To examine the association between snack characteristics (snack frequency, snack energy density (ED) and snack nutritional quality) with diet quality and cardiometabolic risks among U.S. adolescents from the 2009-2016 National Health and Nutrition Examination Survey (NHANES). Cross-sectional dietary data collected using a 24-hour dietary recall from the 2011-2016 National Health and Nutrition Examination Survey (1,999 boys and 1,897 girls aged 12–19 years) were analysed. Associations between snack characteristics with diet quality, fasting blood glucose, triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein, blood pressure, waist circumference, metabolic syndrome risk score using multiple linear regression, were analysed stratified by sex. Higher snack nutritional quality (β [95% CI]: boys 0.31 [0.09, 0.52]; girls 0.44 [0.30, 0.57]) was linked to better overall diet quality, whereas snack ED excluding beverages (β [95% CI]: boys –1.82 [–2.52, –1.12]; girls –1.75 [–2.69, –0.82]) was linked to poorer overall diet quality. Among girls, higher snack frequency was associated with lower waist circumference and lower fasting blood glucose (-0.67 [-1.28, -0.05]). Additionally, higher snack ED and nutritional quality was associated with lower waist circumference and triglycerides, respectively. No associations between snack characteristics and cardiometabolic indicators or metabolic syndrome risk score were observed for boys. Findings suggest strategies to improve adolescent snack nutritional quality and ED may improve overall diet quality. However, limited associations were observed between snack characteristics and cardiometabolic risk indicators among girls only. Prospective studies are needed to further investigate the relationship between snack characteristics and adolescent health outcomes.

Children with Coeliac disease (CD) on a gluten-free diet (GFD) often have poor dietary quality (DQ). A Gluten-Free Food Guide (GFFG) was developed to address this. This pilot randomized controlled trial evaluated the impact of GFFG dietary counselling on DQ and ultra-processed food (UPF) intake in newly diagnosed CD children. Child-parent pairs were randomized to the standard of care only (CON: n = 20) or the intervention (INT: standard of care + GFFG; n = 20). Primary outcomes included DQ (Healthy Eating Index-Canadian) and UPF intake (NOVA classification), assessed at baseline (BL), 3 and 6 months. In INT, dietary variety scores, a subcomponent of DQ, increased between BL-3mo (BL: 6.7 [3.3-6.7] vs. 3mo: 10 [10-10]; p = 0.01), and in higher variety scores than CON at 3 months (p < 0.01). Total DQ and UPF intake remained unchanged. Increased dietary variety in INT was associated with increases in dairy (BL: 7.5 ± 3.6% vs. 3mo: 12.4 ± 6.7%; p = 0.01) and unsweetened milk (BL: 2.5 ± 2.2% vs. 3mo: 4.7 ± 3.0%; p = 0.01) servings, consumed as a percentage of the total food group servings. These improvements were not observed at 6 months. A greater number of INT children met the GFFG protein recommendation at 3 months (BL: 0/19 vs. 3 mo: 5/19; p = 0.01), with no change in CON. A single GFFG session improved short-term dietary variety and unsweetened milk intake. Ongoing work addressing the GF-food environment, dietitian access, and policies to improve DQ is needed.

Ultra-processed foods (UPFs) are often energy-dense and low in nutrients. High consumption of UPFs has been associated with non-communicable diseases, premature mortality and environmental impacts. The objective of this study was to assess UPF consumption in relation to diet quality and associated greenhouse gas (GHG) emissions, previously not examined in Iceland. Data from the Icelandic National Dietary Survey (2019-2021, N=822) were utilized. The NOVA classification system was used classifying all food and drinks reported. Dietary GHG emissions were quantified using an open-source LCA database. On average, 45%±15 of the total calories consumed daily were derived from UPFs, ranging from 24% in the lowest quartile (UPFQ1) to 64% in the highest quartile (UPFQ4). The energy contribution of UPFs considered to fall within the Icelandic dietary guidelines was 4%±4. UPFQ4 had significantly lower consumption of e.g. red meat, fruits, vegetables and whole grains, and higher consumption of e.g. refined grains, sweets, and soft drinks, compared to UPFQ1. UPFQ4 had a significantly higher energy intake, added sugar intake, and lower intake of e.g. proteins and iodine. The median [IQR] share of dietary GHG emissions was 21% [IQR:11,34] of total kg CO2-eq/day, while significantly lower in UPFQ4 compared to UPFQ1.

Almost half of the daily energy intake of Icelandic diets was derived from UPFs, reflecting relatively poor diet quality. However, dietary GHG emissions were relatively low in high consumers of UPF, reflecting higher meat consumption in low consumers of UPF. Findings underline the urgency of policy implementation, aligning food consumption with dietary guidelines.

This cross-sectional study examined the association between diet price and diet quality in a national sample of Australian adults (n 1956). Diet recall data from the 2020 International Food Policy Study were linked to a national food and beverage price dataset. Daily diet price was calculated by summing the median non-promotional prices of all foods and beverages recorded in diet recall data, priced per gram (or millilitre) and adjusted for edible portions. Diet quality was determined using the Australian Dietary Guideline Index 2013 (scored out of 115). Linear regression models tested the association between the diet price (per dollar and per ten-dollar increments) and diet quality, adjusted for education, age and sex. A positive association was observed, where diet quality increased by 0·09 units (95 % CI 0·05, 0·14) for every $AU 1 increase in diet price. Daily diet price explained approximately 8 % of the variation in diet quality across the sample (R2 = 0·08). When categorised in ten-dollar increments, participants with diet prices < $AU 10/d had a lower mean diet quality score (51·96) compared with all other diet price categories, 5–6 points lower than those whose diet was > $30/d. Diet price appeared to be a modest yet significant determinant of diet quality for Australian adults in 2020. Additional analyses are needed to investigate these associations during recent food inflation. As diet quality appears to be lowest for people who spend the least on food, government action to increase priority communities’ food budgets may help improve the nutritional quality of population diets.

Previous studies demonstrated that ultra-processed foods (UPF) affect overall diet quality. However, none have yet examined this relation across different age groups in Brazil. This study assessed the relationship between diet quality and the consumption of UPF in a Brazilian population according to age groups. This was a cross-sectional study that analysed food consumption data from 46 164 Brazilians aged ≥10 years who participated in the 2017–2018 National Dietary Survey. Food and beverages consumed were recorded by two 24-h recalls. All food items were classified as UPF or non-UPF according to the Nova system. Diet quality was evaluated using nutritional density and the prevalence of inadequate nutrient consumption, according to the quintiles of energy contribution of UPF. The association between diet quality and UPF consumption was evaluated by linear and Poisson regressions, with adjustment for sociodemographic variables, stratified by age groups (adolescents, adults and older adults). The consumption of UPF increased the densities of carbohydrates, free sugar, saturated fat and Na and decreased the densities of proteins, fibres and potassium in three age groups. Higher prevalence ratios (PR) of inadequate consumption of free sugar and fibre among the lower and higher quintiles of energy contribution of UPF among adolescents (PR = 2·02, 95 % CI = 1·82, 2·25; PR = 1·88, 95 % CI = 1·68, 2·10), adults (PR = 1·86, 95 % CI = 1·75, 1·98; PR = 1·70, 95 % CI = 1·60, 1·80) and older adults (PR = 1·48, 95 % CI = 1·30, 1·69; PR = 1·24, 95 % CI = 1·09, 1·40). UPF consumption was negatively associated with diet quality across different age groups. Thus, interventions targeting UPF consumption should be implemented across life stages to improve overall diet quality.

There has been substantial research undertaken on the role of a health-promoting diet in depression. Yet, the evidence of the relationship between the Nordic diet and the risk of depression is scarce. This cross-sectional study aimed to assess whether a healthy Nordic diet is associated with depressive symptoms. In total, 2603 men aged 42–60 years from the Kuopio Ischaemic Heart Disease Risk Factor Study were included. Diet quality was evaluated with a healthy Nordic diet score derived from the 4-day food diaries and depressive symptoms with the self-reported Human Population Laboratory (HPL) depression scale. Quade ANCOVA was used to examine the mean values of HPL scores in quartiles of a healthy Nordic diet score. Participants’ mean age was 53 years and BMI 26·8 kg/m2; 31·7 % were current smokers, and 86·9 % were married or living as a couple. The mean healthy Nordic diet score was 12·8 (sd 4·0, range 2–25), and the mean HPL depression score was 1·9 (sd 2·1, range 0–13). The findings suggested that lower adherence to a healthy Nordic diet was associated with higher HPL depression scores after adjusting for age, examination year, daily energy intake, leisure-time physical activity, adulthood socio-economic status, smoking and marital status (extreme quartile difference: 0·33 points, 95 % CI 0·10, 0·56, P for trend across the quartiles = 0·003). The results support the hypothesis that a lower-quality diet increases the odds of having depressive symptoms. However, prospective studies are needed to confirm the association.

The RDA for dietary protein is likely insufficient for individuals with cystic fibrosis (CF). This study sought to characterise protein intake and diet quality in adults with cystic fibrosis (awCF), before and after elexacaftor/tezacaftor/ivacaftor (ETI) therapy, compared with healthy controls. Dietary intake was assessed by diet diary in awCF at baseline (BL, n 40) and at follow-up > 3 months post ETI therapy (follow-up (FUP), n 40) and in age-matched healthy controls (CON, n 80) free from known disease at a single time point. Protein intake dose and daily distribution, protein quality, protein source and overall diet quality were calculated for each participant. Both CON (1·39 (sd 0·47) g·kg–1·day–1) and CF (BL: 1·44 (sd 0·52) g·kg–1·day–1, FUP: 1·12 (sd 0·32) g·kg–1·day–1) had a higher mean daily protein intake than the protein RDA of 0·75g·kg–1·day–1. There was a significant reduction in daily protein intake in the CF group at FUP (P = 0·0003, d = 0·73), with levels below the alternative suggested dietary intake of ≥ 1·2 g·kg–1·day–1. There were no sex differences or noticeable effects on protein quality or source following the commencement of ETI therapy when compared with CON (all P > 0·05), although overall diet quality decreased between time points (P = 0·027, d = 0·57). The observed reduction in daily protein intake in the present cohort emphasises the importance of ensuring appropriate dietary protein intake to promote healthy ageing in adults with CF. More research is needed to evidence base dietary protein requirements in this at-risk population.

Diet quality has been linked to socio-economic status. However, evidence within rural and regional populations is lacking. This cross-sectional study examined the relationship between diet quality and socio-economic position in adults living in rural and regional areas of Australia. The Australian Recommended Food Score (ARFS; range 0–73) measured diet quality (total and subscale scores). Area-level socio-economic position was determined by postcode-linked socio-economic index for areas (SEIFA), Index of Relative Social Advantage and Disadvantage scores, stratified into quintiles. The mean total ARFS (34·7; sd = 9·1; n 836) was classified as ‘getting there’. Findings showed significantly lower mean total ARFS between SEIFA quintile 1 (1 = lowest; mean total ARFS = 30·4; sd = 10·2; categorised as ‘needs work’) compared with all other SEIFA quintiles (F (44 831) = 8·44, P ≤ 0·001). Linear regression, adjusting for age, sex, income, education, employment status and household composition demonstrated significantly lower overall diet quality for SEIFA quintile 1 compared with SEIFA quintile 3 (B = –3·9; 95 % CI (–6·2, −1·5); P < 0·001) and lower subscale scores for vegetables (B = –1·6; 95 % CI (–2·7, −0·6); P = 0·003), fruit (B = –0·9; 95 % CI (–1·6, −0·1); P = 0·018) and grains (B = –0·6; 95 % CI (–1·3, −0·0); P = 0·050). After adjusting for individual confounders of diet quality, results indicate that lower area-level socio-economic position remained associated with poorer diet quality in this sample of rural and regional Australian adults. This suggests that broader social and environmental factors unique to these areas may impact diet quality and amplify individual barriers to achieving a healthy diet.

Food insecurity (FIS) is a critical public health issue, particularly among older adults. This study investigates the association between FIS with diet quality and anthropometric indices in the US older adults. A cross-sectional analysis was conducted using NHANES data from 2017 to 2020, involving 2592 participants aged ≥ 60 years. FIS was assessed using the USDA Household Food Security Survey Module. Diet quality was assessed using the Healthy Eating Index (HEI)-2020 and adherence to Mediterranean diet (MedDiet) score. Anthropometric measures were calculated following standardised protocols. Multivariable logistic regression models, adjusted for demographic, socio-economic and behavioural factors examined the association between FIS and the higher quartile and tertile of anthropometric and diet quality indices, respectively. Of the participants, 27·4 % experienced FIS. FIS participants were younger and had lower education and income levels compared with FS individuals (P < 0·05). In the adjusted model, FIS was associated with lower adherence to both the Mediterranean Diet (OR: 0·48, 95 % CI: 0·31, 0·67) and HEI-2020 (OR: 0·61, 95 % CI: 0·37, 0·84), indicating poorer diet quality in older adults. In adjusted analyses, FIS was significantly associated with higher A Body Shape Index quartiles (Q3: OR: 1·44, 95 % CI: 1·06, 1·95; Q4: OR: 1·46, 95 % CI: 1·07, 2·01), the waist-to-hip ratio (Q4: OR: 1·44, 95 % CI: 1·01, 2·06) and the Conicity index (Q4: OR: 1·36, 95 % CI: 1·02, 1·81). FIS in older adults is associated with unfavourable diet quality and body composition patterns, particularly central obesity measures. Addressing FIS may mitigate health risks related to obesity and its complications.

The purpose of this study was to measure meal quality in representative samples of schoolchildren in three cities located in different Brazilian regions using the Meal and Snack Assessment Quality (MESA) scale and examine association with weight status, socio-demographic characteristics and behavioural variables. This cross-sectional study analysed data on 5612 schoolchildren aged 7–12 years who resided in cities in Southern, Southeastern and Northeastern Brazil. Dietary intake was evaluated using the WebCAAFE questionnaire. Body weight and height were measured to calculate the BMI. Weight status was classified based on age- and sex-specific Z-scores. Meal quality was measured using the MESA scale. Associations of meal quality with weight status and socio-demographic and behavioural variables were investigated using multinomial regression analysis. Schoolchildren in Feira de Santana, São Paulo and Florianópolis had a predominance of healthy (41·8 %), mixed (44·4 %) and unhealthy (42·7 %) meal quality, respectively. There was no association with weight status. Schoolchildren living in Feira de Santana, those who reported weekday dietary intakes, and those with lower physical activity and screen activity scores showed higher meal quality. Schoolchildren aged 10–12 years, those who reported dietary intakes relative to weekend days, and those with higher screen activity scores exhibited lower meal quality.

Assessing children’s diets is currently challenging and burdensome. Abbreviated FFQ have the potential to assess dietary patterns in a rapid and standardised manner. Using nationally representative UK dietary intake and biomarker data, we developed an abbreviated FFQ to calculate dietary quality scores for pre-school and primary school-aged children. UK National Diet and Nutrition Survey (2008–2016) weekly consumption frequencies of 129 food groups from 4-d diaries were cross-sectionally analysed using principal component analysis. A 129-item score was derived, alongside a 12-item score based on foods with the six highest and six lowest coefficients. Participants included 1069 pre-schoolers and 2565 primary schoolchildren. The first principal component explained 3·4 and 3·0 % of the variation in the original diet variables for pre-school and primary school groups, respectively, and described a prudent diet pattern. Prudent diet scores were characterised by greater consumption of fruit, vegetables and tap water and lower consumption of crisps, manufactured coated chicken/turkey products, purchased chips and soft drinks for both age groups. Correlations between the 129-item and 12-item scores were 0·86 and 0·84 for pre-school and primary school-aged children, respectively. Bland–Altman mean differences between the scores were 0·00 sd; 95 % limits of agreement were −1·05 to 1·05 and −1·10 to 1·10 sd for pre-school and primary school-aged children, respectively. Correlations between dietary scores and nutritional biomarkers showed only minor attenuation for the 12-item compared with the 129-item scores, illustrating acceptable congruence between prudent diet scores. The two 12-item FFQ offer user-friendly tools to measure dietary quality among UK children.

Dietary guidelines often combine plant and animal protein intake recommendations, yet evidence suggests they may have distinct associations with health. This study aimed to examine relationships between animal and plant protein intake, using different classification approaches, and diet quality and obesity. Plant and animal protein contents of foods reported by 7637 participants (≥ 19 years) during the 2011–2012 National Nutrition and Physical Activity Survey were estimated using Australian food composition databases. Usual animal, plant and total protein intakes were estimated using Multiple Source Methods. Diet quality was assessed using the 2013-Dietary Guidelines Index (DGI), and obesity measures included BMI and waist circumference (WC). Multiple linear and logistic regressions were performed and adjusted for potential confounders. Plant and animal protein intakes were positively associated with DGI scores (plant protein: men, β = 0·74 (95 % CI: 0·64, 0·85); women, β = 0·78 (0·67, 0·89); animal protein: men, β = 0·15 (0·12, 0·18); women, β = 0·26 (0·22, 0·29)). These associations were consistent when examining high-quality plant protein (high-protein-containing plant-based foods with comparable nutritional values to animal proteins) and non-dairy animal protein intakes. Plant protein intake was inversely associated with BMI and WC in men but not women. Animal protein intake was positively associated with BMI in both sexes and WC in men only. Men’s plant protein intake was inversely associated with obesity (OR = 0·97 (0·96, 0·99)) and central obesity (OR = 0·97 (0·95, 0·98)). Further studies are needed to examine the influence of different animal protein sources by accounting for energy intake and sex-specific associations.

Studies on longitudinal associations between diet quality and lipid and amino acid metabolism in children and adolescents are limited. We studied associations between diet quality and serum markers of lipid and amino acid metabolism in the Physical Activity and Nutrition in Children (PANIC) study. These analyses included 403 children aged 6–9 years at baseline, 360 re-examined 2 years later at age 9–11 years and 219 eight years later at age 15–17 years. Food intake was recorded over 4 days, and diet quality was assessed using the Finnish Children Healthy Eating Index (FCHEI). Fasting serum fatty acids, amino acids, apolipoproteins and lipoprotein particle sizes were analysed via NMR spectroscopy. Linear mixed-effects models, adjusted for sex, age, body fat percentage, pubertal stage and physical activity were used to analyse the associations. Better diet quality was linked to increased serum PUFA and reduced saturated and MUFA, alanine and VLDL particle size. Consuming more vegetables, fruits, berries, vegetable oils and margarine with at least 60 % fat, fish and whole grains is associated with higher serum PUFA, lower SFA and smaller VLDL particles. Conversely, consuming higher-fat dairy products and sugary products is associated with higher saturated and MUFA, branched-chain and aromatic amino acids and larger VLDL particles. A diet rich in fruits, vegetables, unsaturated fats and fibre, with reduced sugar consumption, promotes favourable metabolic changes relevant to cardiometabolic health.

There is a growing focus on understanding the complexity of dietary patterns and how they relate to health and other factors. Approaches that have not traditionally been applied to characterise dietary patterns, such as latent class analysis and machine learning algorithms, may offer opportunities to characterise dietary patterns in greater depth than previously considered. However, there has not been a formal examination of how this wide range of approaches has been applied to characterise dietary patterns. This scoping review synthesised literature from 2005 to 2022 applying methods not traditionally used to characterise dietary patterns, referred to as novel methods. MEDLINE, CINAHL and Scopus were searched using keywords including latent class analysis, machine learning and least absolute shrinkage and selection operator. Of 5274 records identified, 24 met the inclusion criteria. Twelve of twenty-four articles were published since 2020. Studies were conducted across seventeen countries. Nine studies used approaches with applications in machine learning, such as classification models, neural networks and probabilistic graphical models, to identify dietary patterns. The remaining studies applied methods such as latent class analysis, mutual information and treelet transform. Fourteen studies assessed associations between dietary patterns characterised using novel methods and health outcomes, including cancer, cardiovascular disease and asthma. There was wide variation in the methods applied to characterise dietary patterns and in how these methods were described. The extension of reporting guidelines and quality appraisal tools relevant to nutrition research to consider specific features of novel methods may facilitate consistent reporting and enable synthesis to inform policies and programs.

Postpartum maternal diet quality has been linked with optimal infant feeding practices. However, whether maternal diet quality during pregnancy influences infant feeding practices remains unclear. The present study explored the relationship between maternal diet quality in pregnancy and infant feeding practices in Australian women. A brief 15-item FFQ was used to collect maternal dietary data (n 469). Diet quality was calculated using a modified 2013 Dietary Guideline Index (DGI). Multivariable linear and logistic regressions with adjustment for covariates were used to examine associations between maternal diet quality in pregnancy and infant feeding practices: infant feeding mode, breast-feeding duration and timing of solids introduction. Higher DGI score during pregnancy was associated with higher odds of breast-feeding than formula/mixed feeding (adjusted OR (AOR) 1·03, 95 % CI 1·00, 1·07), longer breast-feeding duration (adjusted β 0·09, 95 % CI 0·03, 0·15) and higher odds of breast-feeding for ≥ 6 months (AOR 1·04, 95 % CI 1·02, 1·07) than for < 6 months. Associations between maternal DGI score and breast-feeding variables were moderated by maternal country of birth, with significant associations observed in Australian-born mothers only. No association was found between maternal DGI score and timing of solids introduction. Higher maternal diet quality was associated with better infant feeding practices, and the association was moderated by country of birth. Our findings provide evidence to support the initiation of dietary interventions to promote diet quality during pregnancy, particularly among Australian-born women. Further research could explore underlying mechanisms linking maternal diet quality and infant feeding practices.

The aim of this study was to examine the relationship between nutrition knowledge and nutritional adequacy among Japanese university students. This cross-sectional study was conducted in 2018 at a university located in Hyogo Prefecture, Kobe, Japan, and 801 students from various academic disciplines were enrolled. Eligible participants were students aged more than 18 years, encompassing all years of study. Nutrition knowledge data were obtained using a nutrition knowledge questionnaire (NKQ) for Japanese adults. Participants were classified into three nutrition knowledge groups according to their total NKQ scores [mean ± standard deviation; all (64.7 ± 15.4%), low (48.1 ± 13.8%), medium (68.3 ± 2.8%), and high (78.5 ± 4.2%)]. Participants reported their dietary habits in the preceding month using a brief self-administered diet history questionnaire. Differences in nutritional adequacy among groups were determined using logistic regression and covariance analyses, adjusted for potential confounding factors. The adequacy of each nutrient was quantified as the proportion of participants with nutrient intake that fell outside the reference range. Although the intakes of only a few nutrients and foods were associated with nutrition knowledge, the total number of nutrients below the estimated average requirement was lower in the high nutrition knowledge group (3.1 ± 2.7) than in the low nutrition knowledge group (3.6 ± 2.9) (P = 0.046). In conclusion, the nutrition knowledge level of Japanese university students is associated with nutritional adequacy but may partially affect eating habits. Future longitudinal studies must clarify the causal and dose-response relationships between nutrition knowledge and dietary habits.

Lifestyle has been associated with in vitro fertilisation (IVF) success rates, but studies on diet and IVF outcomes are inconclusive. We studied associations between adherence to the Dutch guidelines for a Healthy diet 2015 and pregnancy chances among women receiving modified natural cycle in vitro fertilisation (MNC-IVF). This prospective cohort study utilised data from 109 women undergoing MNC-IVF between 2014 and 2018 at University Medical Centre Groningen enrolled in a study examining associations between metabolic profile of follicular fluid and oocyte quality. Adherence to dietary guidelines was assessed by daily food records quantified based on the Dutch Healthy Diet (DHD) 2015 Index. IVF outcomes (i.e. positive pregnancy test, ongoing pregnancy, and live birth) were obtained from patient records. Statistical analyses involved Cox proportional hazard regression analyses while adjusting for maternal covariates age, smoking, and Body Mass Index (BMI), and stratified for treatment, age, BMI, and energy intake. Women were 31.5 ± 3.3 years old, and had a BMI of 23.5 ± 3.5 kg/m2. Higher DHD2015 adherence was linked to a reduced probability of achieving an ongoing pregnancy (HR = 0.77, 95%CI: 0.62–0.96), live birth (HR = 0.78, 95%CI: 0.62–0.98), and showed a non-significant trend towards a lower probability of a positive pregnancy test (HR = 0.85, 95%CI: 0.71–1.01). Associations were particularly present among women undergoing MNC-ICSI (n = 87, p-for-interaction = 0.06), with shorter duration of infertility (n = 44, p-for-interaction=0.06), being overweight (n = 31, p-for interaction = 0.11), and having higher energy intakes (n = 55, p-for-interaction = 0.14). This explorative study suggests inverse trends between DHD2015 adherence and MNC-IVF outcomes, encouraging well-powered stratified analyses in larger studies to further explore these unexpected findings.