Dr Erin Clarke

Background/Objectives: Thus far, no studies have examined the relationship between fruit and vegetable (F and V) intake, urinary metabolite quantities, and weight change. Therefore, the aim of the current study was to explore changes in urinary metabolomic profiles during and after a 10-week weight loss intervention where participants were prescribed a high F and V diet (7 servings daily). Methods: Adults with overweight and obesity (n = 34) received medical nutrition therapy counselling to increase their F and V intakes to national targets (7 servings a day). Data collection included weight, dietary intake, and urine samples at baseline at week 2 and week 10. Urinary metabolite profiles were quantified using 1H NMR spectroscopy. Machine learning statistical approaches were employed to identify novel urine-based metabolite biomarkers associated with high F and V diet patterns at weeks 2 and 10. Metabolic changes appearing in urine in response to diet were quantified using Metabolite Set Enrichment Analysis (MSEA). Results: Energy intake was significantly lower (p = 0.02) at week 10 compared with baseline. Total F and V intake was significantly higher at week 2 and week 10 (p < 0.05). In total, 123 urinary metabolites were quantified. At week 10, 21 metabolites showed significant changes relative to baseline. Of these, 11 metabolites also significantly changed at week 2. These overlapping metabolites were acetic acid, dimethylamine, choline, fumaric acid, glutamic acid, L-tyrosine, histidine, succinic acid, uracil, histamine, and 2-hydroxyglutarate. Ridge Classifier and Linear Discriminant Analysis provided best prediction accuracy values of 0.96 when metabolite level of baseline was compared to week 10. Conclusions: Urinary metabolites quantified represent potential candidate biomarkers of high F and V intake, associated with a reduction in energy intake. Further studies are needed to validate these findings in larger population studies.

Determine how healthcare professionals perceive their role in nutrition assessment and management, and explore barriers and enablers to assessment and management of nutrition in individuals with DFU. Mixed methods including a cross-sectional online survey derived from current international guidelines and theoretical domains framework, and semi-structured interviews with conventional content analysis was performed. One hundred and ninety-one participants completed the survey, with 19 participating in interviews. Many health professionals are not confident in their ability in this area of practice, are uncertain their nutrition advice or management will be effective in assisting wound healing outcomes and are uncertain their intervention would result in adequate behaviour change by the individual with DFU. Major barriers to implementation of nutrition assessment and management were: inadequate time, lack of knowledge and lack of clinical guidance and enablers were as follows: professional development, a standardised clinical pathway and screening tool and a resource addressing wound healing and diabetes management. Nutrition assessment and management in individuals with DFU is not consistently applied. Whilst health professionals believed nutrition was important for wound healing, they lacked confidence in implementing into their practice. Further dissemination of existing guidance and implementation of education programs and resources would help overcome cited barriers.

Double-blind, placebo-controlled, randomized controlled trials are the gold standard for clinical trials in nutrition science. For trials of whole diets, dietary counseling is advantageous as they offer clinical translatability although can vary in the fidelity of the intended intervention from participant to participant and across studies. Feeding trials, in which most or all food is provided, offer high precision and can provide proof-of-concept evidence that a dietary intervention is efficacious and can also better evaluate the effect of known quantities of foods and nutrients on physiology. However, they come with additional methodological complexities. Feeding trials also call for a variety of unique methodological considerations, not least of which relate to the design and delivery of diets to participants. This review aims to provide a comprehensive summary of recommendations for design and conduct of feeding trials, encompassing domiciled and nondomiciled feeding trials. Several pertinent aspects of trial design and methodology are discussed, including defining the study population to maximize retention, safety, and generalizability of findings, recommendations for design of control interventions and optimizing blinding, and specific considerations for clinical populations. A detailed stepwise process for menu design, development, validation, and delivery are also presented. These recommendations aim to facilitate methodologic consistency and execution of high-quality feeding trials, ultimately facilitating improved understanding of the role of diet in treating disease and the underpinning mechanisms.

Aims: To evaluate relationships between diet quality and cardiovascular outcomes. Methods: Six databases were searched for studies published between January 2007 and October 2021. Eligible studies included cohort studies that assessed the relationship between a priori diet quality and cardiovascular disease mortality and morbidity in adults. The Academy of Nutrition and Dietetics Checklist was used to assess the risk of bias. Study characteristics and outcomes were extracted from eligible studies using standardised processes. Data were summarised using risk ratios for cardiovascular disease incidence and mortality with difference compared for highest versus lowest diet quality synthesised in meta-analyses using a random effects model. Results: Of the 4780 studies identified, 159 studies (n = 6 272 676 adults) were included. Meta-analyses identified a significantly lower cardiovascular disease incidence (n = 42 studies, relative risk 0.83, 95% CI 0.82¿0.84, p < 0.001) and mortality risk (n = 49 studies, relative risk 0.83, 95% CI 0.82¿0.84, p < 0.001) among those with highest versus lowest diet quality. In sensitivity analyses of a high number of pooled studies (=13 studies) the Mediterranean style diet patterns and adherence to the heart healthy diet guidelines were significantly associated with a risk reduction of 15% and 14% for cardiovascular disease incidence and 17% and 20% for cardiovascular disease mortality respectively (p < 0.05). Conclusions: Higher diet quality is associated with lower incidence and risk of mortality for cardiovascular disease however, significant study heterogeneity was identified for these relationships.

Vitamins play an intrinsic role in human health and are targets for clinical intervention through dietary or pharmacological approaches. Biomarkers of vitamin status are complex traits, measurable phenotypes that arise from an interplay between dietary and other environmental factors with a genetic component that is polygenic, meaning many genes are plausibly involved. Studying these genetic influences will improve our knowledge of fundamental vitamin biochemistry, refine estimates of the effects of vitamins on human health, and may in future prove clinically actionable. Here, we evaluate genetic studies of circulating and excreted biomarkers of vitamin status in the era of hypothesis-free genome-wide association studies (GWAS) that have provided unprecedented insights into the genetic architecture of these traits. We found that the most comprehensive and well-powered GWAS currently available were for circulating status biomarkers of vitamin A, C, D, and a subset of the B vitamins (B9 and B12). The biology implicated by GWAS of measured biomarkers of each vitamin is then discussed, both in terms of key genes and higher-order processes. Across all major vitamins, there were genetic signals revealed by GWAS that could be directly linked with known vitamin biochemistry. We also outline how genetic variants associated with vitamin status biomarkers have been already extensively used to estimate causal effects of vitamins on human health outcomes, which is particularly important given the large number of randomized control trials of vitamin related interventions with null findings. Finally, we discuss the current evidence for the clinical applicability of findings from vitamin GWAS, along with future directions for the field to maximize the utility of these data.

Diet quality is influenced by demographics and can change over time. This study aimed to (1) compare diet quality among adolescents/adults who completed the online Healthy Eating Quiz (HEQ) by demographic characteristics, and (2) to evaluate change in score over time for repeat completers. HEQ data collected between July 2016 and May 2022 were analysed, including demographics (age, gender, vegetarian status, socio-economic status, number of people main meals are shared with, country), and diet quality calculated using the Australian Recommended Food Score (ARFS) (range 0¿73) for respondents aged = 16 years. Differences in ARFS by demographic characteristics and change in score over time, adjusted for age, gender and vegetarian status, were tested by linear regression. The participants (n = 176,075) were predominantly female (70.4%), Australian (62.8%), and aged 18¿24 years (27.7%), with 4.0% (n = 7087) repeat completers. Mean ± SD ARFS was 33.9 ± 9.4/73. Results indicate that ARFS was significantly lower among males and significantly higher with increasing age group, higher socio-economic status, in vegetarians, those who shared main meals with others, and those living in Australia (p-values < 0.001). Mean change in ARFS over time (2.3 ± 6.9) was significantly higher for those with lower baseline scores (p < 0.001). Publicly available, brief dietary assessment tools have the potential to improve diet quality at the population level.

Objective: To investigate associations between eating behavior constructs (social eating, perceived competence, habit automaticity, self-determined motivation) and diet quality among young adults. Design: Cross-sectional analysis. Participants: Young adults (n = 1,005; mean age, 21.7 ± 2.0 years; 85% female) enrolled in the Advice, Ideas, and Motivation for My Eating (Aim4Me) study. Main outcome measures: Four eating behavior measures collected via online surveys: Social Eating Scale, Perceived Competence in Healthy Eating Scale, Self-Report Behavioral Automaticity Index, and Regulation of Eating Behaviors scales. Diet quality was assessed using the Australian Recommended Food Score (ARFS) and percentage energy from energy-dense, nutrient-poor (EDNP) foods. Analysis: Multivariate linear regression investigating associations between eating behavior measures (independent variables) and ARFS and EDNP foods (dependent variables), adjusting for sociodemographic and lifestyle confounders. Results: Greater perceived competence in healthy eating and behavioral automaticity for consuming healthy foods, limiting EDNP food intake, and higher intrinsic motivation, integrated regulation, and identified regulation of eating behaviors were associated with higher ARFS and lower percentage energy EDNP foods (P < 0.001). Greater self-reported social influence on eating behaviors was associated with higher ARFS (P = 0.01). Higher amotivation was associated with greater % energy from EDNP foods (P < 0.001). Conclusions and Implications: Perceived competence, habit automaticity, and self-determined motivation are determinants of diet quality in young adults. These findings support the development of interventions that promote healthy eating habits by focusing on eating behavior constructs and evaluating their use in improving diet quality.

Aim: To investigate associations between changes in vegetable and fruit (V&F) intakes and anthropometric indices (weight, BMI, % body fat, waist circumference), including differences by sex, during a dietary weight-loss intervention. Methods: Adults (18-45 years) with overweight/obesity (BMI 25-35 kg/m2) entered a 10-week pre-post study, receiving individualised consults with an Accredited Practising Dietitian targeting increased V&F intakes. Dietary intake was assessed using 24-hour recalls and food frequency questionnaires. Linear mixed models were used to examine how much of the changes in anthropometric indices were explained by changes in V&F intakes. Sex differences were assessed by Wilcoxon rank sum tests. Results: Of the 43 participants enrolled, 34 completed the study (53% female). Significant differences in energy intake and anthropometric indices were observed between males and females at baseline. After 10 weeks, females significantly reduced their weight (-2.9%, P <.01), BMI (-0.82 kg/m2, P <.01), waist circumference (-1.70 cm, P <.01), energy intake (-824 kJ/day, P =.01) and improved diet quality (-14.0% energy-dense, nutrient-poor foods, P <.01). Males significantly reduced weight (-2.5%, P =.04), BMI (-0.76 kg/m2, P =.03), waist circumference (-2.40 cm, P =.02), energy intake (-2875 kJ/day, P <.01), increased fruit intake (+0.89 serves/day, P =.02) and improved diet quality (-6% energy-dense, nutrient-poor foods, P <.01). Compared to the other sex, greater reductions were observed in energy intake in males and energy-dense, nutrient-poor foods in females. Linear mixed models identified that changes in V&F intakes did not explain the variation in anthropometric measures. Conclusion: Future interventions may benefit from trialling sex tailored messages to enhance effects on anthropometric changes.

Dietary intakes are commonly assessed by established methods including food frequency questionnaires, food records, or recalls. These self-report methods have limitations impacting validity and reliability. Dietary biomarkers provide objective verification of self-reported food intakes, and represent a rapidly evolving area. This review aims to summarize the urinary biomarkers of individual foods, food groups, dietary patterns, or nutritional supplements that have been evaluated to date. Six electronic databases were searched. Included studies involved healthy populations, were published from 2000, and compared measured dietary intake with urinary markers. The initial search identified 9985 studies; of these, 616 full texts were retrieved and 109 full texts were included. Of the included studies, 67 foods and food components were studied, and 347 unique urinary biomarkers were identified. The most reliable biomarkers identified were whole grains (alkylresorcinols), soy (isoflavones), and sugar (sucrose and fructose). While numerous novel urinary biomarkers have been identified, further validation studies are warranted to verify the accuracy of self-reported intakes and utility within practice.

Background: This systematic review aimed to evaluate the impact of nutrition interventions on participant reported pain severity and intensity in populations with chronic pain. Methods: Eight databases were systematically searched for studies that included adult populations with a chronic pain condition, a nutrition intervention and a measure of pain. Where possible, data were pooled using meta-analysis. Seventy-one studies were included, with 23 being eligible for meta-analysis. Results: Studies were categorised into four groups: (i) altered overall diet with 12 of 16 studies finding a significant reduction in participant reported pain; (ii) altered specific nutrients with two of five studies reporting a significant reduction in participant reported pain; (iii) supplement-based interventions with 11 of 46 studies showing a significant reduction in pain; and (iv) fasting therapy with one of four studies reporting a significant reduction in pain. The meta-analysis found that, overall, nutrition interventions had a significant effect on pain reduction with studies testing an altered overall diet or just one nutrient having the greatest effect. Conclusions: This review highlights the importance and effectiveness of nutrition interventions for people who experience chronic pain.