 in the HDI score [HR: 0.80 (95% CI: 0.70-0.91)]. CONCLUSION: MEDAS-14, RFS and HDI scores were the strongest diet score predictors of severe NAFLD. A healthy diet might protect against NAFLD development irrespective of the specific approach used to assess diet. However, following these score recommendations could represent optimal dietary approaches to mitigate NAFLD risk.

Achieving high diet quality at eating occasions: findings from a nationally representative study of Australian adults.

This study examined differences in food groups consumed at eating occasions by the level of adherence to dietary guidelines in Australian adults (≤19 years) and whether consumption differed with respect to age, sex and education levels. Secondary analysis of the 2011-2012 National Nutrition and Physical Activity Survey (n 9054) was performed, using one 24-h dietary recall with self-reported eating occasions. Dietary Guideline Index scores were used to assess adherence to the 2013 Australian Dietary Guidelines. Mean differences (95 % CI) in servings of the five food groups and discretionary foods at eating occasions were estimated for adults with higher and lower diet quality, stratified by sex, age group and education. Using survey-based t-tests, differences of at least half a serving with P values < 0·05 were considered meaningful. Compared with adults with lower diet quality, women and men aged 19-50 years with higher diet quality consumed more serves of vegetables at dinner (mean difference (95 % CI), women; 1·0; 95 % CI (0·7, 1·2); men: 0·9; 95 % CI (0·6, 1·3)) and fewer serves of discretionary foods at snacks (women: -0·7; 95 % CI (-0·9, -0·5); men: -1·0; 95 % CI (-1·4, -0·7). Other food groups, such as grains, dairy products and alternatives, meats and alternatives, were not significantly different between adults with lower and higher diet quality, across any eating occasions and age groups. Discretionary food intake at lunch, dinner and snacks was consistently greater among adults with lower diet quality, regardless of education level. Our findings identify dinner and snacks as opportunities to increase vegetable intake and reduce discretionary food intake, respectively.

Maternal diet quality trajectories from pregnancy to 3.5 years postpartum and associated maternal factors.

PURPOSE: This study examined maternal diet quality trajectories from pregnancy to 3.5 years postpartum and associated maternal factors. METHODS: Data of 473 Australian women from the Healthy Beginnings Trial were used. A food frequency questionnaire collected dietary intake in pregnancy and 1, 2 and 3.5 years postpartum. Diet quality scores were calculated using the 2013 Dietary Guideline Index (DGI-2013) and RESIDential Environments Guideline Index (RDGI). Group-based trajectory modelling identified diet quality trajectories from pregnancy to 3.5 years postpartum. Multivariable logistic regression investigated factors associated with maternal diet quality trajectories. RESULTS: Two stable trajectories of low or high diet quality were identified for the DGI-2013 and RDGI. Women who smoked had higher odds of following the low versus the high DGI-2013 (OR 1.77; 95%CI 1.15, 2.75) and RDGI (OR 1.80; 95%CI 1.17, 2.78) trajectories, respectively. Women who attended university had lower odds of following the low versus the high DGI-2013 (OR 0.41; 95%CI 0.22, 0.76) and RDGI (OR 0.38; 95%CI 0.21, 0.70) trajectories, respectively. Women who were married had lower odds of following the low versus the high DGI-2013 trajectory (OR 0.39; 95%CI 0.17, 0.89), and women who were unemployed had higher odds of following the low versus the high RDGI trajectory (OR 1.78; 95%CI 1.13, 2.78). Maternal age, country of birth, household composition and pre-pregnancy body mass index were not associated with diet quality trajectories. CONCLUSION: Maternal diet quality trajectories remained stable from pregnancy to 3.5 years postpartum. Women who smoked, completed high school or less, were not married or were unemployed tended to follow low, stable diet quality trajectories.

Identifying the barriers and facilitators to fruit and vegetable consumption in rural Australian adults: a mixed methods analysis.

BACKGROUND: Low fruit and vegetable consumption is a leading contributor to non-communicable disease risk. However, understanding of barriers and facilitators to fruit and vegetable intake in rural settings is limited. This study used a mixed methods approach to determine the barriers and facilitators to increasing fruit and vegetable intake in rural Australian adults and to identify if these varied by gender. METHODS: Quantitative and qualitative data were used from the 2019 Active Living Census, completed by adults living in north-west Victoria, Australia. Data were collected on fruit and vegetable intakes and barriers and facilitators to meeting fruit and vegetable recommendations. Multivariate logistic regression analyses were used to investigate the association between facilitators, classified using the socio-ecological framework, and meeting recommendations. Machine learning was used to automate content analysis of open ended information on barriers. RESULTS: A total of 13,464 adults were included in the quantitative analysis (51% female; mean age 48 [SE 0.17] years) with 48% and 19% of participants consuming the recommended two serves of fruit and five serves of vegetables daily, respectively. Strongest facilitators to fruit consumption were at the individual level: never smoked (OR: 2.12 95% CI: 1.83-2.45) and not drinking alcohol (OR: 1.47 95% CI: 1.31-1.64). Strongest facilitators for vegetable consumption were found at all levels; i.e., individual level: used to smoke (OR: 1.48 95% CI: 1.21-1.80), social-environmental level: living with three or more people (OR: 1.41 95% CI: 1.22-1.63), and physical-environmental level: use community gardens (OR: 1.20 95% CI: 1.07-1.34). Qualitative analyses (fruit n = 5,919; vegetable n = 9,601) showed that barriers to fruit consumption included a preference for other snacks and desire to limit sugar content, whilst lack of time and unachievable guidelines were barriers for vegetables. Barriers and facilitators differed by gender; females experienced barriers due to having a more varied diet while males reported a dislike of the taste. CONCLUSIONS: Barriers and facilitators to fruit and vegetable consumption among rural Australian adults were identified across all levels of the socio-ecological framework and varied between fruit and vegetables and by gender. Strategies that address individual, social, and physical-level barriers are required to improve consumption.

Do food-related capabilities, opportunities and motivations of adolescents mediate the association between socioeconomic position in adolescence and diet quality in early adulthood?

BACKGROUND: Socio-economic position (SEP) in adolescence may influence diet quality over the life course. However, knowledge of whether individual and environmental determinants of diet quality mediate the longitudinal association between SEP and diet quality is limited. This study examined whether and to what extent food-related capabilities, opportunities and motivations of adolescents mediated the longitudinal association between SEP in adolescence and diet quality in early adulthood overall and by sex. METHODS: Longitudinal data (annual surveys) from 774 adolescents (16.9 years at baseline; 76% female) from ProjectADAPT (T1 (baseline), T2, T3) were used. SEP in adolescence (T1) was operationalized as highest level of parental education and area-level disadvantage (based on postcode). The Capabilities, Opportunities and Motivations for Behaviour (COM-B) model was used as a framework to inform the analysis. Determinants in adolescence (T2) included food-related activities and skills (Capability), home availability of fruit and vegetables (Opportunity) and self-efficacy (Motivation). Diet quality in early adulthood (T3) was calculated using a modified version of the Australian Dietary Guidelines Index based on brief dietary questions on intake of foods from eight food groups. Structural equation modelling was used to estimate the mediating effects of adolescents' COM-B in associations between adolescent SEP and diet quality in early adulthood overall and by sex. Standardized beta coefficients (ß) and robust 95% confidence intervals (CI) were generated, adjusted for confounders (T1 age, sex, diet quality, whether still at school, and living at home) and clustering by school. RESULTS: There was evidence of an indirect effect of area-level disadvantage on diet quality via Opportunity (ß: 0.021; 95% CI: 0.003 to 0.038), but limited evidence for parental education (ß: 0.018; 95% CI: -0.003 to 0.039). Opportunity mediated 60.9% of the association between area-level disadvantage and diet quality. There was no evidence of an indirect effect via Capability or Motivation for either area-level disadvantage or parental education, or in males and females separately. CONCLUSIONS: Using the COM-B model, the home availability of fruit and vegetables (Opportunity) of adolescents explained a large proportion of the association between area-level disadvantage in adolescence and diet quality in early adulthood. Interventions to address poor diet quality among adolescents with a lower SEP should prioritize environmental determinants of diet quality.

Digital behaviour change interventions to increase vegetable intake in adults: a systematic review.

BACKGROUND: Digital interventions may help address low vegetable intake in adults, however there is limited understanding of the features that make them effective. We systematically reviewed digital interventions to increase vegetable intake to 1) describe the effectiveness of the interventions; 2) examine links between effectiveness and use of co-design, personalisation, behavioural theories, and/or a policy framework; and 3) identify other features that contribute to effectiveness. METHODS: A systematic search strategy was used to identify eligible studies from MEDLINE, Embase, PsycINFO, Scopus, CINAHL, Cochrane Library, INFORMIT, IEEE Xplore and Clinical Trial Registries, published between January 2000 and August 2022. Digital interventions to increase vegetable intake were included, with effective interventions identified based on statistically significant improvement in vegetable intake. To identify policy-action gaps, studies were mapped across the three domains of the NOURISHING framework (i.e., behaviour change communication, food environment, and food system). Risk of bias was assessed using Cochrane tools for randomized, cluster randomized and non-randomized trials. RESULTS: Of the 1,347 records identified, 30 studies were included. Risk of bias was high or serious in most studies (n = 25/30; 83%). Approximately one quarter of the included interventions (n = 8) were effective at improving vegetable intake. While the features of effective and ineffective interventions were similar, embedding of behaviour change theories (89% vs 61%) and inclusion of stakeholders in the design of the intervention (50% vs 38%) were more common among effective interventions. Only one (ineffective) intervention used true co-design. Although fewer effective interventions included personalisation (67% vs 81%), the degree of personalisation varied considerably between studies. All interventions mapped across the NOURISHING framework behaviour change communication domain, with one ineffective intervention also mapping across the food environment domain. CONCLUSION: Few digital interventions identified in this review were effective for increasing vegetable intake. Embedding behaviour change theories and involving stakeholders in intervention design may increase the likelihood of success. The under-utilisation of comprehensive co-design methods presents an opportunity to ensure that personalisation approaches better meet the needs of target populations. Moreover, future digital interventions should address both behaviour change and food environment influences on vegetable intake.

Prospective associations between diet quality and health-related quality of life in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study.

Changes between diet quality and health-related quality of life (HR-QoL) over 12 years were examined in men and women, in 2844 adults (46 % males; mean age 47·3 (sd 9·7) years) from the Australian Diabetes, Obesity and Lifestyle study with data at baseline, 5 and 12 years. Dietary intake was assessed with a seventy-four-item FFQ. Diet quality was estimated with the Dietary Guideline Index, Mediterranean-Dietary Approaches to Stop Hypertension Diet Intervention for Neurological Delay Index (MIND) and Dietary Inflammatory Index. HR-QoL in terms of global, physical component summary (PCS) and mental component summary (MCS) was assessed with the Short-Form Health Survey-36. Fixed effects regression models adjusted for confounders were performed. Mean MCS increased from baseline (49·0, sd 9·3) to year 12 (50·7, sd 9·1), whereas mean PCS decreased from baseline (51·7, sd 7·4) to year 12 (49·5, sd 8·6). For the total sample, an improvement in MIND was associated with an improvement in global QoL (ß = 0·28, 95 % CI (0·007, 0·55)). In men, an improvement in MIND was associated with an improvement in global QoL (ß = 0·28, 95 % CI (0·0004, 0·55)). In women, improvement in MIND was associated with improvements in global QoL (ß = 0·62 95 % CI (0·38, 0·85)), MCS (ß = 0·75, 95 % CI (0·29, 1·22)) and PCS (ß = 0·75, 95 % CI (0·29, 1·22)). Positive changes in diet quality were associated with broad improvements in HR-QoL, and most benefits were observed in women when compared to men. These findings support the need for strategies to assist the population in consuming healthy dietary patterns to lead to improvements in HR-QoL.